A Review of Indocyanine Green Fluorescent Imaging in Surgery
---
paper_title: Microscope Image Processing

paper_content:

Digital image processing, an integral part of microscopy, is increasingly important to the fields of medicine and scientific research. This book provides a unique one-stop reference on the theory, technique, and applications of this technology.Written by leading experts in the field, this book presents a unique practical perspective of state-of-the-art microscope image processing and the development of specialized algorithms. It contains in-depth analysis of methods coupled with the results of specific real-world experiments. Microscope Image Processing covers image digitization and display, object measurement and classification, autofocusing, and structured illumination.Key Features:. Detailed descriptions of many leading-edge methods and algorithms. In-depth analysis of the method and experimental results, taken from real-life examples. Emphasis on computational and algorithmic aspects of microscope image processing.Advanced material on geometric, morphological, and wavelet image processing, fluorescence, three-dimensional and time-lapse microscopy, microscope image enhancement, MultiSpectral imaging, and image data managementThis book is of interest to all scientists, engineers, clinicians, post-graduate fellows, and graduate students working in the fields of biology, medicine, chemistry, pharmacology, and other related fields. Anyone who uses microscopes in their work and needs to understand the methodologies and capabilities of the latest digital image processing techniques will find this book invaluable. * Presents a unique practical perspective of state-of-the-art microcope image processing and the development of specialized algorithms.* Each chapter includes in-depth analysis of methods coupled with the results of specific real-world experiments.* Co-edited by Kenneth R. Castleman, world-renowned pioneer in digital image processing and author of two seminal textbooks on the subject.
---
paper_title: Fluorescence-enhanced, near infrared diagnostic imaging with contrast agents.

paper_content:

The deep tissue propagation of near-infrared (NIR) light between 700-900 nm offers new opportunities for diagnostic imaging when employing sensitive detection techniques and NIR excitable fluorescent agents that target and report disease and metabolism. Herein, we highlight approaches for illuminating tissues and monitoring the re-emitted fluorescence for tomographic reconstruction, strategies for developing fluorescent dye constructs, and clinical opportunities for fluorescence-enhanced NIR optical imaging.
---
paper_title: Dynamic fluorescence imaging for multiparametric measurement of tumor vasculature

paper_content:

Angiogenesis is essential for tumor growth and a promising target for cancer therapy. Blood vessel monitoring is an indispensable tool for evaluation and development of anti-angiogenic drugs. Here, we report a new noninvasive in vivo imaging tool, named dynamic fluorescence imaging (DyFI), for the simultaneous measurement of multiple vascular parameters including vascular density, perfusion rate, and permeability using spatiotemporal profiles of indocyanine green. Using DyFI in a tumor xenograft model, we quantitatively measured multiple vascular parameters in tumors and normal tissues with high spatial resolution. The multimodality of this method allowed us to find negative spatial correlations between perfusion and permeability. Moreover, DyFI was effective for revealing the early effects of an anti-angiogenic drug. We suggest that DyFI could be a useful tool for the preclinical development of anti-angiogenic drugs.
---
paper_title: Hands-free, wireless goggles for near-infrared fluorescence and real-time image-guided surgery.

paper_content:

BACKGROUND ::: Current cancer management faces several challenges, including the occurrence of a residual tumor after resection, the use of radioactive materials or high concentrations of blue dyes for sentinel lymph node biopsy, and the use of bulky systems in surgical suites for image guidance. To overcome these limitations, we developed a real-time, intraoperative imaging device that, when combined with near infrared fluorescent molecular probes, can aid in the identification of tumor margins, guide surgical resections, map sentinel lymph nodes, and transfer acquired data wirelessly for remote analysis. ::: ::: ::: METHODS ::: We developed a new compact, wireless, wearable, and battery-operated device that allows for hands-free operation by surgeons. A charge-coupled device-based, consumer-grade night vision viewer was used to develop the detector portion of the device, and the light source portion was developed from a compact headlamp. This piece was retrofitted to provide both near infrared excitation and white light illumination simultaneously. Wireless communication was enabled by integrating a battery-operated, miniature, radio-frequency video transmitter into the system. We applied the device in several types of oncologic surgical procedures in murine models, including sentinel lymph node mapping, fluorescence-guided tumor resection, and surgery under remote expert guidance. ::: ::: ::: RESULTS ::: Unlike conventional imaging instruments, the device displays fluorescence information directly on its eyepiece. When employed in sentinel lymph node mapping, the locations of sentinel lymph nodes were visualized clearly, even with tracer level dosing of a near infrared fluorescent dye (indocyanine green). When used in tumor resection, tumor margins and small nodules invisible to the naked eye were visualized readily. In a simulated, point-of-care setting, tumors were located successfully and removed under remote guidance using the wireless feature of the device. Importantly, the total cost of this prototype system ($1200) is substantially less than existing imaging instruments. ::: ::: ::: CONCLUSION ::: Our results demonstrate the feasibility of using the new device to aid surgical resection of tumors, map sentinel lymph nodes, and facilitate telemedicine.
---
paper_title: Light-induced decomposition of indocyanine green.

paper_content:

PURPOSE ::: To investigate the light-induced decomposition of indocyanine green (ICG) and to test the cytotoxicity of light-induced ICG decomposition products. ::: ::: ::: METHODS ::: ICG in solution was irradiated with laser light, solar light, or surgical endolight. The light-induced decomposition of ICG was analyzed by high-performance liquid chromatography (HPLC) and mass spectrometry. Porcine retinal pigment epithelial (RPE) cells were incubated with the light-induced decomposition products of ICG, and cell viability was measured by trypan blue exclusion assay. ::: ::: ::: RESULTS ::: Independent of the light source used, singlet oxygen (photodynamic type 2 reaction) is generated by ICG leading to dioxetanes by [2+2]-cycloaddition of singlet oxygen. These dioxetanes thermally decompose into several carbonyl compounds. The decomposition products were identified by mass spectrometry. The decomposition of ICG was inhibited by adding sodium azide, a quencher of singlet oxygen. Incubation with ICG decomposition products significantly reduced the viability of RPE cells in contrast to control cells. ::: ::: ::: CONCLUSIONS ::: ICG is decomposed by light within a self-sensitized photo oxidation. The decomposition products reduce the viability of RPE cells in vitro. The toxic effects of decomposed ICG should be further investigated under in vivo conditions.
---
paper_title: Physicochemical studies of indocyanine green (ICG): absorbance/concentration relationship, pH tolerance and assay precision in various solvents

paper_content:

Indocyanine green (ICG) obeyed the Beer-Lambert law within the concentration range 1.25 micrograms/ml-10.0 micrograms/ml in distilled water, methanol, dimethylformamide (DMF), 1.2-propanediol and aqueous buffers (pH 9.0), but only up to 7.5 micrograms/ml in human bile and 0.5% human albumin, and only to 5.0 micrograms/ml in human duodenal fluid. ICG was rapidly (less than 1 h) decomposed to a colorless derivative at pH less than 5 and greater than 11, but remained relatively stable for 48 h at pH 8-10. ICG is an indicator and a weak acid with a pKa of 3.27. In bile stabilized with 25% methanol, the precision of the method (CV) is 5% and the accuracy is 106-127%.
---
paper_title: Vital staining with indocyanine green: a review of the clinical and experimental studies relating to safety

paper_content:

Indocyanine green (ICG) is extremely effective when used as a vital stain during macular hole surgery. By staining the internal limiting membrane, ICG facilitates removal of this delicate and sometimes hard to visualize structure. There is, however, considerable debate regarding its safety. This review considers the clinical and experimental studies of ICG and a related agent, infracyanine green. Some clinical papers show visual field defects, reduced visual acuity, and persistence of ICG at the macula and optic nerve. Other clinical studies fail to demonstrate toxicity. The experimental studies are also conflicting, but there are emerging trends. These suggest that surgeons who continue to use ICG should use concentrations not greater than 0.05 mg/ml, in fluid-filled eyes, with short exposure times, iso-osmolar solutions, and avoid proximal or prolonged endoillumination of stained tissue. A smaller number of studies suggest that infracyanine green produces similar staining to ICG, and may possibly be safer, but there are too few well-designed studies to reach a conclusion. Although the use of ICG continues, on the balance of evidence, this review suggests that it is has the potential to produce subtle visual damage.
---
paper_title: A review of NIR dyes in cancer targeting and imaging.

paper_content:

Abstract The development of multifunctional agents for simultaneous tumor targeting and near infrared (NIR) fluorescence imaging is expected to have significant impact on future personalized oncology owing to the very low tissue autofluorescence and high tissue penetration depth in the NIR spectrum window. Cancer NIR molecular imaging relies greatly on the development of stable, highly specific and sensitive molecular probes. Organic dyes have shown promising clinical implications as non-targeting agents for optical imaging in which indocyanine green has long been implemented in clinical use. Recently, significant progress has been made on the development of unique NIR dyes with tumor targeting properties. Current ongoing design strategies have overcome some of the limitations of conventional NIR organic dyes, such as poor hydrophilicity and photostability, low quantum yield, insufficient stability in biological system, low detection sensitivity, etc. This potential is further realized with the use of these NIR dyes or NIR dye-encapsulated nanoparticles by conjugation with tumor specific ligands (such as small molecules, peptides, proteins and antibodies) for tumor targeted imaging. Very recently, natively multifunctional NIR dyes that can preferentially accumulate in tumor cells without the need of chemical conjugation to tumor targeting ligands have been developed and these dyes have shown unique optical and pharmaceutical properties for biomedical imaging with superior signal-to-background contrast index. The main focus of this article is to provide a concise overview of newly developed NIR dyes and their potential applications in cancer targeting and imaging. The development of future multifunctional agents by combining targeting, imaging and even therapeutic routes will also be discussed. We believe these newly developed multifunctional NIR dyes will broaden current concept of tumor targeted imaging and hold promise to make an important contribution to the diagnosis and therapeutics for the treatment of cancer.
---
paper_title: Historical considerations in applying vital dyes in vitreoretinal surgery: from early experiments to advanced chromovitrectomy

paper_content:

This review describes the chronological development of different approaches to applying vital dyes in vitreoretinal surgery and the clinical implications of these developments. Previous experimental studies explored the intravenous, subretinal and intravitreal application of vital dyes. Since the year 2000, numerous dyes have been introduced for the recognition of thin semitransparent preretinal tissues during vitrectomy, a procedure known as chromovitrectomy. Recently, a novel instrument in a painting brush style, the Vitreoretinal INternal limiting membrane Colour Enhancer (VINCE), has become available for chromovitrectomy. Currently, there are six vital stains under evaluation for application during chromovitrectomy. Much of the animal research available, particularly on indocyanine green, indicates dose-dependent damage on the retinal tissue. Based on such observations, surgeons should use minimal concentrations and volume of intravitreous stains and the current trend is towards painting the retina ra...
---
paper_title: Current trends and emerging future of indocyanine green usage in surgery and oncology: a literature review.

paper_content:

Ever since Kitai first performed fluorescent navigation of sentinel lymph nodes (SLNs) using indocyanine green (ICG) dye with a charge-couple device and light emitting diodes, the intraoperative use of near infrared fluorescence has served a critical role in increasing our understanding in various fields of surgical oncology. Here the authors review the emerging role of the ICG fluorophore in the development of our comprehension of the lymphatic system and its use in SLN mapping and biopsy in various cancers. In addition, they introduce the novel role of ICG-guided video angiography as a new intraoperative method of assessing microvascular circulation. The authors attempt to discuss the promising potential in addition to assessing several challenges and limitations in the context of specific surgical procedures and ICG as a whole. PubMed and Medline literature databases were searched for ICG use in clinical surgical settings. Despite ICG's significant impact in various fields of surgical oncology, ICG is still in its nascent stages, and more in-depth studies need to be carried out to fully evaluate its potential and limitations.
---
paper_title: How to assess liver function?

paper_content:

PURPOSE OF REVIEW ::: The liver comprises a multitude of parenchymal and nonparenchymal cells with diverse metabolic, hemodynamic and immune functions. Available monitoring options consist of 'static' laboratory parameters, quantitative tests of liver function based on clearance, elimination or metabolite formation and scores, most notably the 'model for end-stage liver disease'. This review aims at balancing conventional markers against 'dynamic' tests in the critically ill. ::: ::: ::: RECENT FINDINGS ::: There is emerging evidence that conventional laboratory markers, most notably bilirubin, and the composite model for end-stage liver disease are superior to assess cirrhosis and their acute decompensation, while dynamic tests provide information in the absence of preexisting liver disease. Bilirubin and plasma disappearance rate of indocyanine green reflecting static and dynamic indicators of excretory dysfunction prognosticate unfavorable outcome, both, in the absence and presence of chronic liver disease better than other functions or indicators of injury. Although dye excretion is superior to conventional static parameters in the critically ill, it still underestimates impaired canalicular transport, an increasingly recognized facet of excretory dysfunction. ::: ::: ::: SUMMARY ::: Progress has been made in the last year to weigh static and dynamic tests to monitor parenchymal liver functions, whereas biomarkers to assess nonparenchymal functions remain largely obscure.
---
paper_title: Toxicity of Organic Fluorophores Used in Molecular Imaging: Literature Review

paper_content:

Fluorophores are potentially useful for in vivo cancer diagnosis. Using relatively inexpensive and portable equipment, optical imaging with fluorophores permits real-time detection of cancer. However, fluorophores can be toxic and must be investigated before they can be administered safely to patients. A review of published literature on the toxicity of 19 widely used fluorophores was conducted by searching 26 comprehensive biomedical and chemical literature databases and analyzing the retrieved material. These fluorophores included Alexa Fluor 488 and 514, BODIPY FL, BODIPY R6G, Cy 5.5, Cy 7, cypate, fluorescein, indocyanine green, Oregon green, 8-phenyl BODIPY, rhodamine 110, rhodamine 6G, rhodamine X, rhodol, TAMRA, Texas red, and Tokyo green. Information regarding cytotoxicity, tissue toxicity, in vivo toxicity, and mutagenicity was included. Considerable toxicity-related information was available for the Food and Drug Administration (FDA)-approved compounds indocyanine green and fluorescein, but published information on many of the non-FDA-approved fluorophores was limited. The information located was encouraging because the amounts of fluorophore used in molecular imaging probes are typically much lower than the toxic doses described in the literature. Ultimately, the most effective and appropriate probes for use in patients will be determined by their fluorescent characteristics and the safety of the conjugates.
---
paper_title: In Vivo Near-Infrared Fluorescence Imaging

paper_content:

In vivo near-infrared (NIR) fluorescence imaging used for clinical diagnostics and treatment monitoring provides a noninvasive approach for visualizing and peering deeply morphological details of tissues or living subjects with subcellular resolution. In this chapter, we describe the applications of organic dyes, metal complexes, fluorescent biomacromolecules, and nanoparticles (such as polymers, quantum dots (QDs), carbon-based nanomaterials, upconversion nanoparticles (UCNPs), noble metal clusters, and Si-based hybrid nanoparticles) for NIR fluorescence imaging of living subjects.
---
paper_title: Noninvasive assessment of burn wound severity using optical technology: A review of current and future modalities

paper_content:

Clinical examination alone is not always sufficient to determine which burn wounds will heal spontaneously and which will require surgical intervention for optimal outcome. We present a review of optical modalities currently in clinical use and under development to assist burn surgeons in assessing burn wound severity, including conventional histology/light microscopy, laser Doppler imaging, indocyanine green videoangiography, near-infrared spectroscopy and spectral imaging, in vivo capillary microscopy, orthogonal polarization spectral imaging, reflectance-mode confocal microscopy, laser speckle imaging, spatial frequency domain imaging, photoacoustic microscopy, and polarization-sensitive optical coherence tomography.
---
paper_title: Near-Infrared Fluorescent Materials for Sensing of Biological Targets

paper_content:

Near-infrared fluorescent (NIRF) materials are promising labeling reagents for sensitive determination and imaging of biological targets. In the near-infrared region biological samples have low background fluorescence signals, providing high signal to noise ratio. Meanwhile, near-infrared radiation can penetrate into sample matrices deeply due to low light scattering. Thus, in vivo and in vitro imaging of biological samples can be achieved by employing the NIRF probes. To take full advantage of NIRF materials in the biological and biomedical field, one of the key issues is to develop intense and biocompatible NIRF probes. In this review, a number of NIRF materials are discussed including traditional NIRF dye molecules, newly developed NIRF quantum dots and single-walled carbon nanotubes, as well as rare earth metal compounds. The use of some NIRF materials in various nanostructures is illustrated. The enhancement of NIRF using metal nanostructures is covered as well. The fluorescence mechanism and bioapplications of each type of the NIRF materials are discussed in details.
---
paper_title: Biliary physiology and disease: Reflections of a physician‐scientist

paper_content:

A review is presented of Gustav Paumgartner's five decades of research and practice in hepatology focusing on biliary physiology and disease. It begins with studies of the excretory function of the liver including hepatic uptake of indocyanine green, bilirubin, and bile acids. The implications of these studies for diagnosis and understanding of liver diseases are pointed out. From there, the path of scientific research leads to investigations of hepatobiliary bile acid transport and the major mechanisms of bile formation. The therapeutic effects of the hydrophilic bile acid, ursodeoxycholic acid, have greatly stimulated these studies. Although ursodeoxycholic acid therapy for dissolution of cholesterol gallstones and some other nonsurgical treatments of gallstones were largely superseded by surgical techniques, ursodeoxycholic acid is currently considered the mainstay of therapy of some chronic cholestatic liver diseases, such as primary biliary cirrhosis. The major mechanisms of action of ursodeoxycholic acid therapy in cholestatic liver diseases are discussed. An attempt is made to illustrate how scientific research can lead to advances in medical practice that help patients. (HEPATOLOGY 2010:51:1095–1106.)
---
paper_title: The clinical use of indocyanine green as a near-infrared fluorescent contrast agent for image-guided oncologic surgery.

paper_content:

Optical imaging using near-infrared (NIR) fluorescence provides new prospects for general and oncologic surgery. ICG is currently utilised in NIR fluorescence cancer-related surgery for three indications: sentinel lymph node (SLN) mapping, intraoperative identification of solid tumours, and angiography during reconstructive surgery. Therefore, understanding its advantages and limitations is of significant importance. Although non-targeted and non-conjugatable, ICG appears to be laying the foundation for more widespread use of NIR fluorescence-guided surgery.
---
paper_title: Indocyanine green angiography: a perspective on use in the clinical setting.

paper_content:

PURPOSE ::: To review the history of indocyanine green (ICG) angiography and to present a personal perspective on its use in the clinical setting today. ::: ::: ::: DESIGN ::: Perspective with literature review and opinions based on personal experience. ::: ::: ::: METHODS ::: To acquire views from international retinal physicians experienced with the technique on uses in their facilities and to compare them to the author's personal standards. ::: ::: ::: RESULTS ::: The author and contributing retinal physicians had surprisingly similar views for most, but not all, applications for ICG angiography use in the clinical setting. ::: ::: ::: CONCLUSIONS ::: ICG angiography is recommended for a few highly selective chorioretinal disorders, including certain forms of neovascularization in age-related macular degeneration, other neovascular maculopathies, chronic central serous chorioretinopathy, choroidal hemangiomas, and posterior uveitis.
---
paper_title: Emission and absorption properties of indocyanine green in Intralipid solution

paper_content:

Emission and absorption properties of indocyanine green (ICG) in Intralipid solution have been investigated. The study is focused on relatively low ICG concentration at a range of 0 to 20 μM. A diffusion model was used to analyze the emission properties of ICG solution at different concentrations. In the low-concentration region, the emission strength increases with the concentration of ICG, while in the high-concentration region, the emission decreases with the concentration. In general, a maximum of emission strength exists and its position (concentration) depends on the wavelength of the excitation light, the distance between the source and the detector, and the sample geometry and size. A so-called “inner-cell-effect” and re-absorption of emission photons are found to contribute to the decay of emission strength. Also, in the concentration range of 0 to 2 μM, ICG solution always has a higher absorption coefficient at wavelength 830 nm than that at 660 nm, which is quite different from the ICG in water case.
---
paper_title: New Technologies for Human Cancer Imaging

paper_content:

Despite technical advances in many areas of diagnostic radiology, the detection and imaging of human cancer remains poor. A meaningful impact on cancer screening, staging, and treatment is unlikely to occur until the tumor-to-background ratio improves by three to four orders of magnitude (ie, 103- to 104-fold), which in turn will require proportional improvements in sensitivity and contrast agent targeting. This review analyzes the physics and chemistry of cancer imaging and highlights the fundamental principles underlying the detection of malignant cells within a background of normal cells. The use of various contrast agents and radiotracers for cancer imaging is reviewed, as are the current limitations of ultrasound, x-ray imaging, magnetic resonance imaging (MRI), single-photon emission computed tomography, positron emission tomography (PET), and optical imaging. Innovative technologies are emerging that hold great promise for patients, such as positron emission mammography of the breast and spectrosco...
---
paper_title: Near-Infrared Dichromic Fluorescent Carbocyanine Molecules

paper_content:

Central to major advances in biochemical assays, molecularsensor technologies, and molecular optical imaging arefluorescent materials that provide high detection sensitivityformolecularprocesses.Inbiologicalopticalimaging,thelowtissueautofluorescenceandthedeeppenetrationoflightintothetissuesobservedatwavelengthsbetween650 and900nmallow the use of near-infrared (NIR) fluorescent dyes ascontrast agents in heterogeneous systems.
---
paper_title: Hands-free, wireless goggles for near-infrared fluorescence and real-time image-guided surgery.

paper_content:

BACKGROUND ::: Current cancer management faces several challenges, including the occurrence of a residual tumor after resection, the use of radioactive materials or high concentrations of blue dyes for sentinel lymph node biopsy, and the use of bulky systems in surgical suites for image guidance. To overcome these limitations, we developed a real-time, intraoperative imaging device that, when combined with near infrared fluorescent molecular probes, can aid in the identification of tumor margins, guide surgical resections, map sentinel lymph nodes, and transfer acquired data wirelessly for remote analysis. ::: ::: ::: METHODS ::: We developed a new compact, wireless, wearable, and battery-operated device that allows for hands-free operation by surgeons. A charge-coupled device-based, consumer-grade night vision viewer was used to develop the detector portion of the device, and the light source portion was developed from a compact headlamp. This piece was retrofitted to provide both near infrared excitation and white light illumination simultaneously. Wireless communication was enabled by integrating a battery-operated, miniature, radio-frequency video transmitter into the system. We applied the device in several types of oncologic surgical procedures in murine models, including sentinel lymph node mapping, fluorescence-guided tumor resection, and surgery under remote expert guidance. ::: ::: ::: RESULTS ::: Unlike conventional imaging instruments, the device displays fluorescence information directly on its eyepiece. When employed in sentinel lymph node mapping, the locations of sentinel lymph nodes were visualized clearly, even with tracer level dosing of a near infrared fluorescent dye (indocyanine green). When used in tumor resection, tumor margins and small nodules invisible to the naked eye were visualized readily. In a simulated, point-of-care setting, tumors were located successfully and removed under remote guidance using the wireless feature of the device. Importantly, the total cost of this prototype system ($1200) is substantially less than existing imaging instruments. ::: ::: ::: CONCLUSION ::: Our results demonstrate the feasibility of using the new device to aid surgical resection of tumors, map sentinel lymph nodes, and facilitate telemedicine.
---
paper_title: Stabilization of the Optical Tracer Agent Indocyanine Green Using Noncovalent Interactions

paper_content:

Abstract Indocyanine green is a medically useful dye that absorbs and fluoresces in the near infrared and has been sporadically employed clinically as an optical tracer agent for liver function evaluation and cardiac output measurements. The poor stability of this dye in aqueous solution, especially at the high concentrations needed for bolus injection, has been a hindrance in clinical application. However, by using carefully chosen macromolecular additives, the stability of these aqueous dye solutions may be enhanced significantly. Such noncovalent binding between dye and carrier molecules was found to preserve substantially the dye in aqueous solutions for several weeks with no apparent changes in the measured in vivo biological properties.
---
paper_title: Light-induced decomposition of indocyanine green.

paper_content:

PURPOSE ::: To investigate the light-induced decomposition of indocyanine green (ICG) and to test the cytotoxicity of light-induced ICG decomposition products. ::: ::: ::: METHODS ::: ICG in solution was irradiated with laser light, solar light, or surgical endolight. The light-induced decomposition of ICG was analyzed by high-performance liquid chromatography (HPLC) and mass spectrometry. Porcine retinal pigment epithelial (RPE) cells were incubated with the light-induced decomposition products of ICG, and cell viability was measured by trypan blue exclusion assay. ::: ::: ::: RESULTS ::: Independent of the light source used, singlet oxygen (photodynamic type 2 reaction) is generated by ICG leading to dioxetanes by [2+2]-cycloaddition of singlet oxygen. These dioxetanes thermally decompose into several carbonyl compounds. The decomposition products were identified by mass spectrometry. The decomposition of ICG was inhibited by adding sodium azide, a quencher of singlet oxygen. Incubation with ICG decomposition products significantly reduced the viability of RPE cells in contrast to control cells. ::: ::: ::: CONCLUSIONS ::: ICG is decomposed by light within a self-sensitized photo oxidation. The decomposition products reduce the viability of RPE cells in vitro. The toxic effects of decomposed ICG should be further investigated under in vivo conditions.
---
paper_title: Fluorescence of indocyanine green in blood: intensity dependence on concentration and stabilization with sodium polyaspartate.

paper_content:

Indocyanine green (ICG) has been widely used in cardiovascular, hepatic, and ophthalmologic studies. Application of this fluorescent dye has been handicapped by its poor stability in solution and by the complex dependence of its fluorescence intensity on concentration. Noncovalent interactions between ICG and sodium polyaspartate (PASP) stabilize ICG fluorescence in aqueous solution, but the effect of PASP on ICG fluorescence in blood has not been described. The current study had two main goals: first, to characterize in vitro in blood the relationship between fluorescence intensity and concentration of ICG-PASP (ICG) and the stability of this relationship over time; second, to test a new phenomenological model describing the dependence of ICG fluorescence on concentration. Freshly-prepared ICG and ICG-PASP solutions produced the same fluorescence intensity over a wide range of concentrations (0.0005-0.1271 mg/ml). The peak fluorescence of ICG was reduced by 11% after 10 h and by 72% at 7 days. In contrast, the peak fluorescence intensity of ICG-PASP solutions was nearly unchanged for up to 14 days. The dependence of the fluorescence intensity on concentration was accurately represented by our model that accounted for the generation of fluorescence following light absorption, and for the reabsorption of the emitted fluorescence by ICG.
---
paper_title: STEADY‐STATE NEAR‐INFRARED DETECTION OF SINGLET MOLECULAR OXYGEN: A STERN‐VOLMER QUENCHING EXPERIMENT WITH SODIUM AZIDE

paper_content:

Abstract— A sensitive near-infrared detection system incorporating improvements to existing methodologies has been used to characterize the sodium azide quenching of the steady-state luminescence of singlet molecular oxygen at 1270 nm. Stern-Volmer plots which were linear up to 80% quenching of the 1O2 generated by rose bengal and eosin Y yielded a rate constant of 5.8 ± 0.1 times 108M−1 s−1 for the quenching of 1O2 in water, while the rate constants obtained in deuterium oxide with the same sensitizers were 6.28 times 108M−1 s−1 and 6.91 times 108M−1 s−1 respectively. A flow system minimized the effects of photobleaching of the rose bengal. With a mercury arc light source, the instrument can be used in photosensitization experiments to detect low levels of 1O2 production in aqueous media.
---
paper_title: Indocyanine green: Intracellular uptake and phototherapeutic effects in vitro

paper_content:

Indocyanine green (ICG; absorption peak in human plasma 805 nm) was investigated for ICG-mediated phototherapy in vitro. The cellular uptake of ICG (1 microM-50 microM) into HaCaT keratinocytes after an incubation period of 24 h increased up to an intracellular ICG concentration of 12.1 +/- 1.3 nmol per 10(6) cells. To examine dose dependent phototoxic effects in vitro, keratinocytes were incubated with 0 microM-50 microM ICG for 24 h and irradiated by a diode laser (805 nm) with different energy densities (0, 12, 24, 48 J cm-2). All applied ICG concentrations except for 5 microM yielded a cell killing effect in combination with irradiation depending significantly on ICG concentration and light dose. Cell viability for dark control and cells incubated with 50 microM ICG and irradiated with 48 J cm-2 was 0.82 +/- 0.15 and 0.07 +/- 0.02, respectively. Sodium azide (100 mM), a quencher of reactive oxygen species, inhibited significantly the cell killing using 50 microM ICG and 24 J cm-2. Taken together, photoactivation of ICG by irradiation with a diode laser was shown to induce effectively cell killing of HaCaT keratinocytes. Moreover, this effect was inhibited by sodium azide, thus irradiation of ICG might induce a photodynamic reaction.
---
paper_title: Fluorescence spectroscopic analysis of indocyanine green J aggregates in water

paper_content:

Abstract Indocyanine green in water forms J aggregates, which are observed as a red-shifted narrow absorption band at 890 nm. The fluorescence quantum distribution of the indocyanine green J aggregates was studied by continuous wave laser excitation at 834 nm. A fluorescence quantum yield of Ф F ≈ 3 × 10 −4 was measured. The fluorescence peak coincides with the absorption peak (no Stokes shift).
---
paper_title: Light-absorbing properties, stability, and spectral stabilization of indocyanine green.

paper_content:

The absorption spectrum of indocyanine green depends on the nature of the solvent medium and on the dye concentration. Binding to plasma proteins causes the principal peaks in the absorption spectrum to shift about 25 nm toward the higher wavelengths. The much greater influence on the spectrum of the dye concentration results from progressive aggregate formation with increasing concentration. Indocyanine green solutions therefore do not follow Lambert-Beer's law above 15 mg-I-1 (in plasma). Indocyanine green solutions in plasma and concentrated (1,000 mg-I-1) solutions in distilled water are stable for at least 4 h. In long-term experiments the optical density of indocyanine green solutions in plasma as well as in distilled water generally diminishes, even in the dark. On the 7th day a new absorption maximum starts to appear at gamma=900 nm, possibly caused by further aggregate formation leading to much larger particles. Spectral stabilization after injection of a concentrated solution into the blood is most rapid when the dye is dissolved in distilled water. Spectral stabilization slows down with decreasing temperature. As rapid spectral stabilization is essential in quantitative dye dilution studies, the practice of adding a albumin and/or isotonic saline solution to the injectate should be discontinued. When a 10 g-1(-1) aqueous solution of indocyanine green is used, spectral stabilization takes less than 1.5 a (at 37 degrees C), which is sufficiently fast for almost any application.
---
paper_title: INVOLVEMENT OF ILLUMINATION IN INDOCYANINE GREEN TOXICITY AFTER ITS WASHOUT IN THE EX VIVO RAT RETINA

paper_content:

For half a century indocyanine green (ICG), a tricarbocyanine dye, has been used for angiography to assess cardiac and liver function. 1, 2 In ophthalmology, ICG has been used to evaluate the choroidal circulation 3 and has played a significant role in the diagnosis of chorioretinal disorders . 4-7 Because systemic adverse effects are rare, 8 ICG is thought to be safe when injected intravenously. ICG is also useful in staining the internal limiting membrane (ILM) of the retina for visualization during vitrectomy 9 and ICG is now routinely used in retinal surgeries for repair of macular holes 9, 10 and in epiretinal membrane surgeries.11 However, there remain clinical concerns about possible toxic effects of ICG on the retina following ICG-assisted vitrectomies. These toxic effects include poor functional outcomes, 12, 13 visual field defects 14-16 and retinal pigment epithelium degeneration.17, 18 ::: ::: Several measures have been used during vitrectomy to minimize the toxic effects of ICG. Although use of lower concentrations of ICG 19, 20 or irrigation immediately after ICG exposure 21, 22 limit the toxic actions, adverse effects on the retina following ICG exposure remain common, suggesting that these simple measures do not successfully minimize the toxicity.13, 23 ICG exposure during vitrectomy must be followed by intensive intraocular illumination which itself has long been speculated to be responsible for poor outcomes following vitrectomy.24, 25 Thus, we hypothesized that one of the toxic actions of ICG results from an interaction with illumination during or after ICG exposure. ::: ::: Phototoxicity in the retina is characterized by degeneration of photoreceptor cells in the outer nuclear layer (ONL).26-29 To assess layer-specific mechanisms involved in various forms of retinal injury, we have developed a mammalian ex vivo retinal preparation30 that allows detailed morphological assessment of changes in specific cell layers. We previously used this preparation to examine interactions of a phototoxic drug with illumination in producing retinal damage,31 and have found that the preparation is useful for studying phototoxic interactions. Morphological assessment is critical for understanding the effects of phototoxicity and for characterizing the adverse effects of ICG.32 In the present study we used a rat retinal preparation and observed that ICG has interactions with intensive illumination in inducing retinal damage. To quantify retinal damage, we combined morphological assessments with a biochemical assay measuring lactate dehydrogenase (LDH) released from injured cells. We also examined whether changes in incubation temperature altered ICG-mediated phototoxicity.
---
paper_title: Light-induced decomposition of indocyanine green.

paper_content:

PURPOSE ::: To investigate the light-induced decomposition of indocyanine green (ICG) and to test the cytotoxicity of light-induced ICG decomposition products. ::: ::: ::: METHODS ::: ICG in solution was irradiated with laser light, solar light, or surgical endolight. The light-induced decomposition of ICG was analyzed by high-performance liquid chromatography (HPLC) and mass spectrometry. Porcine retinal pigment epithelial (RPE) cells were incubated with the light-induced decomposition products of ICG, and cell viability was measured by trypan blue exclusion assay. ::: ::: ::: RESULTS ::: Independent of the light source used, singlet oxygen (photodynamic type 2 reaction) is generated by ICG leading to dioxetanes by [2+2]-cycloaddition of singlet oxygen. These dioxetanes thermally decompose into several carbonyl compounds. The decomposition products were identified by mass spectrometry. The decomposition of ICG was inhibited by adding sodium azide, a quencher of singlet oxygen. Incubation with ICG decomposition products significantly reduced the viability of RPE cells in contrast to control cells. ::: ::: ::: CONCLUSIONS ::: ICG is decomposed by light within a self-sensitized photo oxidation. The decomposition products reduce the viability of RPE cells in vitro. The toxic effects of decomposed ICG should be further investigated under in vivo conditions.
---
paper_title: Indocyanine green: Intracellular uptake and phototherapeutic effects in vitro

paper_content:

Indocyanine green (ICG; absorption peak in human plasma 805 nm) was investigated for ICG-mediated phototherapy in vitro. The cellular uptake of ICG (1 microM-50 microM) into HaCaT keratinocytes after an incubation period of 24 h increased up to an intracellular ICG concentration of 12.1 +/- 1.3 nmol per 10(6) cells. To examine dose dependent phototoxic effects in vitro, keratinocytes were incubated with 0 microM-50 microM ICG for 24 h and irradiated by a diode laser (805 nm) with different energy densities (0, 12, 24, 48 J cm-2). All applied ICG concentrations except for 5 microM yielded a cell killing effect in combination with irradiation depending significantly on ICG concentration and light dose. Cell viability for dark control and cells incubated with 50 microM ICG and irradiated with 48 J cm-2 was 0.82 +/- 0.15 and 0.07 +/- 0.02, respectively. Sodium azide (100 mM), a quencher of reactive oxygen species, inhibited significantly the cell killing using 50 microM ICG and 24 J cm-2. Taken together, photoactivation of ICG by irradiation with a diode laser was shown to induce effectively cell killing of HaCaT keratinocytes. Moreover, this effect was inhibited by sodium azide, thus irradiation of ICG might induce a photodynamic reaction.
---
paper_title: Indocyanine green videoangiography using cooled charge-coupled devices in central serous choroidopathy

paper_content:

In order to evaluate the use of low level light (LLL) indocyanine green angiography in the diagnosis and ::: treatment of central serous choroidopathy (CSC), a new system for LLL infrared videoangiography is described. The system was coupled with a standard fundus camera employing a low-power continuous light ::: source. The system consists of a cooled charge-coupled device (CCD) camera and a third-generation image intensifier. The CCD camera investigates the pathologies of choroidal images with very good performance in terms of spatial resolution, dynamic range, and signal-to-noise ratio. The image intensifier carries out the choroidal angiography in real time. The results of 48 cases of CSC demonstrated the following ICGV features: focal RPE leakage; hyperfluorescent areas appearing in late phases and underlying the focal leakage or pigment epithelium detachment (PED); PED in the guise of early hyperfluorescent areas; delays in choroidal ::: filling. The findings support the hypothesis that CSC originates in the choroid with localized hyperpermeability. The system described minimized retinal illumination and demonstrated increased angiographic resolution and contrast compared with conventional ICG angiographic systems.
---
paper_title: The interaction of indocyanine green dye with the human epidermis studied in vivo

paper_content:

A shift of the light wavelength corresponding to the optical absorption peak of Indocyanine Green used for staining the horny layer of the human epidermis was measured in vivo. It is established that the dye molecules occur in both free and chemically bound state at the skin surface and only in the bound state at a depth of ∼5 μ m.
---
paper_title: Binding properties of indocyanine green in human blood.

paper_content:

PURPOSE. Binding properties of indocyanine green (ICG) to human plasma proteins were identified using electrophoresis and a fundus video system. METHODS. Blood samples were obtained from three healthy volunteers after intravenous administration of ICG. The resulting plasma samples were fractionated by agarose gel immunoelectrophoresis and polyacrylamide gel DISC electrophoresis. In the former, antisera, antiapolipoprotein (Apo)-A, and anti-Apo-B antibodies were used to identify all classes of plasma proteins. high-density lipoprotein (HDL), and low-density lipoprotein (LDL), respectively. In the latter method, plasma samples could be separated into chylomicron, very low-density lipoprotein, LDL, and HDL. The electrophoretic pattern obtained by each method was observed with an ICG fundus video system. Furthermore, we studied the affinity of ICG for lipids that were common molecular components of HDL and LDL. Four kinds of ICG solutions mixed with phospholipid, free cholesterol, esterified cholesterol, and triacylglycerol were observed with the ICG fundus video system. RESULTS. Both electrophoretic studies showed that ICG bound intensely to HI)L and moderately to LDL, and only the solution with phospholipid fluoresced brightly, when observed with the ICG fundus video system. CONCLUSIONS. These findings indicated low vascular or tissue permeability of ICG, which is caused by the larger molecular size of HDL and LDL. Also noted was that the ICG fluorescence observed in the angiogram may be equivalent to the hemodynamics of HDL alone or in combination with LDL in the bloodstream. This biochemical consideration may be a basis for the further understanding of ICG angiography.
---
paper_title: The binding of indocyanine green and other organic anions to serum proteins in liver diseases.

paper_content:

Using Sephadex G-200 column chromatography, the binding patterns of organic anions with serum proteins were studied in normal subjects and in patients with liver diseases. BSP, [131I]BSP and [131I] Rose Bengal were bound mainly to albumin while small amounts were bound to globulin fractions. In normal sera, indocyanine green (ICG) in lower concentrations was bound mainly to β-lipoprotein while in higher concentrations it was bound to all fractions of proteins. In the various liver diseases, the binding patterns of ICG showed characteristic changes in comparison to those other organic anions. In acute hepatitis, obstructive jaundice and the Dubin-Johnson syndrome, the characteristic ICG peak II was decreased. In chronic liver diseases, such as chronic hepatitis and liver cirrhosis, the ICG peak II was increased remarkably and was bound to heavier proteins. Using single radial immunodiffusion and autoradiography, the binding of [131I]BSP with normal sera were studied. [131I] BSP was mainly to albumin, prealbumin and β-lipoprotein while small amounts were bound to the globulin fractions.
---
paper_title: Low-frequency wide-field fluorescence lifetime imaging using a high-power near-infrared light-emitting diode light source

paper_content:

Fluorescence lifetime imaging FLi could potentially im- prove exogenous near-infrared NIR fluorescence imaging, because it offers the capability of discriminating a signal of interest from back- ground, provides real-time monitoring of a chemical environment, and permits the use of several different fluorescent dyes having the same emission wavelength. We present a high-power, LED-based, NIR light source for the clinical translation of wide-field larger than 5c m in diameter FLi at frequencies up to 35 MHz. Lifetime imaging of indocyanine green ICG, IRDye 800-CW, and 3,3-diethylthiatricarbocyanine iodide DTTCI was performed over a large field of view 10 cm by 7.5 cm using the LED light source. For comparison, a laser diode light source was employed as a gold stan- dard. Experiments were performed both on the bench by diluting the fluorescent dyes in various chemical environments in Eppendorf tubes, and in vivo by injecting the fluorescent dyes mixed in Matrigel subcutaneously into CD-1 mice. Last, measured fluorescence lifetimes obtained using the LED and the laser diode sources were compared with those obtained using a state-of-the-art time-domain imaging sys- tem and with those previously described in the literature. On average, lifetime values obtained using the LED and the laser diode light sources were consistent, exhibiting a mean difference of 3% from the expected values and a coefficient of variation of 12%. Taken together, our study offers an alternative to laser diodes for clinical translation of FLi and explores the use of relatively low frequency modulation for in
---
paper_title: Accuracy of Noninvasive in vivo Measurements of Photosensitizer Uptake Based on a Diffusion Model of Reflectance Spectroscopy

paper_content:

Abstract— This study compares the photosensitizer concentration measured noninvasively in vivo by diffuse reflectance spectroscopy with the results of postmortem tissue solubilization and fluorometric assay. The reflectance spectrometer consists of a fiber optic surface probe, spectrometer and charge-coupled device (CCD) array detector. The surface probe has eight detection fibers separated from the light source fiber by distances ranging from 0.85 to 10 mm. The imaging spectrometer disperses the light from each detector fiber onto the two-dimensional CCD array, while maintaining spatial separation of each individual spectrum. A single exposure of the CCD therefore captures the reflectance spectrum at eight distances and over a range of 300 nm. From the spectra, the tissue's optical scattering and absorption coefficients are determined using a diffusion model of light propagation. Changes in the tissue absorption are used to estimate the photosensitizer concentration. Normal New Zealand White rabbits were injected with aluminum phthalocyanine tetrasulfonate (AlPcS4) and probe measurements made 24 h after injection on the dorsal skin, on muscle after surgically turning the skin back and on liver. For skin, the noninvasive estimate is proportional to the true concentration but low by a factor of 3. Based on Monte Carlo modeling of multilayered systems, this underestimate is attributed to the layered structure of the skin and nonuniform AIPcS4 distribution. A comparison of the noninvasive concentration estimates to the postmortem assay results finds good agreement for liver tissue even though application of the diffusion model is not strictly justified.
---
paper_title: Spectral characteristics of indocyanine Green upon its interaction with biological tissues

paper_content:

The changes in the absorption spectra of solutions of Indocyanine Green are studied in relation to the nature and composition of the solvent and the dye concentration. The reflection spectra from selected areas of human skin stained with different solutions of Indocyanine Green are studied in vivo upon successive stripping of stained surface epidermal layers. The reflection spectra from human hairs stained in vitro with an alcohol solution of Indocyanine Green are measured. It is shown that the shift of the absorption band maximum of Indocyanine Green determined by the interaction of the dye with epidermal or hair keratin does not depend on the solvent composition or the depth of location of the stained layer.
---
paper_title: Indocyanine green videoangiography using cooled charge-coupled devices in central serous choroidopathy

paper_content:

In order to evaluate the use of low level light (LLL) indocyanine green angiography in the diagnosis and ::: treatment of central serous choroidopathy (CSC), a new system for LLL infrared videoangiography is described. The system was coupled with a standard fundus camera employing a low-power continuous light ::: source. The system consists of a cooled charge-coupled device (CCD) camera and a third-generation image intensifier. The CCD camera investigates the pathologies of choroidal images with very good performance in terms of spatial resolution, dynamic range, and signal-to-noise ratio. The image intensifier carries out the choroidal angiography in real time. The results of 48 cases of CSC demonstrated the following ICGV features: focal RPE leakage; hyperfluorescent areas appearing in late phases and underlying the focal leakage or pigment epithelium detachment (PED); PED in the guise of early hyperfluorescent areas; delays in choroidal ::: filling. The findings support the hypothesis that CSC originates in the choroid with localized hyperpermeability. The system described minimized retinal illumination and demonstrated increased angiographic resolution and contrast compared with conventional ICG angiographic systems.
---
paper_title: The binding of indocyanine green and other organic anions to serum proteins in liver diseases.

paper_content:

Using Sephadex G-200 column chromatography, the binding patterns of organic anions with serum proteins were studied in normal subjects and in patients with liver diseases. BSP, [131I]BSP and [131I] Rose Bengal were bound mainly to albumin while small amounts were bound to globulin fractions. In normal sera, indocyanine green (ICG) in lower concentrations was bound mainly to β-lipoprotein while in higher concentrations it was bound to all fractions of proteins. In the various liver diseases, the binding patterns of ICG showed characteristic changes in comparison to those other organic anions. In acute hepatitis, obstructive jaundice and the Dubin-Johnson syndrome, the characteristic ICG peak II was decreased. In chronic liver diseases, such as chronic hepatitis and liver cirrhosis, the ICG peak II was increased remarkably and was bound to heavier proteins. Using single radial immunodiffusion and autoradiography, the binding of [131I]BSP with normal sera were studied. [131I] BSP was mainly to albumin, prealbumin and β-lipoprotein while small amounts were bound to the globulin fractions.
---
paper_title: Effects of caloric restriction on the kinetics of indocyanine green in patients with liver diseases and in the rat

paper_content:

The effect of caloric restriction on the hepatic uptake and excretion of indocyanine green (ICG) was studied in man as well as in rats. It was demonstrated that following a 72-hr caloric restriction in man, the plasma clearance rate for ICG was increased significantly at the low dose of 0.5 mg/kg, and transport maximum was increased without a significant change of storage capacity. In rats, the maximal biliary excretion was significantly increased after 48-hr fast, but neither maximal hepatic uptake (Vmax) nor hepatic ICG content was altered. The evidence is consistent with the view that fasting increases the ICG plasma clearance at low doses by enhancement of excretory steps at the bile canalicular membrane.
---
paper_title: Light-induced decomposition of indocyanine green.

paper_content:

PURPOSE ::: To investigate the light-induced decomposition of indocyanine green (ICG) and to test the cytotoxicity of light-induced ICG decomposition products. ::: ::: ::: METHODS ::: ICG in solution was irradiated with laser light, solar light, or surgical endolight. The light-induced decomposition of ICG was analyzed by high-performance liquid chromatography (HPLC) and mass spectrometry. Porcine retinal pigment epithelial (RPE) cells were incubated with the light-induced decomposition products of ICG, and cell viability was measured by trypan blue exclusion assay. ::: ::: ::: RESULTS ::: Independent of the light source used, singlet oxygen (photodynamic type 2 reaction) is generated by ICG leading to dioxetanes by [2+2]-cycloaddition of singlet oxygen. These dioxetanes thermally decompose into several carbonyl compounds. The decomposition products were identified by mass spectrometry. The decomposition of ICG was inhibited by adding sodium azide, a quencher of singlet oxygen. Incubation with ICG decomposition products significantly reduced the viability of RPE cells in contrast to control cells. ::: ::: ::: CONCLUSIONS ::: ICG is decomposed by light within a self-sensitized photo oxidation. The decomposition products reduce the viability of RPE cells in vitro. The toxic effects of decomposed ICG should be further investigated under in vivo conditions.
---
paper_title: Pulse Dye Densitometry and Indocyanine Green Plasma Disappearance in ASA Physical Status I-II Patients

paper_content:

BACKGROUND: Indocyanine green plasma disappearance rate (ICG-PDR) is used to evaluate hepatic function. Although hepatic failure is generally said to occur with an ICG-PDR 18%/min, ICG disappearance rate is poorly defined in the healthy population, and a clear cutoff value of ICG-PDR that discriminates between normal hepatic function and hepatic failure has not yet been described. We therefore defined the ICG disappearance rate in an otherwise healthy patient population. In addition, we evaluated the noninvasive measurement of ICG-PDR (transcutaneously by pulse dye densitometry [PDD] at the finger and the nose) and compared these with the simultaneously performed invasive measurements of ICG-PDR (in arterial blood). METHODS: In patients without signs of liver disease, scheduled for elective nonhepatic surgery, 10 mg ICG was administered IV and ICG-PDR measured by PDD (DDG-2001, Nihon Kohden, Tokyo, Japan). In a subset of patients, arterial blood samples were gathered to compare PDD with invasive ICG measurements. Methods were compared using Bland-Altman analysis. The results of our study and reported studies on discriminative use of ICG-PDR in assessing liver failure were used to construct receiver operating characteristic curves. RESULTS: Forty-one patients were studied: 33 using the finger probe and 8 using the nose probe. The mean sd noninvasive ICG-PDR in this patient population is 23.1% 7.9%/min (n 41) with a range of 9.7% to 43.2%/min. Bias (2 sd, limits of agreement) for ICG-PDR measured by PDD compared with those measured in arterial blood were 1.6%/min (5.2% to 8.3%/min) for the finger probe and 6.0%/min (15.5% to 3.4%/min) for the nose probe. CONCLUSION: ICG-PDR values in a population without liver failure ranged well below 18%/min, cited as the cutoff value for hepatic failure. This cutoff value needs reconsideration. In addition, we conclude that the ICG concentration is adequately determined noninvasively by PDD. (Anesth Analg 2010;110:466‐72)
---
paper_title: Indocyanine green videoangiography to detect aneurysm and related vascular structures buried in subarachnoid clots.

paper_content:

This 44-year-old woman presented with a ruptured anterior communicating artery aneurysm. Intraoperative indocyanine green (ICG) videoangiography demonstrated the aneurysm neck and dome, which were buried in subarachnoid clots. Dissection and aspiration of the clots around the neck were safely performed without touching the ruptured points. The aneurysm was successfully clipped. The patient's postoperative course was excellent. This case illustrates the use of intraoperative ICG videoangiography to provide information about the anatomical location of the aneurysm neck and dome despite their being completely obscured by subarachnoid clots. Intraoperative ICG videoangiography allowed safer dissection of the ruptured aneurysm from the blood clots.
---
paper_title: The use of indocyanine green videoangiography to optimize the dural opening for intracranial parasagittal lesions.

paper_content:

BACKGROUND ::: We describe our clinical experience with the use of indocyanine green (ICG) videoangiography to delineate the locations of the cortical draining veins before dural opening in 3 cases of parasagittal lesions. With this technique, the veins are marked through the dura, and then the dura can be opened precisely to avoid cortical venous injury. ::: ::: ::: OBJECTIVE ::: To demonstrate in a clinical series the adjunct use of intraoperative ICG angiography to optimize the dural opening for parasagittal lesions. ::: ::: ::: METHODS ::: We describe 3 cases of parasagittal lesions, 2 meningiomas, and 1 arteriovenous malformation treated using the described technique. ::: ::: ::: RESULTS ::: Once the dura had been exposed, ICG at a dose of 0.25 mg/kg was injected into the patient's peripheral vein as a bolus. When the dye reached the illuminated field of interest, ICG fluorescence was induced by the use of a light source with a wave-length ICG absorption band. Thereafter, the dural cortical veins were marked through the dura and precisely opened, avoiding cortical venous injury. ::: ::: ::: CONCLUSION ::: Indocyanine green video angiography is a safe, fast, inexpensive, and accurate investigation that allows the surgeon to strategically plan and protect important parasagittal dural venous drainage during craniotomy.
---
paper_title: Influence of adipose tissue thickness on near infrared spectroscopic signal in the measurement of human muscle

paper_content:

The aim of this study was to clarify the influence of subcutaneous adipose tissue (AT) thickness on nearinfrared (NIR) optical density and the penetration depth of light in muscle tissue in vivo. The thickness of adipose tissue in the leg was measured using ultrasonography in 12 young subjects. Optical densities (OD) at 775, 807, and 827 nm were measured when the distance between the light source and the detector was increased from 20 to 100 mm in 10 mm steps. Ultrasonography showed that AT thickness ranged from 4 to 10 mm. The OD increased with increasing distance between the light source and the detector in all subjects. At the same distance between the light source and the detector (30 mm), the OD values correlated negatively with AT thickness (r 5 20.79, −0.82, and −0.79 at 775, 807, and 827 nm, respectively). Ultrasonography also showed that only the extensor hallucis longus muscle (EHL), which is under the extensor digitrum longus muscle (EDL), was activated during the flexion of the big toe. In order to evaluate the penetration depth of NIR light, the depth of EHL was measured and the OD observed before and during flexion. When the distance between the light source and detector was set at 30 mm, the OD values before exercise ranged from 0.36 to 3.18 at 775 nm, from 0.19 to 2.43 at 807 nm, and from 0.15 to 1.60 at 827 nm. Changes in OD during exercise were detectable for all subjects, and the EHLs of the subjects were located 10.0 to 20.2 mm under the ::: detector. However, when the light source-detector distance was set at 20 mm, changes in OD during exercise were detectable for only 2 subjects, whose AT thicknesses were 4.0 or 5.0 mm, and the EHLs of the subjects were 10.0 or 11.7 mm deep. At a distance of 40 mm, 9 out of 12 subjects showed changes in OD, and their AT thicknesses and EHL locations ranged from 6.4 to 10.0 mm and from 11.4 to 20.4 mm deep, respectively...
---
paper_title: Tissue Optics: Light Scattering Methods and Instruments for Medical Diagnosis

paper_content:

This third edition of the biomedical optics classic Tissue Optics covers the continued intensive growth in tissue optics-in particular, the field of tissue diagnostics and imaging-that has occurred since 2007. As in the first two editions, Part I describes fundamentals and basic research, and Part II presents instrumentation and medical applications. However, for the reader's convenience, this third edition has been reorganized into 14 chapters instead of 9. The chapters covering optical coherence tomography, digital holography and interferometry, controlling optical properties of tissues, nonlinear spectroscopy, and imaging have all been substantially updated. The book is intended for researchers, teachers, and graduate and undergraduate students specializing in the physics of living systems, biomedical optics and biophotonics, laser biophysics, and applications of lasers in biomedicine. It can also be used as a textbook for courses in medical physics, medical engineering, and medical biology.
---
paper_title: Morphologic and Clinical Effects of Subretinal Injection of Indocyanine Green and Infracyanine Green in Rabbits

paper_content:

Purpose: The aim of this study was to determine the effects of subretinal injection of indocyanine green (ICG), infracyanine (IfCG), and balanced salt solution (BSS) in rabbits. Methods: Ten (10) animals were subjected to a subretinal injection of 0.05% ICG (279 mOsm), 0.5% IfCG (276 mOsm), and BSS (300 mOsm) used as a control. Animals were examined at 6, 12, and 24 h and 14 days following the surgical procedure by indirect binocular ophthalmoscopy, fluorescein angiography (FA), and light and transmission electron microscopy. Results: The subretinal injection of ICG caused damage to all retinal layers and retinal pigment epithelium (RPE) during the entire follow-up. Subretinal injection of IfCG resulted in abnormalities of the photoreceptor outer segments (POSs) during the entire follow-up; however, abnormalities of the photoreceptor inner segments (PISs) and outer nuclear layer (ONL) were observed only 24 h and 14 days after surgery; no RPE damage was observed. FA showed that window defects were more pro...
---
paper_title: Bioconjugation of calcium phosphosilicate composite nanoparticles for selective targeting of human breast and pancreatic cancers in vivo.

paper_content:

The early diagnosis of cancer is the critical element in successful treatment and long-term favorable patient prognoses. The high rate of mortality is mainly attributed to the tendency for late diagnoses as symptoms may not occur until the disease has metastasized, as well as the lack of effective systemic therapies. Late diagnosis is often associated with the lack of timely sensitive imaging modalities. The promise of nanotechnology is presently limited by the inability to simultaneously seek, treat, and image cancerous lesions. This study describes the design and synthesis of fluorescent calcium phosphosilicate nanocomposite particles (CPNPs) that can be systemically targeted to breast and pancreatic cancer lesions. The CPNPs are a approximately 20 nm diameter composite composed of an amorphous calcium phosphate matrix doped with silicate in which a near-infrared imaging agent, indocyanine green (ICG), is embedded. In the present studies, we describe and validate CPNP bioconjugation of human holotransferrin, anti-CD71 antibody, and short gastrin peptides via an avidin-biotin or a novel PEG-maleimide coupling strategy. The conjugation of biotinylated human holotransferrin (diferric transferrin) and biotinylated anti-CD71 antibody (anti-transferrin receptor antibody) to avidin-conjugated CPNPs (Avidin-CPNPs) permits targeting of transferrin receptors, which are highly expressed on breast cancer cells. Similarly, the conjugation of biotinylated pentagastrin to Avidin-CPNPs and decagastrin (gastrin-10) to PEG-CPNPs via PEG-maleimide coupling permits targeting of gastrin receptors, which are overexpressed in pancreatic cancer lesions. These bioconjugated CPNPs have the potential to perform as a theranostic modality, simultaneously enhancing drug delivery, targeting, and imaging of breast and pancreatic cancer tumors.
---
paper_title: Ligand conjugated low-density lipoprotein nanoparticles for enhanced optical cancer imaging in vivo.

paper_content:

LDL particles are high-capacity nanocarriers with precisely controlled size and are naturally biocompatible, biodegradable, and nonimmunogenic. However, their utilities as drug carriers are limited by the narrow purview of LDL receptor-positive tumors. Here, we synthsized a ligand-conjugated, NIR-labeled LDL that enables the first in vivo demonstration of rerouting LDL from LDL receptors to selected alternate receptors, thus drastically expanding the range of using LDL particles as nanocarriers for in vivo cancer imaging and treatment.
---
paper_title: Folate-Polyethylene Glycol Conjugated Near-Infrared Fluorescence Probe with High Targeting Affinity and Sensitivity for In Vivo Early Tumor Diagnosis

paper_content:

PURPOSE ::: The purpose of this study is to synthesize a folate-polyethylene glycol (PEG) conjugated near-infrared fluorescence probe (fPI-01) for diagnosis of folate receptor (FR)-overexpressed tumors with high sensitivity and specificity. ::: ::: ::: PROCEDURES ::: fPI-01 was synthesized, purified, and characterized. Its cytotoxicity and affinity to tumor cells were determined in vitro. The dynamics and biodistribution of the probe was monitored in normal nude mice. And the tumor-targeting capability was investigated in nude mice bearing different tumor xenograft. ::: ::: ::: RESULTS ::: fPI-01 was successfully synthesized with strengthened optical properties. Cells experiments showed the probe had high FR affinity and without apparent cytotoxicity. Animal experiments indicated the probe excreted through urine by kidney. And its tumor-targeting ability was demonstrated on different tumor-bearing mice, with high sensitivity and tumor-to-normal tissue contrast ratio (10:1). ::: ::: ::: CONCLUSIONS ::: fPI-01 is a promising optical agent for diagnosis of FR-positive tumors, especially in their early stage.
---
paper_title: Double vital staining using trypan blue and infracyanine green in macular pucker surgery

paper_content:

Aims: To study the clinical properties of double vital staining in premacular fibrosis, facilitating complete removal of all epiretinal tissue. ::: ::: Methods: In a two step surgery, the epiretinal pucker was removed after staining with trypan blue, whereafter the inner limiting membrane was peeled after staining with infracyanine green. ::: ::: Results: In all 30 patients, a separate epiretinal layer and inner limiting membrane were removed from the macular area. Pathological examination showed different histological properties of the removed layers. An increased visual acuity was measured in 26 patients, and a slightly decreased visual acuity in one patient. ::: ::: Conclusion: The described double staining technique could be a novel valuable tool that may help to achieve optimal anatomical and functional recovery after surgery for premacular fibrosis
---
paper_title: Encapsulation and stabilization of indocyanine green within poly(styrene-alt-maleic anhydride) block-poly(styrene) micelles for near-infrared imaging.

paper_content:

Indocyanine green (ICG) is a Federal Drug Administration-approved near-infrared imaging agent susceptible to chemical degradation, nonspecific binding to blood proteins, and rapid clearance from the body. In this study, we describe the encapsulation of ICG within polymeric micelles formed from poly(styrene-alt-maleic anhydride)-block-poly(styrene) (PSMA-b-PSTY) diblock copolymers to stabilize ICG for applications in near-infrared diagnostic imaging. In aqueous solution, the diblock copolymers self-assemble to form highly stable micelles approximately 55 nm in diameter with a critical micelle concentration (CMC) of approximately 1 mg/L. Hydrophobic ICG salts readily partition into the PSTY core of these micelles with high efficiency, and produce no change in micelle morphology or CMC. Once loaded in the micelle core, ICG is protected from aqueous and thermal degradation, with no significant decrease in fluorescence emission over 14 days at room temperature and retaining 63% of its original emission at 37 degrees C. Free ICG does not release rapidly from the micelle core, with only 11% release over 24 h. The ICG-loaded micelles do not exhibit significant cell toxicity. This system has the potential to greatly improve near-infrared imaging in breast cancer detection by increasing the stability of ICG for formulation/administration, and by providing a means to target ICG to tumor tissue.
---
paper_title: Stabilization of indocyanine green by encapsulation within micellar systems.

paper_content:

Indocyanine green (ICG) is a fluorescence dye that is widely used for near-infrared imaging. Application of this dye is limited by its numerous disadvantageous properties in aqueous solution, including its concentration-dependent aggregation, poor aqueous stability in vitro and low quantum yield. Additionally, ICG is highly bound to nonspecific plasma proteins, leading to rapid elimination from the body with a half-life of 3-4 min. In this study, encapsulation of ICG within various micellar systems was investigated with the aim of overcoming these limitations. The aggregation behavior of different aqueous ICG formulations was studied using cryogenic transmission electron microscopy (cryo-TEM) and absorption spectroscopy. The micellar systems were characterized by their optical properties, particle size distribution, zeta potential and hemolytic activity. Encapsulation efficiency was determined using analytical ultracentrifugation. The best results were achieved for ICG encapsulated within aqueous Solutol HS 15 micelles. This formulation exhibited a lower aggregation behavior, a 3-fold increased quantum yield and high aqueous stability (over 4 weeks) compared to free aqueous ICG. The micelles were found to have an average diameter of 12 nm and a zeta potential close to zero (-2.1 +/- 1.7 mV). Encapsulation efficiency of ICG was high at 95%. The formulation did not display significant hemolytic activity. Consequently, Solutol HS 15 micelles are suitable nanocarriers for ICG which improve the optical properties and stability of the dye.
---
paper_title: Light-Absorbing Properties and Osmolarity of Indocyanine-Green Depending on Concentration and Solvent Medium

paper_content:

PURPOSE. To evaluate the absorption spectrum and osmolarity of three currently used indocyanine green (ICG) products at different concentrations and with different solvent media. METHODS. The absorption spectrum and osmolarity of three different ICG products (Pulsion, Munich, Germany; Akorn, Buffalo Grove, IL; and Laboratoires SERB, Paris, France) were analyzed. Each ICG was further diluted with balanced salt solution or glucose 5%. Four different concentrations were evaluated: 0.005%, 0.0025%, 0.001%, and 0.00025%. ICG (Pulsion) diluted in viscoelastic material (Healon; Pharmacia, Stockholm, Sweden) was analyzed at a concentration of 0.0025%. The following parameters were measured: absorption spectrum between 400 and 1000 nm, osmolarity, and the emission spectrum of the light source of a commonly used vitrectomy machine (Megatron; Geuder, Heidelberg, Germany). RESULTS. Independent from the manufacturer, concentrations of 0.005%, 0.0025%, and 0.001% ICG diluted in balanced salt solutions (BSS and BSS Plus; Alcon Pharmaceuticals, Fort Worth, TX) and glucose 5% showed two maxima, one at approximately 700 nm and a second one at 780 nm. There was an increase from zero to maximum absorption between 600 and 700 nm and a return to zero between 800 and 900 nm. The absorption band of ICG diluted in the viscoelastic material was similar to the saline solution (BSS or BSS Plus)-diluted ICG. At lower concentrations of 0.001% or 0.00025%, the peak at 700 nm decreased, forming a shoulder in the curve, whereas the peak at 780 nm remained stable. Osmolarity was in the range of 302 to 313 mOsM for BSS Plus-diluted ICG. When glucose 5% was used for ICG dilution, absorption between 600 and 700 nm decreased, and osmolarity was lower (between 292 and 298 mOsM). The light source emission was between 380 and 760 nm. CONCLUSIONS. Dilution of ICG using the balanced salt solutions BSS or BSS Plus resulted in a steep increase of absorption starting at 600 nm. In clinical practice, there is an overlap between the absorption band of ICG and the emission curve of the light source, resulting in a possible photosensitizing effect, especially at higher ICG concentrations. This effect becomes less likely with decreasing ICG concentrations or when glucose 5% is used as a solvent medium.
---
paper_title: Bright fluorescent nanoparticles for developing potential optical imaging contrast agents

paper_content:

Fluorescent cross-linked nanoparticles with variable fluorophore loading amounts, locations, and particle sizes were synthesized from sequential one-pot functionalization/cross-linking of block copolymer micelles with amine-terminated dye and cross-linker molecules, via reductive amination and amidation. The fluorescence quantum yield and brightness of these nanoparticles were evaluated by steady-state and dynamic fluorescence methods. The results demonstrate that the quantum yield and brightness of the fluorescent nanoparticles correlated directly with the number of dyes/nanoparticle and the nanoparticle size. A strategy to increase the fluorescence brightness of nanoparticles with fluorescein and near-infrared dyes is proposed.
---
paper_title: In vivo Molecular Imaging of Cancer with a Quenching Near-Infrared Fluorescent Probe Using Conjugates of Monoclonal Antibodies and Indocyanine Green

paper_content:

Near-infrared (NIR) fluorophores have several advantages over visible fluorophores, including improved tissue penetration and lower autofluorescence; however, only indocyanine green (ICG) is clinically approved. Its use in molecular imaging probes is limited because it loses its fluorescence after protein binding. This property can be harnessed to create an activatable NIR probe. After cell binding and internalization, ICG dissociates from the targeting antibody, thus activating fluorescence. ICG was conjugated to the antibodies daclizumab (Dac), trastuzumab (Tra), or panitumumab (Pan). The conjugates had almost no fluorescence in PBS but became fluorescent after SDS and 2-mercaptoethanol, with a quenching capacity of 10-fold for 1:1 conjugates and 40- to 50-fold for 1:5 conjugates. In vitro microscopy showed activation within the endolysosomes in target cells. In vivo imaging in mice showed that CD25-expressing tumors were specifically visualized with Dac-ICG. Furthermore, tumors overexpressing HER1 and HER2 were successfully characterized in vivo by using Pan-ICG(1:5) and Tra-ICG(1:5), respectively. Thus, we have developed an activatable NIR optical probe that “switches on” only in target cells. Because both the antibody and the fluorophore are Food and Drug Administration approved, the likelihood of clinical translation is improved. [Cancer Res 2009;69(4):1268–72]
---
paper_title: Endoscopic ICG perfusion imaging for flap transplants: technical development

paper_content:

Objective: Following tumour surgery in the head and neck region, skin flap transplants are usually required to cover the resection area. The purpose of the development was to provide a simple and reliable means to assess whether the transplanted flap is sufficiently perfused. Methods: Fluorescence of intravenously injected Indocyanine green (ICG) was detected with a slightly modified 3-chip CCD camera. Appropriately coated optical filters allow for excitation of ICG with NIR light and detection of NIR ICGfluorescence with the blue channel of the camera. In addition, low intensities of white light can be transmitted to allow for simultaneous display of a remission image in the green and red channels of the camera. Further processing was performed with a LabVIEW program. Results: A satisfactory white light image (red, green and blue display (RGB)) could be calculated from the remission images recorded with the green and red channels of the camera via a look-up table. The look-up table was programmed to provide an optimized blue intensity value for each combination of red and green values. This was generated using a reference image. Implementation of image tracking and intensity measurements in regions of interest (ROIs) in the images is useful to reliably monitor perfusion kinetics of flap and adjacent normal tissue.
---
paper_title: An Operational Near-Infrared Fluorescence Imaging System Prototype for Large Animal Surgery

paper_content:

Near-infrared (NIR) fluorescence imaging has the potential to revolutionize human cancer surgery by providing sensitive, specific, and real-time intraoperative visualization of normal and disease processes. We have previously introduced the concept of a low-cost, safe, and easy-to-use NIR fluorescence imaging system that permits the surgeon to "see" surgical anatomy and NIR fluorescence simultaneously, non-invasively, with high spatial resolution, in real-time, and without moving parts. In this study, we present an operational prototype designed specifically for use during large animal surgery. Such a system serves as a foundation for future clinical studies. We discuss technical considerations, and provide details of the implementation of subsystems related to excitation light, light collection, computer, and software. Using the prototype, and the clinically available NIR fluorophore indocyanine green, we demonstrate vascular imaging in 35 kg pigs. Cancer-specific applications of this imaging system include image-guided cancer resection with real-time assessment of surgical margins, image-guided sentinel lymph node mapping, intraoperative mapping of tumor and normal vasculature, image-guided avoidance of critical structures such as nerves, and intraoperative detection of occult metastases in the surgical field. Taken together, this study describes an optical imaging system engineered for eventual translation to the clinic.
---
paper_title: Robust Pairwise Registration for Images of Indocyanine-Green Angiographic Sequences

paper_content:

Motivated by the need of information integration from different image modalities for treatment of ocular diseases, this paper introduces an algorithm that registers image pairs from a complete IndoCyanine green angiography (ICG),containing Infra-Red (IR) and ICG images, for diagnosis of diseases in the choroidal layer, such as exudative senile macular degeneration. Challenges of the work include low image quality due to the presence of the Pigmented Retinal Epithelium and substantial appearance differences between images of different phases due to the circulation of the dye. Improved upon our previous work, Edge-Driven DBICP, with the focus on the image properties of an ICG sequence, our algorithm extracts features for registration from images with enhanced vessels to reduce the effect of the noise. For registration, Lowe keypoint matches for initialization are rank ordered by both distance and saliency measures and transformations are refined, going from local and low-order to global and higher-order model, in succession. Our dataset consists of 62 randomly-selected, pathological ICG sequences, each on average having up to two IR images and 12 ICG images. Our method successfully registered 83.4% of IR-ICG pairs, 89.7% of ICG-ICG pairs, and 86.37% of all pairs, which are about 49.3%, 25.5%, and 30.7% improvement, respectively, over Edge-Driven DBICP.
---
paper_title: Medical image registration

paper_content:

Radiological images are increasingly being used in healthcare and medical research. There is, consequently, widespread interest in accurately relating information in the different images for diagnosis, treatment and basic science. This article reviews registration techniques used to solve this problem, and describes the wide variety of applications to which these techniques are applied. Applications of image registration include combining images of the same subject from different modalities, aligning temporal sequences of images to compensate for motion of the subject between scans, image guidance during interventions and aligning images from multiple subjects in cohort studies. Current registration algorithms can, in many cases, automatically register images that are related by a rigid body transformation (i.e. where tissue deformation can be ignored). There has also been substantial progress in non-rigid registration algorithms that can compensate for tissue deformation, or align images from different subjects. Nevertheless many registration problems remain unsolved, and this is likely to continue to be an active field of research in the future.
---
paper_title: Quantitative imaging of lymph function

paper_content:

Functional lymphatic imaging was demonstrated in the abdomen and anterior hindlimb of anesthetized, intact Yorkshire swine by using near-infrared (NIR) fluorescence imaging following intradermal administration of 100–200 μl of 32 μM indocyanine green (ICG) and 64 μM hyaluronan NIR imaging conjugate to target the lymph vacular endothelial receptor (LYVE)-1 on the lymph endothelium. NIR fluorescence imaging employed illumination of 780 nm excitation light (∼2 mW/cm2) and collection of 830 nm fluorescence generated from the imaging agents. Our results show the ability to image the immediate trafficking of ICG from the plexus, through the vessels and lymphangions, and to the superficial mammary, subiliac, and middle iliac lymph nodes, which were located as deep as 3 cm beneath the tissue surface. “Packets” of ICG-transited lymph vessels of 2–16 cm length propelled at frequencies of 0.5–3.3 pulses/min and velocities of 0.23–0.75 cm/s. Lymph propulsion was independent of respiration rate. In the case of the hya...
---
paper_title: Imaging of lymph flow in breast cancer patients after microdose administration of a near-infrared fluorophore: feasibility study.

paper_content:

PURPOSE ::: To prospectively demonstrate the feasibility of using indocyanine green, a near-infrared (NIR) fluorophore at the minimum dose needed for noninvasive optical imaging of lymph nodes (LNs) in breast cancer patients undergoing sentinel lymph node mapping (SLNM). ::: ::: ::: MATERIALS AND METHODS ::: Informed consent was obtained from 24 women (age range, 30-85 years) who received intradermal subcutaneous injections of 0.31-100 microg indocyanine green in the breast in this IRB-approved, HIPAA-compliant, dose escalation study to find the minimum microdose for imaging. The breast, axilla, and sternum were illuminated with NIR light and the fluorescence generated in the tissue was collected with an NIR-sensitive intensified charged-coupled device. Lymphoscintigraphy was also performed. Resected LNs were evaluated for the presence of radioactivity, blue dye accumulation, and fluorescence. The associations between the resected LNs that were fluorescent and (a) the time elapsed between NIR fluorophore administration and resection and (b) the dosage of NIR fluorophores were tested with the Spearman rank and Pearson product moment correlation tests, respectively. ::: ::: ::: RESULTS ::: Lymph imaging consistently failed with indocyanine green microdosages between 0.31 and 0.77 microg. When indocyanine green dosages were 10 microg or higher, lymph drainage pathways from the injection site to LNs were imaged in eight of nine women; lymph propulsion was observed in seven of those eight. When propulsion in the breast and axilla regions was present, the mean apparent velocities ranged from 0.08 to 0.32 cm/sec, the time elapsed between "packets" of propelled fluid varied from 14 to 92 seconds. In patients who received 10 microg of indocyanine green or more, a weak negative correlation between the fluorescence status of resected LNs and the time between NIR fluorophore administration and LN resection was found. No statistical association was found between the fluorescence status of resected LNs and the dose of NIR fluorophore. ::: ::: ::: CONCLUSION ::: NIR fluorescence imaging of lymph function and LNs is feasible in humans at microdoses that would be needed for future molecular imaging of cancer-positive LNs.
---
paper_title: Fluorescence properties of indocyanine green as related to angiography

paper_content:

The fluorescence spectrum was measured as a function of dye concentration in human whole blood and a few other common solvents in order to determine what fluorescence properties are unique to indocyanine green in blood.
---
paper_title: New closed-form approximation for skin chromophore mapping.

paper_content:

The concentrations of blood and melanin in skin can be estimated based on the reflectance of light. Many models for this estimation have been built, such as Monte Carlo simulation, diffusion models, and the differential modified Beer-Lambert law. The optimization-based methods are too slow for chromophore mapping of high-resolution spectral images, and the differential modified Beer-Lambert is not often accurate enough. Optimal coefficients for the differential Beer-Lambert model are calculated by differentiating the diffusion model, optimized to the normal skin spectrum. The derivatives are then used in predicting the difference in chromophore concentrations from the difference in absorption spectra. The accuracy of the method is tested both computationally and experimentally using a Monte Carlo multilayer simulation model, and the data are measured from the palm of a hand during an Allen's test, which modulates the blood content of skin. The correlations of the given and predicted blood, melanin, and oxygen saturation levels are correspondingly r = 0.94, r = 0.99, and r = 0.73. The prediction of the concentrations for all pixels in a 1-megapixel image would take ∼ 20 min, which is orders of magnitude faster than the methods based on optimization during the prediction.
---
paper_title: A diffusion theory model of spatially resolved, steady‐state diffuse reflectance for the noninvasive determination of tissue optical properties in vivo

paper_content:

A model based upon steady-state diffusion theory which describes the radial dependence of diffuse reflectance of light from tissues is developed. This model incorporates a photon dipole source in order to satisfy the tissue boundary conditions and is suitable for either refractive index matched or mismatched surfaces. The predictions of the model were compared with Monte Carlo simulations as well as experimental measurements made with tissue simulating phantoms. The model describes the reflectance data accurately to radial distances as small as 0.5 mm when compared to Monte Carlo simulations and agrees with experimental measurements to distances as small as 1 mm. A nonlinear least-squares fitting procedure has been used to determine the tissue optical properties from the radial reflectance data in both phantoms and tissues in vivo. The optical properties derived for the phantoms are within 5%–10% of those determined by other established techniques. The in vivo values are also consistent with those reported by other investigators.
---
paper_title: Absorption and fluorescence spectroscopic investigation of indocyanine green

paper_content:

Abstract Absorption spectra, fluorescence quantum distributions, fluorescence quantum yields and degrees of fluorescence polarization vs. dye concentration were determined for indocyanine green in methanol, water and aqueous albumin solution. The monomer fluorescence quantum yield is limited to a few per cent by internal conversion. In water, dimerization starts at low concentrations (approximately 3 × 10 −8 m ol dm −3 ) and lowers the fluorescence quantum yield. The strong affinity of the dye to albumin shifts the onset of dimerization to higher concentrations. In methanol, dimerization is weak and closely spaced pair formation dominates at high concentrations. Dye adsorption to albumin and dye aggregation in the solvents were analysed experimentally and theoretically.
---
paper_title: Evaluation of stereoscopic medical video content on an autostereoscopic display for undergraduate medical education

paper_content:

Introduction: An increasing number of surgical procedures are performed in a microsurgical and minimally-invasive fashion. However, the performance of surgery, its possibilities and limitations become difficult to teach. Stereoscopic video has evolved from a complex production process and expensive hardware towards rapid editing of video streams with standard and HDTV resolution which can be displayed on portable equipment. This study evaluates the usefulness of stereoscopic video in teaching undergraduate medical students. ::: Material and methods: From an earlier study we chose two clips each of three different microsurgical operations (tympanoplasty type III of the ear, endonasal operation of the paranasal sinuses and laser chordectomy for carcinoma of the larynx). This material was added by 23 clips of a cochlear implantation, which was specifically edited for a portable computer with an autostereoscopic display (PC-RD1-3D, SHARP Corp., Japan). The recording and synchronization of left and right image was performed at the University Hospital Aachen. The footage was edited stereoscopically at the Waseda University by means of our original software for non-linear editing of stereoscopic 3-D movies. Then the material was converted into the streaming 3-D video format. The purpose of the conversion was to present the video clips by a file type that does not depend on a television signal such as PAL or NTSC. ::: 25 4th year medical students who participated in the general ENT course at Aachen University Hospital were asked to estimate depth clues within the six video clips plus cochlear implantation clips. Another 25 4th year students who were shown the material monoscopically on a conventional laptop served as control. ::: Results: All participants noted that the additional depth information helped with understanding the relation of anatomical structures, even though none had hands-on experience with Ear, Nose and Throat operations before or during the course. The monoscopic group generally estimated resection depth to much lesser values than in reality. Although this was the case with some participants in the stereoscopic group, too, the estimation of depth features reflected the enhanced depth impression provided by stereoscopy. ::: Conclusion: Following first implementation of stereoscopic video teaching, medical students who are inexperienced with ENT surgical procedures are able to reproduce depth information and therefore anatomically complex structures to a greater extent following stereoscopic video teaching. Besides extending video teaching to junior doctors, the next evaluation step will address its effect on the learning curve during the surgical training program.
---
paper_title: Microscope-integrated near-infrared indocyanine green videoangiography during surgery of intracranial aneurysms: the Helsinki experience.

paper_content:

BACKGROUND ::: Microscope-integrated near-infrared indocyanine green videoangiography (ICG-VA) is a new method of intraoperative blood flow assessment. The objective of this study was to evaluate the reliability of this technique in the evaluation of neck residuals and patency of branches after microneurosurgical clipping of intracranial aneurysms (IAs). ::: ::: ::: METHODS ::: During a period of 14 months, between November 2005 and December 2006, 289 patients with intracranial aneurysms were operated on in our institution. Intraoperative ICG-VA was performed during microneurosurgical clipping of 239 IAs in 190 patients. Postoperative computed tomography and computed tomography angiography (CTA) were performed for all patients. Intraoperative interpretation of ICG-VA in assessing the neck residual or the patency of vessels after clipping of each single aneurysm were recorded and correlated with postoperative CTA and/or digital subtraction angiography. ::: ::: ::: RESULTS ::: Postoperative imaging studies revealed no incomplete occlusions of aneurysm domes. Unexpected neck residuals were observed in 14 aneurysms (6%). There were no parent artery occlusions. Unexpected branch occlusions including both major and minor branching arteries were observed in 15 aneurysms (6%). ::: ::: ::: CONCLUSIONS ::: Indocyanine green videoangiograph is a simple and fast method of blood flow assessment with acceptable reliability. Indocyanine green videoangiograph can provide real-time information to assess blood flow in vessels of different size as well as the occlusion of the aneurysm. Intraoperative assessment of blood flow in the perforating branches is one of the most important advantages. In selected cases such as giant, complex, and deep-sited aneurysms or when the quality of image in ICG-VA is not adequate, other methods of intraoperative blood flow assessment should be considered.
---
paper_title: ASSESSMENT OF FLOW IN PERFORATING ARTERIES DURING INTRACRANIAL ANEURYSM SURGERY USING INTRAOPERATIVE NEAR‐INFRARED INDOCYANINE GREEN VIDEOANGIOGRAPHY

paper_content:

OBJECTIVE ::: Perforating arteries are commonly involved during the surgical dissection and clipping of intracranial aneurysms. Occlusion of perforating arteries is responsible for ischemic infarction and poor outcome. The goal of this study is to describe the usefulness of near-infrared indocyanine green videoangiography (ICGA) for the intraoperative assessment of blood flow in perforating arteries that are visible in the surgical field during clipping of intracranial aneurysms. In addition, we analyzed the incidence of perforating vessels involved during the aneurysm surgery and the incidence of ischemic infarct caused by compromised small arteries. ::: ::: ::: METHODS ::: Sixty patients with 64 aneurysms were surgically treated and prospectively included in this study. Intraoperative ICGA was performed using a surgical microscope (Carl Zeiss Co., Oberkochen, Germany) with integrated ICGA technology. The presence and involvement of perforating arteries were analyzed in the microsurgical field during surgical dissection and clip application. Assessment of vascular patency after clipping was also investigated. Only those small arteries that were not visible on preoperative digital subtraction angiography were considered for analysis. ::: ::: ::: RESULTS ::: The ICGA was able to visualize flow in all patients in whom perforating vessels were found in the microscope field. Among 36 patients whose perforating vessels were visible on ICGA, 11 (30%) presented a close relation between the aneurysm and perforating arteries. In one (9%) of these 11 patients, ICGA showed occlusion of a P1 perforating artery after clip application, which led to immediate correction of the clip confirmed by immediate reestablishment of flow visible with ICGA without clinical consequences. Four patients (6.7%) presented with postoperative perforating artery infarct, three of whom had perforating arteries that were not visible or distant from the aneurysm. ::: ::: ::: CONCLUSION ::: The involvement of perforating arteries during clip application for aneurysm occlusion is a usual finding. Intraoperative ICGA may provide visual information with regard to the patency of these small vessels.
---
paper_title: Intraoperative control of extracranial—intracranial bypass patency by near-infrared indocyanine green videoangiography

paper_content:

Object. Recently, intraoperative fluorescence angiography in which indocyanine green (ICG) is used as a tracer has been introduced as a novel technique to confirm successful aneurysm clipping. The aim of the present study was to assess whether ICG videoangiography is also suitable for intraoperative confirmation of extracranial‐intracranial bypass patency. Methods. Forty patients undergoing cerebral revascularization for hemodynamic cerebral ischemia (11 patients), moyamoya disease (18 patients), or complex intracranial aneurysms (11 patients) were included. Superficial temporal artery (STA)‐middle cerebral artery (MCA) bypass surgery was performed 35 times in 30 patients (five patients with moyamoya underwent bilateral procedures), STA‐posterior cerebral artery bypass surgery in two patients, and saphenous vein (SV) high-flow bypass surgery in eight patients. In each patient, following the completion of the anastomosis, ICG (0.3 mg/kg body weight) was given systemically via an intravenous bolus injection. A near-infrared light emitted by laser diodes was used to illuminate the operating field and the intravascular fluorescence was recorded using an optical filter‐equipped video camera. The findings of ICG videoangiography were compared with those of postoperative digital subtraction (DS) or computerized tomography (CT) angiography. In all cases excellent visualization of cerebral arteries, the bypass graft, and brain perfusion was noted. Indocyanine green videoangiography was used to identify four nonfunctioning STA‐MCA bypasses, which could be revised successfully in all cases. In two cases of SV high-flow bypasses, ICG videoangiography revealed stenosis at the proximal anastomotic site, which was also revised successfully. In all cases the final findings of ICG videoangiography could be positively validated during the postoperative course by performing DS or CT angiography. Conclusions. Indocyanine green videoangiography provides a reliable and rapid intraoperative assessment of bypass patency. Thus, ICG videoangiography may help reduce the incidence of early bypass graft failure.
---
paper_title: The impact of microscope-integrated intraoperative near-infrared indocyanine green videoangiography on surgery of arteriovenous malformations and dural arteriovenous fistulae.

paper_content:

BACKGROUND ::: Microscope-based intraoperative near-infrared indocyanine green (ICG) videoangiography is useful as an adjunct to intra- or postoperative digital subtraction angiography (DSA) in aneurysm surgery. ::: ::: ::: OBJECTIVE ::: To evaluate intraoperative ICG videoangiography for surgery of arteriovenous malformations (AVMs) and dural arteriovenous fistulas (dAVFs). ::: ::: ::: METHODS ::: Seventeen patients undergoing surgical resection of intracranial AVM or AVF were enrolled into this prospective evaluation. ICG videoangiography sequences were analyzed with regard to transit times to differentiate between arterial, early venous, capillary, and venous phase as well as early passage (fistula) and delayed appearance (ischemia). ICG videoangiography was compared with pre- and postoperative angiography. ::: ::: ::: RESULTS ::: Forty-six ICG videoangiographies were performed in 17 operative procedures. In 41 ICG investigations image quality and spatial resolution were excellent to analyze arterial, early venous, capillary, and venous phase. In 2 cases ICG videoangiography provided additional information to change the surgical strategy. With the exception of one case only, the postoperative angiogram corresponded to the last ICG examination performed after the resection. No side effects related to ICG injection were observed. In one patient with a deep thalamic AVM the final ICG investigation was inconclusive owing to insufficient illumination of the deep surgical field. ::: ::: ::: CONCLUSION ::: Microscope-integrated repetitive ICG videoangiography during AVM and dAVF surgery is fast, easy to perform, and safe. This simple and safe real-time method is a useful additional tool that can potentially lower the surgical risk in complex AVMs and help avoid missed residuals.
---
paper_title: Measurement of Cerebral Blood Flow in Newborn Infants Using Near Infrared Spectroscopy with Indocyanine Green

paper_content:

Cerebral blood flow (CBF) measurement by near infrared spectroscopy (NIRS) using oxyhemoglobin (Hbo2) as a tracer (CBF-Hbo2) needs rapid changes in arterial oxygen saturation (Sao2) which often cannot be achieved in many sick infants. An alternative method based on the same adaptation of the Fick principle using i.v. injection of the dye indocyanine green (ICG) is described (CBF-ICG). Six mechanically ventilated infants (age 26-38 wk, birth weight 0.885-3.730 kg) requiring supplementary oxygen therapy were studied within 72 h of birth. For CBF-ICG measurements, ICG (0.1 mg·kg-1 was injected via an umbilical venous catheter, and blood ICG concentration was measured by an optical umbilical artery catheter and brain ICG concentration was measured by NIRS. For CBF-HbO2 measurements the inspired oxygen concentration was rapidly increased, blood Hbo2 concentration was calculated from Sao2 measured by pulse oximetry, and brain Hbo2 concentration was measured by NIRS. A series of CBF measurements were performed using each method before and after altering the arterial carbon dioxide tension (Paco2). Mean CBF values from repeated measurements by each method at any given Paco2 were used to compare the methods. The SD of single measurements within an individual subject by CBF-ICG was 15%, and by CBF-HbO2, 24%. The relationship between the methods was mean CBF-ICG = (1.13. mean CBF-HbO2) - 2.76 mL·100 g-1·min-1 Hbo2 (r = 0.93, p< 0.001). The mean difference between the methods (CBF-ICG - CBF-Hbo2) was -0.25 mL·100 g-1·min-1 (95% confidence interval 6.30 to -6.80). The methods were in good agreement, and the use of i.v. ICG permitted rapid and repeated CBF measurements in the sickest infants at greatest risk of cerebral injury.
---
paper_title: PROSPECTIVE EVALUATION OF SURGICAL MICROSCOPE–INTEGRATED INTRAOPERATIVE NEAR-INFRARED INDOCYANINE GREEN ANGIOGRAPHY DURING CEREBRAL ARTERIOVENOUS MALFORMATION SURGERY

paper_content:

OBJECTIVE: Microscope-integrated indocyanine green (ICG) fluorescence angiography is a novel technique in vascular neurosurgery with potential utility in treating arteriovenous malformations (AVMs). METHODS: We analyzed the application of intraoperative ICG in 10 consecutive AVM surgeries for which surgical video was available. The ability to distinguish AVM vessels (draining veins, feeding and nidal arteries) from each other and from normal vessel was evaluated, and ICG angiographic findings were correlated with intra- and postoperative findings on digital subtraction angiography (DSA). RESULTS: ICG angiography was found to be useful by the surgeon in 9 of 10 patients. In 8 patients, it helped to distinguish AVM vessels. In 3 of 4 patients undergoing a postresection injection, it demonstrated that there was no residual arteriovenous shunting. In 1 patient, it helped to identify a small AVM nidus that was otherwise inapparent within a hematoma. Intraoperative DSA showed residual AVM in 2 of 10 patients requiring further resection of AVM not visualized during surgery. CONCLUSION: Microscope-integrated ICG angiography is a useful tool in AVM surgery. It can be used to distinguish AVM vessels from normal vessels and arteries from veins based on the timing of fluorescence with the dye. Our experience suggests that it is less useful with deep-seated lesions or when AVM vessels are not on the surface. ICG angiography complements rather than replaces DSA.
---
paper_title: Intraoperative indocyanine green angiography for obliteration of a spinal dural arteriovenous fistula.

paper_content:

Spinal dural arteriovenous fistulas (DAVFs) are the most common type of spinal arteriovenous malformation and are an important, underdiagnosed cause of progressive myelopathy and morbidity in patients with spine disorders. Successful microsurgical management of these lesions is dependent on the surgeon's ability to identify vessels of the fistula and to confirm its successful obliteration postintervention. Indocyanine green (ICG) fluorescent angiography is an emerging tool for delineating intraoperative vascular anatomy, and it has significant potential utility in the treatment of vascular disease in the spine. The authors present the case of a 76-year-old man with progressive and debilitating bilateral lower-extremity weakness and numbness on exertion, in whom a left T-8 spinal DAVF was diagnosed based on results of conventional spinal angiography. Unfavorable anatomy based on angiographic findings precluded endovascular embolization of the fistula, and the patient subsequently underwent T7-9 bilateral laminectomies for microsurgical clip occlusion. Intraoperative ICG fluorescent angiography was used before clip placement to identify the arterialized veins of the fistula, and after clip placement to confirm obliteration of the fistulous connection and restoration of normal blood flow. Intraoperative ICG angiography serves an important role in the microsurgical treatment of DAVF. It can be used to map the anatomy of the fistula in real time during surgery and to verify fistula obliteration rapidly after clip placement. This report adds to the growing body of literature demonstrating the importance of ICG angiography in vascular neurosurgery of the spine.
---
paper_title: Identification of the optimal cortical target point for extracranial–intracranial bypass surgery in patients with hemodynamic cerebrovascular insufficiency

paper_content:

OBJECT ::: The objective of this report is to describe a new approach to identify the optimal cortical target point for extracranial-intracranial (EC-IC) bypass surgery, to reliably find suitable recipient vessels for the anastomosis. ::: ::: ::: METHODS ::: Thirty consecutive patients (17 men and 13 women; mean age 54.6 +/- 11.79 years [+/- standard deviation]) with hemodynamic cerebrovascular insufficiency due to stenoocclusive arterial disease underwent EC-IC bypass surgery. The end of the Sylvian fissure was identified preoperatively using a specially designed template and external landmarks. At surgery, a 3-cm trephination was made, centered over the target point as determined by the template. The number, diameter, and length of the exposed cortical arteries were assessed using photographs and indocyanine green (ICG) angiograms. ::: ::: ::: RESULTS ::: At least 1 recipient artery appropriate for anastomosis (>or= 1 mm) was found in every craniectomy. The mean number of suitable recipient arteries per craniotomy was 2.09 +/- 0.87, the mean diameter was 1.28 +/- 0.24 mm, and the mean length 10.83 +/- 4.87 mm. Bypass patency was confirmed by intraoperative ICG angiography, postoperative computed tomography angiography, and digital subtraction angiography, and reached 100%. ::: ::: ::: CONCLUSIONS ::: Performing a 3-cm craniectomy over the described target point, reliably allows access to suitable recipient arteries for EC-IC bypass surgery.
---
paper_title: Near-infrared indocyanine green video angiography: a new method for intraoperative assessment of vascular flow.

paper_content:

OBJECTIVE ::: We report our initial clinical experience with a new method for intraoperative blood flow assessment. The purposes of the study were to assess the use of indocyanine green (ICG) video angiography in neurovascular cases, to assess the handling and image quality, to compare the findings with postoperative angiographic results, and to evaluate the clinical value of the method in a preliminary feasibility study. ::: ::: ::: METHODS ::: Fourteen patients with aneurysms (n = 12) or spinal (n = 1) or intracranial (n = 1) dural fistulae were included. Before and/or after aneurysm or dural fistula occlusion, ICG (25 mg) was injected intravenously. A near-infrared laser excitation light source (lambda = 780 nm) illuminated the operating field. The intravascular fluorescence of ICG (maximal lambda = 835 nm) was recorded by a nonintensified video camera, with optical filtering to block ambient and laser light for collection of only ICG-induced fluorescence. ::: ::: ::: RESULTS ::: A total of 21 investigations were performed for 14 patients. For the 17 successful ICG video angiographic investigations, image quality and resolution were excellent, allowing intraoperative real-time assessment of the cerebral circulation. ICG angiographic results could be divided into arterial, capillary, and venous phases, comparable to those observed with digital subtraction angiography. In all cases, the postoperative angiographic results corresponded to the intraoperative ICG video angiographic findings. In three cases, the information provided by intraoperative ICG angiography significantly changed the surgical procedure. ::: ::: ::: CONCLUSION ::: ICG video angiography is simple and provides real-time information on the patency of arterial and venous vessels of all relevant diameters, including small and perforating arteries (<0.5 mm), and the visible aneurysm sac. It may be a useful adjunct to improve the quality of neurovascular procedures and to document the intraoperative vascular flow.
---
paper_title: Preliminary personal experiences with the application of near-infrared indocyanine green videoangiography in extracranial vertebral artery surgery.

paper_content:

INTRODUCTION: We evaluated the feasibility, usefulness, and limitations of near-infrared indocyanine green (ICG) videoangiography during procedures involving the extracranial vertebral artery (VA). METHODS: Nine patients (2 women, 7 men; mean age, 55 years) were evaluated at 2 neurosurgical centers. Near-infrared ICG videoangiography was applied during transposition and rerouting of the first segment of VA (V1; n = 6) and during resection of neurinomas near the second (V2; n = 1 ) and third (V3; n = 2) segments of VA. RESULTS: Early after ICG injection, V1 fluoresced homogenously. The fluorescence of V2 and V3 varied. Without extrinsic compression, these segments appeared as noncontiguous hot spots because the VA runs freely in a periosteal sheath surrounded by a venous plexus that attenuates the fluorescent light. Hot spots corresponded to areas where the artery neared the surface. With extrinsic compression, VA enhanced homogenously because it was pushed against the periosteal layer. During the late phase, the V1 signal was attenuated, whereas the venous plexus surrounding V2 and V3 enhanced homogeneously, thereby masking the VA itself. Near-infrared ICG videoangiography helped to confirm VA patency during transposition and rerouting but was not helpful during VA exposure because the periosteal sheath must already be exposed to detect the VA or its surrounding plexus. After exposure, videoangiography can help to determine the position of the VA within its periosteal sheath. CONCLUSION:Videoangiography can be used to provide information about the patency of the VA and its location within the periosteal sheath to prevent injury during resection of tumor adherent to the periosteal sheath.
---
paper_title: Intraoperative indocyanine green angiography in intracranial aneurysm surgery: Microsurgical clipping and revascularization

paper_content:

BACKGROUND ::: The goal of this report is to illustrate the use of intraoperative indocyanine green (ICG) angiography in the surgical management of intracranial aneurysms, including microsurgical clipping and revascularization. ::: ::: ::: METHODS ::: This study included a series of 45 patients who were surgically treated between June 2007 and May 2008 for intracranial aneurysms. Fourty-three of the patients had anterior circulation aneurysms, and 2 had posterior circulation aneurysms. Forty-one patients were treated with microsurgical clipping. Four patients underwent revascularization combined with aneurysm dissection or trapping. Intraoperative ICG angiography was used to visualize the aneurysm clipping, patency of parent artery or graft. The ICG angiography technique is described, with particular reference to evaluation of the aneurysm clipping and revascularization. ::: ::: ::: RESULTS ::: Eighty-nine ICG angiography procedures were performed in 45 patients with intracranial aneurysms. The aneurysms were completely obliterated for all patients, and the grafts were patented for all except 1 patient. Pre-clipping ICG angiography showed the relationship of aneurysm and its parent artery clearly. After aneurysms being clipped, intraoperative ICG angiography found remnant of aneurysms, stenosis or occlusion of parent arteries and grafts in 8 cases, which were revised in the same surgical procedure. The results of ICG angiography correlated well with postoperative DSA in 97% patients. ::: ::: ::: CONCLUSION ::: ICG angiography can provide real-time information and guide revision in the same surgical procedure for the management of intracranial aneurysms.
---
paper_title: Prospective evaluation of surgical microscope—integrated intraoperative near-infrared indocyanine green videoangiography during aneurysm surgery

paper_content:

Object. The authors prospectively compared a new technique of surgical microscope-based indocyanine green (ICG) videoangiography with intraoperative or postoperative digital subtraction (DS) angiography. Method. The technique was performed during 187 surgical procedures in which 124 aneurysms in 114 patients were clipped. Using a newly developed setup, the ICG technique has been integrated into an operating microscope (Carl Zeiss Co., Oberkochen, Germany). A microscope-integrated light source containing infrared excitation light illuminates the operating field. The dye is injected intravenously into the patient, and intravascular fluorescence from within the blood vessels is imaged using a video camera attached to the microscope. The patency of parent, branching, and perforating arteries and documentation of clip occlusion of the aneurysm as shown by ICG videoangiography were compared with intraoperative or postoperative findings on DS angiography. The results of ICG videoangiography corresponded with int...
---
paper_title: Microscope-integrated quantitative analysis of intraoperative indocyanine green fluorescence angiography for blood flow assessment: first experience in 30 patients.

paper_content:

BACKGROUND ::: Intraoperative measurements of cerebral blood flow are of interest during vascular neurosurgery. Near-infrared indocyanine green (ICG) fluorescence angiography was introduced for visualizing vessel patency intraoperatively. However, quantitative information has not been available. ::: ::: ::: OBJECTIVE ::: To report our experience with a microscope with an integrated dynamic ICG fluorescence analysis system supplying semiquantitative information on blood flow. ::: ::: ::: METHODS ::: We recorded ICG fluorescence curves of cortex and cerebral vessels using software integrated into the surgical microscope (Flow 800 software; Zeiss Pentero) in 30 patients undergoing surgery for different pathologies. The following hemodynamic parameters were assessed: maximum intensity, rise time, time to peak, time to half-maximal fluorescence, cerebral blood flow index, and transit times from arteries to cortex. ::: ::: ::: RESULTS ::: For patients without obvious perfusion deficit, maximum fluorescence intensity was 177.7 arbitrary intensity units (AIs; 5-mg ICG bolus), mean rise time was 5.2 seconds (range, 2.9-8.2 seconds; SD, 1.3 seconds), mean time to peak was 9.4 seconds (range, 4.9-15.2 seconds; SD, 2.5 seconds), mean cerebral blood flow index was 38.6 AI/s (range, 13.5-180.6 AI/s; SD, 36.9 seconds), and mean transit time was 1.5 seconds (range, 360 milliseconds-3 seconds; SD, 0.73 seconds). For 3 patients with impaired cerebral perfusion, time to peak, rise time, and transit time between arteries and cortex were markedly prolonged (>20, >9 , and >5 seconds). In single patients, the degree of perfusion impairment could be quantified by the cerebral blood flow index ratios between normal and ischemic tissue. Transit times also reflected blood flow perturbations in arteriovenous fistulas. ::: ::: ::: CONCLUSION ::: Quantification of ICG-based fluorescence angiography appears to be useful for intraoperative monitoring of arterial patency and regional cerebral blood flow.
---
paper_title: Near-infrared indocyanine green videoangiography for assessment of carotid endarterectomy

paper_content:

Background ::: Intraoperative fluorescence angiography with indocyanine green (ICG) as a tracer has recently been introduced as a novel technique for neurosurgery. We evaluated the feasibility and efficacy of near-infrared (NIR) indocyanine green (ICG) videoangiography for patients undergoing carotid endarterectomy (CEA).
---
paper_title: Indocyanine green video-angiography as an aid to surgical treatment of spinal dural arteriovenous fistulae

paper_content:

Purpose ::: To illustrate the use of indocyanine green (ICG) video-angiography to confirm abolition of spinal dural arteriovenous fistula (SDAVF) and preserve the normal vascular anatomy intraoperatively.
---
paper_title: Intraoperative imaging techniques to assess coronary artery bypass graft patency.

paper_content:

Graft patency verification is increasingly recognized as an important component of coronary artery bypass grafting. Intuitively, eliminating intraoperative graft failure should reduce cardiac mortality and morbidity in the short term and improve clinical outcome in the long term. Although conventional angiography remains the gold standard technique for assessing graft patency, it is rarely available in the operating room and consequently several other less invasive approaches have been advocated. This article reviews the two currently most commonly used modalities for graft patency assessment, intraoperative fluorescence imaging and transit-time flowmetry, and discusses their value and limitations. Both techniques can reliably detect otherwise unsuspected occluded grafts and this is crucial for internal thoracic arteries because of their prognostic significance. Although neither technology can consistently identify more minor, non-occlusive abnormalities, the intraoperative fluorescence imaging technique seems to be more sensitive and less susceptible to "false positive" images.
---
paper_title: Preliminary experience with a novel intraoperative fluorescence imaging technique to evaluate the patency of bypass grafts in total arterial revascularization.

paper_content:

BACKGROUND ::: Early graft failure is a common cause of cardiac morbidity and mortality after coronary artery bypass grafting (CABG), and there is particular concern about graft patency in off-pump CABG. We describe our preliminary experience with a novel imaging technique (the SPY system), based on fluorescence of Indocyanine Green when exposed to near infrared light, for the intraoperative assessment of coronary graft patency. ::: ::: ::: METHODS ::: Graft patency was assessed in patients undergoing off-pump and on-pump total arterial revascularization. The imaging technique requires injection of a 1-mL bolus of Indocyanine Green into the central venous line, followed by imaging with the SPY system. ::: ::: ::: RESULTS ::: We assessed intraoperative graft patency in 213 conduits in 84 patients (mean, 2.54 grafts per patient), of which, 65 (77%) were done off-pump. It took approximately 3 minutes to image each graft. Skeletonized conduits provided better visualization than pedicled ones. Fluorescence, confirming graft patency, was observed in all but four (1.9%) conduits in 4 (5%) patients. In these latter cases, graft revision was necessitated. ::: ::: ::: CONCLUSIONS ::: Fluorescence imaging of coronary grafts using the SPY is a uniquely simple, safe, noninvasive, and reproducible technique for intraoperative confirmation of graft patency. In 4 patients, it necessitated revision of the initial intraoperative procedure. Quantification of graft flow would enhance the value of the system.
---
paper_title: The Graft Imaging to Improve Patency (GRIIP) clinical trial results.

paper_content:

OBJECTIVE ::: This trial aimed to determine whether intraoperative graft assessment with criteria for graft revision would decrease the proportion of patients with 1 or more graft occlusions or stenoses or major adverse cardiac events 1 year after coronary artery bypass grafting. ::: ::: ::: METHODS ::: A single-center, randomized, single-blinded, controlled clinical trial was designed. Patients were randomized to either of 2 groups: intraoperative graft patency assessment using indocyanine-green fluorescent angiography and transit-time flowmetry, with graft revision according to a priori criteria (imaging group), or standard intraoperative management (control group). Patients underwent follow-up angiography at 1 year. ::: ::: ::: RESULTS ::: Between September 2005 and August 2008, 156 patients undergoing isolated coronary bypass grafting were enrolled (imaging, n = 78; control, n = 78). Demographic and angiographic characteristics were similar between groups. Operative, crossclamp, and cardiopulmonary bypass times were all nonsignificantly longer in the imaging arm. The number of grafts per patients was similar (imaging, 3.0 +/- 0.7; control, 3.0 +/- 0.7). The frequency of major adverse cardiac events (death, myocardial infarction, repeat revascularization) was not different between groups at 1 year postoperatively (imaging, 7.7%; control, 7.7%). One-year angiography was performed in 107 patients (imaging, 55 patients/160 grafts; control, 52 patients/152 grafts). The proportion of patients with 1 graft occlusion or more was comparable in the imaging (30.9%) and control (28.9%) groups (relative risk [95% confidence interval], 1.1 [0.6-1.9]; P = .82), as were other graft patency end points. The incidence of saphenous vein graft occlusion was high in both groups. ::: ::: ::: CONCLUSIONS ::: Routine intraoperative graft assessment is safe but does not lead to a marked reduction in graft occlusion 1-year after bypass grafting. The incidence of saphenous vein graft failure remains high despite contemporary practice and routine intraoperative graft surveillance.
---
paper_title: Near-Infrared Fluorescence Coronary Angiography: A New Noninvasive Technology for Intraoperative Graft Patency Control

paper_content:

resulted in an impairment of the myocardial perfusion visualized by FCA. Occlusion of the LAD or the diagonal branch resulted in a total perfusion defect of the corresponding anterior myocardial wall with immediate reperfusion after releasing the snare. In 5 cases a patent bypass graft with an apparent homogenous perfusion of the corresponding myocardium was detectable. In one procedure, FCA images indicated total occlusion of the bypass graft and a total perfusion deficit in the distal LAD region. Correlation between FCA and coronary angiography in detection of stenoses and graft patency was excellent. Conclusion: With the fluorescence technique using ICG, visualization of blood flow in coronary vessels and bypass grafts, as well as of myocardial perfusion, is feasible. FCA is a highly sensitive and reproducible method and an excellent technique for intraoperative quality control in CABG.
---
paper_title: Improving the quality of coronary bypass surgery with intraoperative angiography: validation of a new technique.

paper_content:

OBJECTIVES ::: We report a comprehensive assessment and validation of a new intraoperative angiography technique. ::: ::: ::: BACKGROUND ::: Technical problems at the site of the distal anastomosis compromise an underappreciated proportion of coronary bypass grafts. The absence of a systematic, validated technique to verify graft patency in the operating room represents a significant breach in quality assurance. ::: ::: ::: METHODS ::: Fluorescent indocyanine green (ICG) dye is excited with dispersed laser light to create an angiographic depiction of the graft, native vessel, and anastomosis. One-hundred twenty patients underwent ICG angiography. Angiograms were reviewed for reliability and validity studies. ::: ::: ::: RESULTS ::: A total of 348 coronary bypass grafts were studied. Each ICG angiogram took 2.2 +/- 1.1 min to perform. The ICG angiography found 4.2% of patients had significant graft problems requiring major revision. Quality of visualization was rated according to a seven-point Likert scale (1 = worst, 7 = best). Among conduits, saphenous veins were best visualized (mean score +/- standard deviation), 6.4 +/- 1.5 versus 5.5 +/- 1.9 for internal mammary arteries and 4.4 +/- 2.3 for radial arteries (p = 0.02). Location of distal anastomosis did not influence quality of visualization. There was high inter-rater reliability for graft revision (kappa = 1.0) and graft patency (kappa = 0.97) between surgeons. Sensitivity and specificity of the ICG angiograms for graft stenosis >50% was 100% among 22 grafts also studied with X-ray angiography. ::: ::: ::: CONCLUSIONS ::: Information from ICG angiograms led to graft revisions for technical problems in 4.2% of patients that would have otherwise gone unrecognized. Intraoperative angiography is an emerging tool for improving the quality of coronary bypass surgery.
---
paper_title: Fluorescent Cardiac Imaging: A Novel Intraoperative Method for Quantitative Assessment of Myocardial Perfusion During Graded Coronary Artery Stenosis

paper_content:

Background-The purpose of the present study was to examine whether the effect of coronary stenoses of variable severity on myocardial perfusion can be quantitatively assessed in vivo by analysis of fluorescent cardiac imaging (FCI) compared with the gold standard, the fluorescent microsphere method. FCI is a novel technology to visualize coronary vessels and myocardial perfusion intraoperatively using the indocyanine green dye with an infrared-sensitive imaging device. Methods and Results-Graded stenoses and total vessel occlusion of the left anterior descending coronary artery were created in 11 open-chest pigs. Stenoses were graded to reduce resting left anterior descending coronary artery flow by 25%, 50%, 75%, and 100% of baseline flow measured by transit-time flowmeter. FCI images were analyzed with a digital image processing system. The impairment of myocardial perfusion was quantified by background-subtracted peak fluorescence intensity and slope of fluorescence intensity obtained with FCI and compared with myocardial blood flow assessed by fluorescent microsphere. All stenoses resulted in an impairment of myocardial perfusion visualized by FCI. Occlusion of the left anterior descending coronary artery resulted in a total perfusion defect (no fluorescence intensity) of the corresponding anterior myocardial wall. During graded stenosis and total vessel occlusion, normalized background-subtracted peak fluorescence intensity and slope of fluorescence intensity decreased significantly (P<0.0001). Both background-subtracted peak fluorescence intensity (r=0.92, P<0.0001) and slope of fluorescence intensity (r=0.93, P<0.0001) analyzed by FCI demonstrated good linear correlation with fluorescent microsphere-derived myocardial blood flow. Conclusions-The impairment of myocardial perfusion in response to increased coronary stenosis severity and total vessel occlusion can be quantitatively assessed by FCI and correlates well with results obtained by fluorescent microsphere.
---
paper_title: Graft revision after transit time flow measurement in off-pump coronary artery bypass grafting

paper_content:

Objective: To determine whether coronary graft patency can be predicted by transit time flow measurement (TTFM). Methods: From May 1 1997 to December 31 1998, TTFM was prospectively evaluated in 409 patients undergoing coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB). All grafts (1145) were tested with TTFM. Results: Thirty-seven out of 1145 grafts (3.2%) were revised in 33 patients (7.6%). In six cases (18.1%) use of CPB was necessary during revision due to hemodynamic instability. The remaining patients underwent revision off-pump. Thirty-four grafts (91.9%) were revised for both low flow and abnormal flow curve patterns. Findings at revision included: thrombosis of the anastomosis (na 6), stenosis at the toe or heel of the anastomosis (na 8), coronary flap or dissection (na 5), dissection of the internal mammary artery (na 5), graft kinking (na 4), flap at proximal anastomosis (na 1), coronary stenosis distal to the graft (na 3), and no findings (na 2). After revision all flow values and flow patterns improved. Although three additional grafts (8.1%) were revised for low flow (,7 ml/min) despite normal flow patterns, there were no findings at revision and flow values and curves remained unchanged after revision. Postoperatively, one patient developed a stroke (3%), one had an acute myocardial infarction (MI) (3%), one had a sternal wound infection (3%), and one required prolonged ventilatory support (3%). Conclusion: Evaluation of TTFM is valuable in determining the status of a coronary graft after CABG. Correct interpretation of flow patterns allows for correction of abnormalities prior to chest closure. q 2000 Elsevier Science B.V. All rights reserved.
---
paper_title: SPY: an innovative intra-operative imaging system to evaluate graft patency during off-pump coronary artery bypass grafting.

paper_content:

Off-pump coronary artery bypass grafting (CABG) has been rapidly increased, because of its less invasiveness with low complications. However, graft patency rate highly depends on the operators' capability due to technical difficulties. The SPY system, based on the fluorescence of indocyanine green, is an innovative device that permits validation of graft patency intra-operatively. Real time images of grafts are obtained with no need for catheterization, X-rays or iodine contrast medium. High-quality images could be obtained in all 290 grafts of 72 off-pump CABG cases (mean 4.0 grafts per patient). Four anastomoses (1.4%), including two proximal and two distal, were revised because of defects detected by SPY images. In one case, the SPY system revealed no blood flow in a radial sequential graft, although transit-time flow meter measurements showed a diastolic dominant pattern. SPY images provide critical information to surgeons to detect non-patent grafts, allowing them to be revised while the patient is still on the operating table. Using the SPY system, technical failures could be completely resolved during surgery. The use of the SPY system for intra-operative graft validation during off-pump CABG may become the gold standard for surgical management in the near future.
---
paper_title: Novadaq SPY: intraoperative quality assessment in off-pump coronary artery bypass grafting.

paper_content:

OBJECTIVES ::: Off-pump coronary artery bypass grafting may decrease operative morbidity when compared to on-pump bypass grafting; however, it is technically demanding and thus quality control is essential. This study assesses the clinical feasibility of a new, indocyanine green (ICG)-based imaging system (SPY; Novadaq Technologies; Toronto, ON, Canada) to monitor the quality of anastomoses and grafts in off-pump revascularization. ::: ::: ::: SETTING ::: Thirty-eight consecutive patients undergoing nonemergent coronary artery bypass grafting without the use of extracorporeal circulation at two Swiss cardiac surgery clinics were included. On completion of bypass grafts, the quality of the grafts was assessed using the ICG-based imaging system. The imaging device comprises an 806-nm laser light source that is used to cause ICG to fluoresce and a near infrared-sensitive charged couple device videocamera that is used to capture the fluorescence images. ICG was administered through the central venous line, and images were acquired during the first pass of the ICG through the field of view. Graft flow (qualitative) and the quality of the grafts and anastomoses were assessed intraoperatively. ::: ::: ::: RESULTS ::: Between March 2002 and September 2002, a total of 38 patients (26 men and 12 women; mean +/- SD age, 64.6 +/- 10.5 years; body mass index, 27.1 +/- 2.9) underwent surgery and imaging at two institutions. One hundred seven of 124 grafts (45 arteries and 62 veins) were analyzed. Seventeen grafts could not be assessed due to difficulties in positioning. The imaging system was easy to handle, and no adverse reactions to ICG were observed. Four of the 107 grafts imaged required revision (three anastomotic constrictions and one graft dissection). Each imaging sequence required approximately 1.25 to 2.5 mg of ICG. The images were equivalent to angiography without the need for radiographs and catheter insertion. In addition, the course of coronaries that would otherwise be difficult to locate in obese patients could be detected using the imaging system. Biochemical and ECG data demonstrated an absence of intraoperative or postoperative myocardial damage, and no liver enzyme elevation or renal dysfunction. ::: ::: ::: CONCLUSIONS ::: This study supports the clinical utility of a ICG-based imaging system for the assessment of the quality of bypass grafts, which appears to be safe and simple to use.
---
paper_title: A new and simplified method for coronary and graft imaging during CABG.

paper_content:

BACKGROUND ::: Improvements in percutaneous catheter interventions and new technical demands in the practice of coronary surgery have increased the need for an accurate and easy-to-use imaging modality for validating the quality of bypass grafts in the operating room. This report examines the initial clinical use of fluorescent cardiac imaging, a technology that uses indocyanine green (ICG) with a portable imaging device to visualize coronary anatomy and grafts intraoperatively. ::: ::: ::: METHODS ::: The modality was evaluated at two institutions in 20 patients undergoing non-emergent CABG or MIDCAB with respect to safety, feasibility of use, and image quality. Images were generated and acquired with a portable laser diode/infrared camera device after injection of 0.5 ml of ICG (0.5-5.0 mg/ml) either intravenously, via the antegrade cardioplegia cannula, or via the cardiopulmonary bypass circuit. ::: ::: ::: RESULTS ::: There were no ICG- or imaging device-related complications. The technology was easy-to-use during conventional CABG as well as MIDCAB and adequately demonstrated coronary anatomy, filling of the grafts, and graft patency in all but two patients. In one patient, the use of the modality resulted in the intraoperative recognition and revision of a non-functioning graft. ::: ::: ::: CONCLUSION ::: This technology is user-friendly in the operating room, appears to be safe, provides good-quality images of coronary anatomy and grafts, and holds promise as an intraoperative graft validation tool for conventional and minimally invasive CABG.
---
paper_title: Application of novel dynamic optical imaging for evaluation of peripheral tissue perfusion.

paper_content:

Measurement of functional tissue perfusion should be needed for preventive measures, early diagnosis, and adequate treatment especially in the patients with peripheral vascular diseases (PVD). Significant attention has also been given to in vivo near-infrared (NIR) fluorescence imaging because of deep tissue penetration due to low absorbance and scattering. In this study, a new method, indocyanine green (ICG) perfusion imaging to evaluate the peripheral tissue perfusion that employs the intravenous injection of ICG dye, planar imaging with a CCD digital imaging system, and analysis of spatiotemporal dynamics have been applied to diagnose perfusion rate of human lower extremities from a normal and a PVD case. The feet tissue perfusions of the PVD patient were measured as 25% to 50% compared with those of normal feet tissue. The diagnostic result indicates that ICG perfusion imaging method is sensitive enough to diagnose PVD and take noninvasive monitoring treatment effects of peripheral vascular diseases in clinical setting.
---
paper_title: Preliminary experience with a novel fluorescence lymphography using indocyanine green in patients with secondary lymphedema

paper_content:

Background Lymphoscintigraphy has largely been performed to diagnose lymphedema. It is, however a time-consuming and expensive technique, which has not been covered by Japanese medical insurance since the year 2002. In this report we introduce a new imaging technique of fluorescent lymphography to diagnose lymphedema. Methods Fluorescence images of subcutaneous lymphatic drainage after subcutaneous injection of indocyanine green (ICG) at the foot were obtained using a newly developed near-infrared camera system. ICG fluorescent lymphography was performed in 12 patients with secondary lymphedema and 10 healthy volunteers. The 12 patients were diagnosed with secondary lymphedema according to the medical history and lymphoscintigram, of which 11 had a history of hysterectomy with extended lymph node dissection and local radiation therapy for uterine cancer. Lymphedema developed in one patient after femorotibial artery bypass for peripheral artery occlusive disease. Results Four abnormal fluorescent patterns of the lymph drainage were observed in lymphedema: dermal backflow (an abnormal filling of the lymph capillaries), extended fluorescent signal at the dorsum and plantar region of the foot, dilated lymph channels with proximal obliteration, and diffuse glittering of fluorescent signals with scattered twinkling of the dye. Continuous lymph channels from the injection site of the foot to the groin were observed along the medial aspect of thigh in healthy subjects. Conclusion ICG fluorescence lymphography is safe, simple, and minimally invasive. The device is portable and easy to use. The technique may be useful in clinical practice to identify presence of lymphatic disorder.
---
paper_title: Quantitative Analysis of Peripheral Tissue Perfusion Using Spatiotemporal Molecular Dynamics

paper_content:

BACKGROUND ::: Accurate measurement of peripheral tissue perfusion is challenging but necessary to diagnose peripheral vascular insufficiency. Because near infrared (NIR) radiation can penetrate relatively deep into tissue, significant attention has been given to intravital NIR fluorescence imaging. ::: ::: ::: METHODOLOGY/PRINCIPAL FINDINGS ::: We developed a new optical imaging-based strategy for quantitative measurement of peripheral tissue perfusion by time-series analysis of local pharmacokinetics of the NIR fluorophore, indocyanine green (ICG). Time-series NIR fluorescence images were obtained after injecting ICG intravenously in a murine hindlimb ischemia model. Mathematical modeling and computational simulations were used for translating time-series ICG images into quantitative pixel perfusion rates and a perfusion map. We could successfully predict the prognosis of ischemic hindlimbs based on the perfusion profiles obtained immediately after surgery, which were dependent on the preexisting collaterals. This method also reflected increases in perfusion and improvements in prognosis of ischemic hindlimbs induced by treatment with vascular endothelial growth factor and COMP-angiopoietin-1. ::: ::: ::: CONCLUSIONS/SIGNIFICANCE ::: We propose that this novel NIR-imaging-based strategy is a powerful tool for biomedical studies related to the evaluation of therapeutic interventions directed at stimulating angiogenesis.
---
paper_title: Dynamic fluorescence imaging of indocyanine green for reliable and sensitive diagnosis of peripheral vascular insufficiency.

paper_content:

Quantitative measurement of functional tissue perfusion is essential for early diagnosis and proper treatment of peripheral arterial occlusive disease (PAOD). We have previously demonstrated that dynamic imaging of near-infrared fluorophore indocyanine green (ICG) can be a noninvasive and sensitive tool to measure tissue perfusion. In the present study, we investigated the clinical efficacy of ICG perfusion imaging method for the diagnosis of PAOD. Total nineteen PAOD patients and age-matched controls (n=10) were evaluated for lower extremity tissue perfusion using ICG perfusion imaging. The perfusion rates of the lower extremities with severe PAOD (n=25 legs, 16.6±8.3%/min) were significantly lower than those of normal controls (38.1±17.3%/min, p<0.001). In cases of mild PAOD, the perfusion rates (n=11 legs, 18.3±10.3%/min) were also significantly lower compared to the control; while the conventional ankle-brachial index (ABI) test failed to detect mild functional impairment. These results collectively indicate that ICG perfusion imaging can be a very effective tool for diagnosis of PAOD with a superior efficacy in comparison to conventional ABI test.
---
paper_title: Visualized Sclerotherapy of Varicose Veins

paper_content:

BACKGROUND The spread and movement of sclerosant after injection during sclerotherapy is difficult to monitor. ::: ::: ::: ::: OBJECTIVE To develop a new visualization method that allows monitoring of sclerosant dosage and flow during sclerotherapy. ::: ::: ::: ::: METHODS We used a photodynamic eye (PDE) to perform indocyanine green (ICG) imaging. ICG produces strong fluorescence detectable using PDE and allows monitoring of sclerosant spread through blood vessels in real time. We performed visualized sclerotherapy on 50 limbs, comprising high ligation and sclerotherapy (35 limbs), stripping and sclerotherapy (10 limbs), and sclerotherapy alone (5 limbs). ::: ::: ::: ::: RESULTS In all cases, fluorescence imaging of the injected sclerosant was possible. No complications resulted from combining ICG and polidocanol in any of the patients, all of whom received follow-up evaluations at 1 week, 1 month, and 3 months after treatment. ::: ::: ::: ::: CONCLUSIONS Our new method not only avoids the risk of radiation exposure, but also allows for simple observation of sclerosant range of access, determination of the dosage for each lesion, and accurate administration of therapy to target lesions. This method will contribute to further advances in sclerotherapy, given that it allows administration of sclerosant and visual confirmation of optimal injection dosage, speed, and movement of sclerosant after injection. ::: ::: ::: ::: The authors have indicated no significant interest with commercial supporters.
---
paper_title: Effects of levosimendan on indocyanine green plasma disappearance rate and the gastric mucosal-arterial pCO2 gradient in abdominal aortic aneurysm surgery.

paper_content:

Background: Levosimendan has a dual mechanism of action: it improves myocardial contractility and causes vasodilatation without increasing myocardial oxygen demand. In a laboratory setting, it selectively increases gastric mucosal oxygenation in particular and splanchnic perfusion in general. The aim of our study was to describe the effects of levosimendan on systemic and splanchnic circulation during and after abdominal aortic surgery. ::: ::: ::: ::: Methods: Twenty abdominal aortic aneurysm surgery patients were randomized to receive either levosimendan (n=10) or placebo (n=10) in a double-blinded manner. Both the mode of anaesthesia and the surgical procedures were performed according to the local guidelines. Automatic gas tonometry was used to measure the gastric mucosal partial pressure of carbon dioxide. Systemic indocyanine green clearance plasma disappearance rate (ICG-PDR) was used to estimate the total splanchnic blood flow. ::: ::: ::: ::: Results: The immediate post-operative recovery was uneventful in the two groups with a comparable, overnight length of stay in the intensive care unit. Cumulative doses of additional vasoactive drugs were comparable between the groups, with a tendency towards a higher cumulative dose of noradrenaline in the levosimendan group. After aortic clamping, the cardiac index was higher [4(3.8–4.7) l/min/m2 vs. 2.6(2.3–3.6) l/min/m2; P<0.05] and the gastric mucosal–arterial pCO2 gradient was lower in levosimendan-treated patients [0.9(0.6–1.2) kPa vs. 1.7(1.2–2.1) kPa; (P<0.05)]. However, the total splanchnic blood flow, estimated by ICG-PDR, was comparable [29(21–29)% vs. 20(19–25)%; NS]. Organ dysfunction scores (sequential organ dysfunction assessment) were similar between the groups on the fifth post-operative day. ::: ::: ::: ::: Conclusion: Levosimendan favours gastric perfusion but appears not to have a major effect on total splanchnic perfusion in patients undergoing an elective aortic aneurysm operation.
---
paper_title: Segmental analysis of indocyanine green pharmacokinetics for the reliable diagnosis of functional vascular insufficiency

paper_content:

Accurate and reliable diagnosis of functional insufficiency of peripheral vasculature is essential since Raynaud phenomenon (RP), most common form of peripheral vascular insufficiency, is commonly associated with systemic vascular disorders. We have previously demonstrated that dynamic imaging of near-infrared fluorophore indocyanine green (ICG) can be a noninvasive and sensitive tool to measure tissue perfusion. In the present study, we demonstrated that combined analysis of multiple parameters, especially onset time and modified T max which means the time from onset of ICG fluorescence to T max , can be used as a reliable diagnostic tool for RP. To validate the method, we performed the conventional thermographic analysis combined with cold challenge and rewarming along with ICG dynamic imaging and segmental analysis. A case-control analysis demonstrated that segmental pattern of ICG dynamics in both hands was significantly different between normal and RP case, suggesting the possibility of clinical application of this novel method for the convenient and reliable diagnosis of RP.
---
paper_title: Indocyanine green enables near-infrared fluorescence imaging of lipid-rich, inflamed atherosclerotic plaques.

paper_content:

New high-resolution molecular and structural imaging strategies are needed to visualize high-risk plaques that are likely to cause acute myocardial infarction, because current diagnostic methods do not reliably identify at-risk subjects. Although molecular imaging agents are available for low-resolution detection of atherosclerosis in large arteries, a lack of imaging agents coupled to high-resolution modalities has limited molecular imaging of atherosclerosis in the smaller coronary arteries. Here, we have demonstrated that indocyanine green (ICG), a Food and Drug Administration-approved near-infrared fluorescence (NIRF)-emitting compound, targets atheromas within 20 min of injection and provides sufficient signal enhancement for in vivo detection of lipid-rich, inflamed, coronary-sized plaques in atherosclerotic rabbits. In vivo NIRF sensing was achieved with an intravascular wire in the aorta, a vessel of comparable caliber to human coronary arteries. Ex vivo fluorescence reflectance imaging showed high plaque target-to-background ratios in atheroma-bearing rabbits injected with ICG compared to atheroma-bearing rabbits injected with saline. In vitro studies using human macrophages established that ICG preferentially targets lipid-loaded macrophages. In an early clinical study of human atheroma specimens from four patients, we found that ICG colocalized with plaque macrophages and lipids. The atheroma-targeting capability of ICG has the potential to accelerate the clinical development of NIRF molecular imaging of high-risk plaques in humans.
---
paper_title: Indocyanine green angiography: A new method to quantify collateral flow in mice

paper_content:

OBJECTIVES ::: Therapeutic augmentation of collateral artery growth (ie, arteriogenesis) is of particular clinical interest for improving blood flow in vascular occlusive disease. Quantification of collateralization in small animal models is difficult, however, and the commonly used technique of laser Doppler perfusion imaging (LDPI) has always been criticized. Therefore, a new method, termed indocyanine green angiography (ICGA), was established for in vivo imaging of arteriogenesis in mice and compared with LDPI. ::: ::: ::: METHOD ::: Using the accepted model of ligation of the left femoral artery of 45 C57BL6 mice, we determined arteriogenesis both by LDPI and ICGA, which were applied before and periodically after ligation of the left femoral artery (each group n = 7). Collateral artery growth within the hind limb was additionally verified by histologic workup. ::: ::: ::: RESULTS ::: Determination of flow by ICGA, as represented by maximal pixel intensity (ratio of left/right hind limb) demonstrated a drop from 0.97 +/- 0.06 before ligation to 0.11 +/- 0.12 directly after ligation, which recovered to 0.48 +/- 0.22 after 1 week, to 0.65 +/- 0.11 after 2 weeks, and to 0.59 +/- 0.22 after 3 weeks (n = 7, P < .05). Similarly, flow determined as the perfusion index (slope of pixel intensity, ratio left/right) dropped from 1.18 +/- 0.4 before ligation to 0.02 +/- 0.03 immediately after ligation but recovered to 0.08 +/- 0.01 after 1 week, to 0.17 +/- 0.01 after 2 weeks, and to 0.17 +/- 0.06 after 3 weeks (n = 7, P < .05). Quantification by LDPI demonstrated a drop from 1.06 +/- 0.06 (left/right ratio) before ligation to 0.37 +/- 0.03 immediately after ligation. In contrast to ICGA, perfusion recuperated completely within 1 week to 1.01 +/- 0.14 and tended to be even higher in the ligated than in the unligated hind limb after 2 (1.09 +/- 0.25) and 3 weeks (1.20 +/- 0.29), pointing towards limitations of this technique. Histologic analysis confirmed the significant increase in the number of collaterals. The intraindividual ratio increased from 1.0 +/- 0.05 before ligation to 1.35 +/- 0.10 at 2 weeks and 1.41 +/- 0.08 at 3 weeks after ligation (P < .05). ::: ::: ::: CONCLUSION ::: Our data demonstrate that ICGA represents a potent tool for the quantification of collateral flow in small animal models. The current standard of LDPI seems to rather represent blood movements within the superficial skin but not of the entire hind limb.
---
paper_title: Early Postoperative Detection of Tissue Necrosis in Amputation Stumps With Indocyanine Green Fluorescence Angiography

paper_content:

OBJECTIVE: Amputations of the lower extremity due to irreversible ischemic tissue loss are performed as distally as possible. Therefore, oftentimes wound-healing disorders develop, requiring additional surgical treatment. METHODS: The amputations stumps of 10 patients with irreversible ischemic tissue loss due to arteriosclerosis were investigated within 72 hours postoperatively with indocyanine green (ICG) fluorescence. RESULTS: For 6 of the investigated stumps, no perfusion deficit could be seen through fluorescence angiography. All stumps displayed primary healing. In the fluorescence angiography of 3 amputations, stump perfusions deficits predicted later tissue necrosis and had to be amputated again in a second operation. One amputation wound showed a small ICG perfusion deficit that represented a blood clot. CONCLUSION: Indocyanine green fluorescence angiography allows a perfusion analysis of amputation stumps and therefore a prediction of the expected tissue necrosis. This tool may allow reliable prediction of amputation level.
---
paper_title: Sentinel Node Biopsy by Indocyanine Green Retention Fluorescence Detection for Inguinal Lymph Node Staging of Anal Cancer: Preliminary Experience

paper_content:

Background ::: There is some evidence that sentinel lymph node (SLN) biopsy guided by dye injection and/or radioisotopes can improve staging of inguinal lymph nodes (LNs) in anal cancer. This study was performed to investigate the feasibility of fluorescence detection of SLN and lymphatic mapping in anal cancer.
---
paper_title: Sentinel Lymph Nodes and Lymphatic Vessels: Noninvasive Dual-Modality in Vivo Mapping by Using Indocyanine Green in Rats—Volumetric Spectroscopic Photoacoustic Imaging and Planar Fluorescence Imaging

paper_content:

PURPOSE ::: To noninvasively map sentinel lymph nodes (SLNs) and lymphatic vessels in rats in vivo by using dual-modality nonionizing imaging-volumetric spectroscopic photoacoustic imaging, which measures optical absorption, and planar fluorescence imaging, which measures fluorescent emission-of indocyanine green (ICG). ::: ::: ::: MATERIALS AND METHODS ::: Institutional animal care and use committee approval was obtained. Healthy Sprague-Dawley rats weighing 250-420 g (age range, 60-120 days) were imaged by using volumetric photoacoustic imaging (n = 5) and planar fluorescence imaging (n = 3) before and after injection of 1 mmol/L ICG. Student paired t tests based on a logarithmic scale were performed to evaluate the change in photoacoustic signal enhancement of SLNs and lymphatic vessels before and after ICG injection. The spatial resolutions of both imaging systems were compared at various imaging depths (2-8 mm) by layering additional biologic tissues on top of the rats in vivo. Spectroscopic photoacoustic imaging was applied to identify ICG-dyed SLNs. ::: ::: ::: RESULTS ::: In all five rats examined with photoacoustic imaging, SLNs were clearly visible, with a mean signal enhancement of 5.9 arbitrary units (AU) + or - 1.8 (standard error of the mean) (P < .002) at 0.2 hour after injection, while lymphatic vessels were seen in four of the five rats, with a signal enhancement of 4.3 AU + or - 0.6 (P = .001). In all three rats examined with fluorescence imaging, SLNs and lymphatic vessels were seen. The average full width at half maximum (FWHM) of the SLNs in the photoacoustic images at three imaging depths (2, 6, and 8 mm) was 2.0 mm + or - 0.2 (standard deviation), comparable to the size of a dissected lymph node as measured with a caliper. However, the FWHM of the SLNs in fluorescence images widened from 8 to 22 mm as the imaging depth increased, owing to strong light scattering. SLNs were identified spectroscopically in photoacoustic images. ::: ::: ::: CONCLUSION ::: These two modalities, when used together with ICG, have the potential to help map SLNs in axillary staging and to help evaluate tumor metastasis in patients with breast cancer.
---
paper_title: Photothermal effects on murine mammary tumors using indocyanine green and an 808-nm diode laser: an in vivo efficacy study.

paper_content:

Murine mammary tumors were treated using indocyanine green and an 808 nm diode laser, and the in vivo chromophore-enhanced photothermal effects on the tumor burden and on tumor rat survival were investigated. The power of the laser was selected in the range of 5-10 W, and irradiation duration 3-5 min. One percent aqueous indocyanine green solution in a volume of 100-200 microliters was administered in situ, either acutely or 24 h prior to the treatment. The photothermal interaction was apparent under all our treatment conditions with a well-defined spatial containment in this study and the tumor growth was slowed after treatment. The post-treatment observation showed tumor recurrence and metastasis; no long-term survival was achieved with the single application of laser in conjunction with indocyanine green. Our results pose a question on the efficacy of the photothermal interaction even though tumor cell destruction can be achieved in a large and controlled scale. However, this highly selective photothermal impact on the tumor tissue did suggest that this method be applied repeatedly to be more effective and be used as the precursor of other modalities, such as chemotherapy, radiation therapy, immunotherapy, and surgery.
---
paper_title: Identification of lymphatic pathway involved in the spreading of prostate cancer by fluorescence navigation approach with intraoperatively injected indocyanine green.

paper_content:

OBJECTIVE ::: : The objective of this study was to identify lymphatic vessels draining from the prostate by using a fluorescence navigation (FN) system. ::: ::: ::: METHODS ::: : Fourteen subjects were candidates for radical retropubic prostatectomy (RRP) and pelvic lymph node dissection (PLND). After an indocyanine green solution was injected into the prostate during RRP, lymphatic vessels draining from the prostate were analyzed using a FN system. After PLND based on lymphatic mapping by the FN system (in vivo probing) was performed in the external iliac, obturator and internal iliac regions; the fluorescence of the removed lymph nodes (LNs) was analyzed on the bench (ex vivo probing). ::: ::: ::: RESULTS ::: : Under in vivo and ex vivo probing, the fluorescence intensity of internal iliac nodes was greater than that of external iliac or obturator nodes. ::: ::: ::: CONCLUSION ::: : The current study suggests that using a FN system after injecting indocyanine green is a safe and rational approach for detecting the lymphatic channel draining from the prostate. The major lymphatic pathway involved in the spreading of prostate cancer appears to relate to internal iliac LNs, which would mean that the standard PLND covering external iliac and obturator regions would not keep the cancer from spreading.
---
paper_title: Image-Guided Oncologic Surgery Using Invisible Light: Completed Pre-Clinical Development for Sentinel Lymph Node Mapping

paper_content:

Background ::: Invisible near-infrared (NIR) fluorescent light permits high sensitivity, real-time image-guidance during oncologic surgery without changing the look of the surgical field. In this study, we complete pre-clinical development of the technology for sentinel lymph node (SLN) mapping using a large animal model of spontaneous melanoma.
---
paper_title: Sentinel Node Navigation Surgery Using Indocyanine Green in Patients with Lung Cancer

paper_content:

PURPOSE ::: To investigate the potential use of sentinel node navigation surgery (SNNS) using indocyanine green (ICG) in lung cancer. ::: ::: ::: METHODS ::: The subjects were 38 patients with stage cN0 lung cancer. After thoracotomy, we injected 5 ml ICG and 400 U hyaluronidase around the tumor, and identified the stained lymph nodes (LNs) intraoperatively by inspection. Postoperatively, we measured ICG concentrations in the dissected LNs. Lymph nodes with an ICG concentration of more than 1.5 times the mean were defined as sentinel nodes (SNs). ::: ::: ::: RESULTS ::: There were 30 pN0, 6 pN1, and 2 pN2 cancers. The tumor size ranged from 11 to 75 (mean 31 +/- 15) mm. Sentinel nodes were identified by inspection in 7 (18.4%) of the 38 patients. Lymphatic mapping with ICG concentration was successful in 38 (100%) of 38. One SN was found in 18 patients and two SNs were found in 20. The SN predicted the status of metastasis of all LNs in 37 (97%) of 38. Metastases were identified in the SN alone in 5 (62.5%) of 8. There was one false negative, caused by a metastatic LN being occupied by tumor cells. ::: ::: ::: CONCLUSION ::: These findings support the efficiency of SNNS for clinically node-negative lung cancer.
---
paper_title: Photo-oxidative killing of human colonic cancer cells using indocyanine green and infrared light

paper_content:

SummaryDespite of the approval of Photofrin® in various countries, chemically defined sensitizers for photodynamic therapy (PDT) are still needed for the absorption of light in the infrared spectrum, which provides a maximal penetration of light into tissue. Therefore, both the efficacy and the mechanism of action of the clinically approved dye indocyanine green (ICG) and laser irradiation were investigated in vitro. For the investigation of phototoxic effects, HT-29 cells were incubated 24 h prior to irradiation by using different concentrations of ICG (10–500 μM). In each experiment, cells were irradiated using a continuous wave (cw)-diode laser (λex = 805 nm, 30 J cm–2, 40 mW cm–2). After laser irradiation, cell viability of dark control and of cells incubated with 500 μM ICG was 1.27 ± 0.11 or 0.28 ± 0.05 respectively. Using 100 μM ICG and D2O, cell viability was further decreased from 0.46 ± 0.03 (H2O) to 0.11 ± 0.01 (D2O). Using D2O and 100 μM ICG, the concentration of malondialdehyde, a marker of lipid peroxidation, increased from 0.89 ± 0.10 nmol 10–6 cells to 11.14 ± 0.11 nmol 10–6 cells. Using 100 μM ICG and laser irradiation sodium azide or histidine (50 mM), quenchers of singlet oxygen reduced the cell killing significantly. In contrast, when using mannitol, a quencher of superoxide anion and hydroxyl radical, cell killing was not inhibited. According to the present results, photoactivated ICG seems to kill colonic cancer cells due to the generation of singlet oxygen and the subsequent formation of lipid peroxides. Therefore, ICG might present a promising photosensitizer for PDT; first clinical results confirm these findings.
---
paper_title: Preliminary safety and efficacy results of laser immunotherapy for the treatment of metastatic breast cancer patients.

paper_content:

We report our preliminary results of a pilot clinical trial of late-stage breast cancer patients treated by laser immunotherapy (LIT), a local intervention using an 805 nm laser for non-invasive irradiation, indocyanine green for selective thermal effect, and immunoadjuvant (glycated chitosan) for immunological stimulation. Ten breast cancer patients were enrolled in this study; all patients were considered to be out of other available treatment options. Toxicity was individually evaluated through physical exams and laboratory tests. Adverse reactions only occurred in the area of treatment due to photothermal injury and local administration of immunoadjuvant. No grade 3 or 4 side effects were observed. Treatment efficacy of LIT was also evaluated by physical examination and tomography. In 8 patients available for evaluation, the objective response rate was 62.5% and the clinical beneficial response rate was 75%. While the study is still ongoing, the initial outcomes of this clinical trial show that LIT is well tolerated and is promising in the treatment of metastatic breast cancer.
---
paper_title: Enhanced Cutaneous Lymphatic Network in the Forearms of Women with Postmastectomy Oedema

paper_content:

Postmastectomy oedema (PMO) of the arm is a common aftermath of axillary lymphatic damage during treatment for breast cancer. The aim of the present study was to quantify the forearm dermal lymphatic
---
paper_title: Sentinel lymph node detection in skin cancer patients using real-time fluorescence navigation with indocyanine green: preliminary experience

paper_content:

Summary Background Sentinel lymph node (SLN) biopsy has become the most widely used procedure to determine the regional lymph node status of patients with cutaneous malignant melanoma, and its application has spread rapidly to other malignancies such as squamous cell carcinoma of the skin, breast cancer and gastric cancer. Objective SLN detection was performed in skin cancer patients using a newly developed real-time fluorescence navigation system with indocyanine green (ICG). Methods SLN biopsy was performed by this method in 10 skin cancer patients (seven with melanoma and three with squamous cell carcinoma). After ICG was injected intradermally around the tumours, the lymphatic drainage was detected and the SLNs were identified by real-time fluorescence imaging. Results The SLNs and their associated subcutaneous lymphatics were successfully identified in all patients. Fluorescence from SLNs was detected by this system for at least 3 hours after the injection of ICG. Conclusion SLN biopsy using ICG fluorescence achieves a high identification rate and allows effective observation for several hours. This method may become a useful option for the detection of SLNs in patients with skin cancer.
---
paper_title: Indocyanine green and laser light for the treatment of AIDS-associated cutaneous Kaposi's sarcoma

paper_content:

Indocyanine green (ICG) is clinically approved for the determination of liver function, cardiac output and plasma volume. In this pilot study, ICG was used as photosensitizer in combination with a diode laser to treat AIDS-associated Kaposi's sarcoma (KS) in three patients. Directly and up to 50 min after intravenous administration of ICG (2-4 mg kg(-1) body weight), KS (n=57), mainly plaque-type, were irradiated using a diode laser (lambda em=805 nm, 100 J cm[-2], 0.5-5 W cm[-2]) matching the absorption maximum. Complete remission of KS (n=16) was achieved when irradiated 1-30 min after injection of the second dose of ICG (2 x 2 mg kg(-1) b.w., 30 min apart) with 3-5 W cm(-2) and 100 J cm(-2). Biopsies (n=3) revealed necrosis of the tumour 24 h and complete remission 4 weeks after therapy. In general, systemic side-effects were not observed and cosmetic results were very good. However, hyperpigmentation occurred temporarily in lesions located on the lower extremities. These findings show that AIDS-associated KS can be effectively treated after photosensitization with ICG and subsequent irradiation with an appropriate diode laser. However, additional investigations need to elucidate the exact mechanism of action of ICG-mediated phototherapy and have to show the efficacy for the treatment of other highly vascularized solid tumours.
---
paper_title: Long-term tumor resistance induced by laser photo-immunotherapy.

paper_content:

An ideal treatment modality for metastasizing tumors should eradicate the primary tumor and elicit a systemic, tumor-selective response leading to elimination of metastases and long-term tumor resistance. Also, it should be induced by local treatment at the primary site, to limit adverse systemic effects. A new method for treating metastatic tumors which utilizes a combination of a near-infrared laser, a photosensitizer and an immunoadjuvant has been developed. It involves intra-tumor injection of the sensitizer/adjuvant solution, followed by local non-invasive laser irradiation. It has produced regression and total eradication of treated primary tumors and untreated metastases at remote sites against mammary tumors in rats. Successfully treated tumor-bearing rats showed total tumor resistance to subsequent tumor rechallenge. Our histochemical results showed that sera from cured tumor-bearing rats contained antibodies that bound strongly to the plasma membrane of both living and preserved tumor cells. Western blot analysis of tumor cell proteins using sera from successfully treated rats as the source of primary antibodies also showed distinct bands, indicating induction of tumor-selective antibodies. Our findings indicate that a systemic, long-term effect on metastatic tumors can be induced by local application of laser photo-immunotherapy.
---
paper_title: Gastric lymphatic basin dissection for sentinel node biopsy using hybrid natural orifice transluminal endoscopic surgery (NOTES).

paper_content:

The aim of the present study was to describe a method of gastric lymphatic basin dissection for sentinel node biopsy using natural orifice transluminal endoscopic surgery with laparoscopic assistance (hybrid NOTES) in a porcine model. Lymph node dissection was performed in three healthy female domestic farm pigs (each around 40 kg) between October, 2007, and December, 2007. The pigs were administered a general anesthetic and laparoscopy-guided transvaginal colpotomy was performed. A two-channel endoscope was then inserted through the incision into the peritoneal cavity via the transvaginal route. An endoscope was inserted simultaneously into the mouth and indocyanine green solution was injected into the submucosal layer of the gastric wall at four sites. Dyed omentum and lymphatics were dissected using a laparoscopic dissector and the grasping forceps of a transvaginal endoscope. Lymphatics and omentum (mean 13.3 cm, range 8-20 cm) were removed transvaginally. The mean number of detected and resected sentinel nodes was 2.6 (range 1-4, diameter 2~12 mm). Sentinel lymphatic basin dissection was performed successfully and without intraoperative complications in all three cases. Hybrid NOTES is technically feasible, and this procedure may represent an alternative to laparoscopic sentinel lymph node dissection of the stomach.
---
paper_title: Laparoscopic detection of sentinel node in gastric cancer surgery by indocyanine green fluorescence imaging

paper_content:

BACKGROUND ::: Indocyanine green (ICG) fluorescence imaging is a promising technique for detection of sentinel node (SN) as it avoids unnecessary resection. However, the ICG fluorescence imaging system cannot be used in laparoscopic surgery because of technological difficulties. ::: ::: ::: METHODS ::: A prototype laparoscopic detection system comprising an electron multiplier charge-coupled device (EM-CCD) as the detector and a xenon lamp as the light source was developed. The CCD camera head was attached to the end of a specially designed laparoscope that could transmit ICG fluorescence. The system allows visualization of both color and fluorescence images. Laparoscopic surgery in ten patients with gastric cancer included SN biopsy using ICG dye, ICG fluorescence images using our system, and laparoscopy-assisted gastrectomy (LAG) with lymphadenectomy. SNs were sliced into 2-mm sections for histological examination and imprint cytology. ::: ::: ::: RESULTS ::: Immediately after intraoperative ICG injection by endoscopy, the laparoscopic ICG fluorescence imaging system allowed easy visualization of the lymphatic vessels draining from the primary gastric tumor toward the lymph nodes and traced the moving injected dye, whereas lymph vessels and nodes were hardly recognized by ICG green color through a standard laparoscope. Surgeons could confirm the removed lymph nodes stained with ICG by fluorescent imaging. SNs were successfully detected in all patients. Three patients had suspicious metastases in the SNs; two patients had lymph node metastases only in the SNs. ::: ::: ::: CONCLUSIONS ::: Our newly developed laparoscopic ICG fluorescence imaging system is promising in the detection of SNs in laparoscopic gastric cancer surgery. The preliminary results suggest an easier and shorter learning curve of dye-guided SN biopsy in laparoscopic gastric surgery.
---
paper_title: Image-Guided Liver Mapping Using Fluorescence Navigation System with Indocyanine Green for Anatomical Hepatic Resection

paper_content:

BACKGROUND ::: In malignant hepatic neoplasm, anatomic resection could improve survival and limit complications from hepatectomy. Our purpose was to develop an intraoperative method for identifying segment and subsegment of the liver with high-sensitivity near-infrared fluorescence imaging. ::: ::: ::: METHODS ::: The subjects were 35 patients with hepatic malignant liver disease who received hepatectomy in 2006. The segments of liver method of identification that used infrared observation camera system termed Photo Dynamic Eye-2 (PDE-2) with indocianine green (ICG) for the patient with malignant liver tumor (hepatocellular carcinoma: 13 cases; metastatic liver cancer: 18 cases; intrahepatic cholangio carcinoma: 4 cases) were performed before liver resection. ::: ::: ::: RESULTS ::: Although greenish stain of the liver surface after the injection of ICG via portal vein is not visible clearly without infrared observation camera system PDE-2, 1 minute after injection of ICG with fluorescent using infrared observation camera system PDE-2, demarcation of liver segment and subsegment was clearly detected. Ten minutes after injection of ICG with fluorescent using infrared observation camera system PDE-2, fluorescence of liver subsegment remained. Stained subsegment and segment of liver were identifiable in 33 (94.3%) of the 35 patients. There were no complications or side-effects related to the injection of patent blue dye. ::: ::: ::: CONCLUSION ::: We demonstrated here that near-infrared fluorescence imaging system is a novel and reliable intraoperative technique to identify hepatic segment and subsegment for anatomical hepatic resection.
---
paper_title: ICG fluorescence endoscope for visualization of the placental vascular network

paper_content:

Intrauterine laser photocoagulation for twin-twin transfusion syndrome (TTTS) needs accurate in-situ recognition of placental vascular anastomosis. Because the conventional procedure is highly dependent upon the operators’ skill and experience, we developed a new way to visualize the placental vascular network by a rigid-type fluorescence endoscope coupled with intravenous administration of Indocyanine green (ICG). The feasibility of the fluorescence endoscope was examined with monkey placentas and pregnant rats. The ICG fluorescence endoscope can visualize the placental vascular network in detail even in the presence of turbid amniotic fluid. Thus, this method is potentially useful for in-situ definition of the placental vascular anastomoses during the treatment for TTTS. In addition, our rigid-type fluorescence endoscope will also be a useful tool for lymph node dissection using ICG by endoscopic surgery.
---
paper_title: Near-infrared (NIR) laparoscopy for intraoperative lymphatic road-mapping and sentinel node identification during definitive surgical resection of early-stage colorectal neoplasia

paper_content:

Background ::: Appropriate lymphatic assessment is a cornerstone of definitive surgical resection for colorectal cancer. Near-infrared (NIR) laparoscopy may allow real-time intraoperative identification of territorial lymphatic drainage and sentinel nodes in patients with early-stage disease prior to radical basin resection.
---
paper_title: Laparoscopic sentinel node mapping for colorectal cancer using infrared ray laparoscopy.

paper_content:

BACKGROUND ::: Sentinel lymph node (SN) mapping by dye injection on conventional laparoscopy (CL) is often precluded by the presence of mesenteric adipose tissue in patients with colorectal cancer. SN mapping on CL was compared with that on infrared ray laparoscopy (IRL) during laparoscopy-assisted colectomy (LAC). ::: ::: ::: PATIENTS AND METHODS ::: Forty-eight patients with colorectal cancer who underwent LAC were enrolled. The tumor was identified by intra-operative fluoroscopy with marking clips. The tumor was stained intra-operatively by peritumoral injection of indocyanine green dye. SNs were observed by CL and by IRL. ::: ::: ::: RESULTS ::: In all 48 patients, dye injection and tumor localization during LAC were successful. The identification of SNs on IRL was approximately five times better than that on CL. There were no false-negative cases in T1 and T2 disease by IRL. ::: ::: ::: CONCLUSION ::: SN mapping on IRL is superior to that on CL. SN mapping by IRL might be feasible for T1 and T2 tumors.
---
paper_title: Real-time intra-operative near-infrared fluorescence identification of the extrahepatic bile ducts using clinically available contrast agents.

paper_content:

BACKGROUND ::: Iatrogenic bile duct injuries are serious complications with patient morbidity. We hypothesized that the invisible near-infrared (NIR) fluorescence properties of methylene blue (MB) and indocyanine green (ICG) could be exploited for real-time, intraoperative imaging of the extrahepatic bile ducts during open and laparoscopic surgeries. ::: ::: ::: METHODS ::: In all, 2.0 mg/kg of MB and 0.05 mg/kg of ICG were injected intravenously into 35-kg female Yorkshire pigs and the extrahepatic bile ducts were imaged over time using either the Fluorescence-Assisted Resection and Exploration (FLARE) image-guided surgery system (open surgery) or a custom NIR fluorescence laparoscopy system. Surgical anatomy was confirmed using x-ray cholangiography. The contrast-to-background ratio (CBR), contrast-to-liver ratio (CLR), and chemical concentrations in the cystic duct (CD) and common bile duct (CBD) were measured, and the performance of each agent was quantified. ::: ::: ::: RESULTS ::: Using NIR fluorescence of MB, the CD and CBD could be identified with good sensitivity (CBR and CLR > or =4), during both open and laparoscopic surgeries, from 10 to 120 min postinjection. Functional impairment of the ducts, including constriction and injury were immediately identifiable. Using NIR fluorescence of ICG, extrahepatic bile ducts did not become visible until 90 min postinjection because of strong residual liver retention; however, between 90 and 240 min, ICG provided exquisitely high sensitivity for both CD and CBD, with CBR > or =8 and CLR > or =4. ::: ::: ::: CONCLUSION ::: We demonstrate that 2 clinically available NIR fluorophores, MB fluorescing at 700 nm and ICG fluorescing at 800 nm, provide sensitive, prolonged identification of the extrahepatic bile ducts and assessment of their functional status.
---
paper_title: Laparoscopic Findings in an Adult Case of Alagille Syndrome

paper_content:

Laparoscopic findings in a 32-year-old woman presenting with Alagille syndrome are reported. The liver surface showed a segmental whitish discoloration on the surface of both lobes with a transverse sulcus which was not stained enough after an intravenous injection of indocyanine green (ICG). These findings suggested an acquired bile duct injury in addition to a congenital anomaly of the bile duct in this patient.
---
paper_title: Feasibility of laparoscopic sentinel basin dissection for limited resection in early gastric cancer

paper_content:

BACKGROUND ::: The clinical applications of sentinel node (SN) biopsies in early gastric cancer are limited because of low sensitivity. Sentinel basin (SB) dissection has been suggested as alternative to SN biopsy to improve sensitivity. The aim of this study was to examine the feasibility of laparoscopic SB dissection. ::: ::: ::: METHODS ::: Twenty-one gastric adenocarcinoma patients of cT1N0 were enrolled. Technetium 99 m human serum albumin and indocyanine green were injected into the submucosal layer around tumor using an intraoperative endoscope. Green-stained or radioactive lymphatic basins were detected and defined as SBs. After laparoscopic SB dissection, laparoscopy-assisted gastrectomy with D2 lymphadenectomy was performed. Dissected SB nodes and non-SB nodes were evaluated for metastasis pathologically. ::: ::: ::: RESULTS ::: The SB detection rate was 95.2%. Numbers of SBs were one in 6, two in 10, and three in 4 patients. The mean number of SB nodes was 7.0. Two patients with lymph node metastasis were diagnosed by SB dissection. Mean time of laparoscopic SB dissection procedure was 15.2 min. ::: ::: ::: CONCLUSIONS ::: Above findings suggest that laparoscopic SB dissection is technically feasible, and it might have better sensitivity than SN biopsy. However, the validity of this procedure should be evaluated in a larger series before being clinically applied.
---
paper_title: Laparoscopic Findings in Primary Sclerosing Cholangitis

paper_content:

: The laparoscopic appearance of the liver surface in patients with primary sclerosing cholangitis (PSC) has not been fully delineated. We examined 5 patients with PSC and reviewed 35 previously reported cases. Intense white markings in a mesh-like pattern were characteristic of PSC. The findings varied depending on the histologic stage and affected site. Red patches which have also been seen in primary biliary cirrhosis (PBC), green patches indicating cholestasis, and dilatation of the terminal bile ducts were also observed. The red patches were wider than those in PBC. The white markings were less well defined in the red patches than in other areas. The severity of the fibrosis and histologic damage was judged to be mild at the red sites. The green patches were caused by localized cholestasis. This indicated that PSC unevenly affects the liver. Severe obstruction may be present between the interlobular bile ducts and the septal bile ducts in anicteric stages. (Dig Endosc 1999; 10: 37–41)
---
paper_title: Intraoperative exploration of biliary anatomy using fluorescence imaging of indocyanine green in experimental and clinical cholecystectomies.

paper_content:

BACKGROUND/PURPOSE ::: We evaluated the usefulness of intraoperative exploration of the biliary anatomy using fluorescence imaging with indocyanine green (ICG) in experimental and clinical cholecystectomies. ::: ::: ::: METHODS ::: The experimental study was done using two 40-kg pigs and the clinical study was done in 12 patients for whom cholecystectomy was planned from January 2009 to June 2009. Initially we used a laparoscopic approach for the evaluation of fluorescence imaging of the biliary system in the two pigs. Then the clinical study was started on the basis of these experimental results. ICG (1.0 ml/body of 2.5 mg/ml ICG) was infused 1-2 h before surgery. With the subjects under general anesthesia we observed in real time the condition of the biliary tract under the guidance of fluorescence imaging employing an infrared camera or a prototype laparoscope. ICG was added intravenously to observe the location or flow condition of the cystic artery. ::: ::: ::: RESULTS ::: We obtained a clear view of the biliary tract and the location of the cystic duct in the two pigs. Local compression with a transparent hemispherical plastic device was effective for offering a clearer view. The biliary tract, except for the gallbladder, was clearly recognized in all clinical subjects. Local compression with a transparent hemispherical plastic device for open cholecystectomy and a flat plastic device for laparoscopy provided clearer visualization of the confluence between the cystic duct and common bile duct or common hepatic duct. The location of the cystic artery was revealed after division of the connective tissues, and the flow condition of the cystic artery was confirmed 7-10 s after intravenous re-infusion of ICG. There were no adverse events related to the intraoperative procedure or the ICG itself. ::: ::: ::: CONCLUSIONS ::: This method is safe and easy for the identification of the biliary anatomy, without requiring cannulation into the cystic duct, X-ray equipment, or the use of radioactive materials. Although fluorescence imaging is still at an early stage of application in comparison with ordinary intraoperative cholangiography, we expect that this method will become routine, offering a lower degree of invasiveness that will help avoid bile duct injury.
---
paper_title: Effect of liver blood flow and function on hepatic indocyanine green clearance measured directly in a cirrhotic animal model

paper_content:

Background: Peripheral blood clearance of indocyanine green (ICG) has been used as a test of liver function but gives little information on biliary excretion. Hepatic ICG uptake and clearance can be measured directly by near-infrared spectroscopy (NIRS). Direct ICG measurement has not previously been correlated with liver blood flow and function in cirrhosis.Methods: Two groups of New Zealand white rabbits (n =12) underwent laparotomy for liver exposure. Cirrhosis was induced by feeding animals (n = 6) with a high-cholesterol (2 per cent) diet for 16 weeks. Hepatic blood flow and microcirculation were measured, Hepatic ICG concentration was measured directly using NIRS probes on the liver surface. From the ICG concentration-time curve, hepatic ICG uptake and excretion rates were calculated by a non-linear least square curve fitting method.Results: There was a significant reduction in ICG uptake rate (mean(s.d.) 0.300(0.130) versus 2.040(0.420) min(-1); P= 0.0001) and ICG excretion rate (0.007(0.009) versus 0.227(0.096) min(-1); P = 0.002) in cirrhotic animals. The hepatic ICG uptake rate correlated with hepatic blood flow and flow in the microcirculation (r = 0.81, P = 0.002; r = 0.92, P < 0.001, respectively). The hepatic ICG excretion rate was significantly associated with indicators of impaired liver function including bilirubin (r = -0.86, P = 0.0004), aspartate aminotransferase (r = -0.81, P = 0.001) and lactate dehydrogenase (r = -0.83, P=0.0008).Conclusion: ICG uptake measured directly by NIPS reflects the reduced liver blood how and perfusion in cirrhosis and its excretion correlates with the degree of liver parenchymal dysfunction, This technique may allow a more accurate method of liver function assessment than peripheral blood ICG clearance.
---
paper_title: Indocyanine green‐fluorescent imaging of hepatocellular carcinoma during laparoscopic hepatectomy: An initial experience

paper_content:

Introduction: Laparoscopic hepatectomy has disadvantages in intraoperative diagnosis, because it offers limited visualization and palpability of the liver surface. Recently, we developed a novel fluorescent imaging technique using indocyanine green (ICG), which would enable identification of liver cancers during open hepatectomy. However, this technique has not yet been applied to laparoscopic hepatectomy. ::: ::: ::: ::: Materials and Surgical Technique: A patient with a hepatocellular carcinoma (HCC) located in Couinaud's segment II was administered ICG (0.5 mg per kg body weight) intravenous injection 5 d before surgery, as a routine liver function test. The prototype fluorescent imaging system was composed of a xenon light source and a laparoscope with a charge-coupled device camera that could filter out light with wavelengths below 810 nm. Intraoperatively, fluorescent imaging of the HCC was performed by changing color images to fluorescent images with a foot switch. Then, the fluorescing tumor was clearly identified on the visceral surface of segment II during mobilization of the left liver for resection of segments II and III. On the cut surface of the specimen, the tumor showed uniform fluorescence and was microscopically diagnosed as a well-differentiated HCC. ::: ::: ::: ::: Discussion: Laparoscopic fluorescent imaging using preoperative injection of ICG enabled real-time identification of HCC. This technique may be an easy and reliable tool to enhance the accuracy of intraoperative diagnosis during laparoscopic hepatectomy.
---
paper_title: Which biopsy method is more suitable between a basin dissection and pick-up biopsy for sentinel nodes in laparoscopic sentinel-node navigation surgery (LSNNS) for gastric cancer?

paper_content:

BACKGROUND ::: Sentinel-node navigation surgery (SNNS) for breast cancer and melanoma has been accepted as a reasonable oncologic surgery worldwide. On the other hand, in gastric cancers that do metastasize well to the lymph node, the use of SNNS has been approached with care and performed in only limited cases. Some obstacles still have to be overcome, such as the shortcomings of SN tracers and the technical limitations of laparoscopic SN detection. The aims of this study were to determine whether laparoscopic SNNS is possible, and which biopsy method is more suitable for SN tracers, in gastric cancer, preoperatively diagnosed as < or =T2 and with < or =4-cm-sized lesions. ::: ::: ::: MATERIALS AND METHODS ::: Between January 2005 and October 2006, 92 consecutive patients that underwent LSNNS, using a combined indocyanine green and (99m)Tc-labeled tin colloid technique, were prospectively studied. SNs were laparoscopically removed by using two biopsy methods: a basin dissection and pick-up method, with the results of these two SN biopsy methods then compared with the final diagnosis obtained from a permanent section. ::: ::: ::: RESULTS ::: With the pick-up method, SNs were identified in 23 of 42 patients (54.8%); however, with basin dissection, the detection rate was 96% (48 of 50 patients). The average number of SNs detected by the two methods were 2.1 (range, 0-4) and 3.5 (range, 1-7), respectively. The sensitivities of the two methods were 66% (4/6) and 85.7% (12/14), with specificities of 100% (17/17) and 100% (34/34), respectively. ::: ::: ::: CONCLUSION ::: In gastric cancer, it was possible to perform LSNNS. At this moment, we believe the laparoscopic basin dissection technique with a dual-tracer injection, followed by SN detection on the back table, will be a reasonable procedure for gastric cancer, owing to the shortcomings related to the dye and radioisotope, the so-called "stained lymphatic duct only" and "shine-through phenomenon."
---
paper_title: A novel image-guided surgery of hepatocellular carcinoma by indocyanine green fluorescence imaging navigation

paper_content:

BACKGROUND AND OBJECTIVES ::: The clear delineation between tumor and normal tissue is ideal for real-time surgical navigation imaging. We present a novel indocyanine green (ICG) fluorescence imaging technique to visualize hepatocellular carcinoma (HCC). ::: ::: ::: METHODS ::: Ten patients with solitary HCC underwent hepatectomy between February and September 2007 at Osaka Medical Center for Cancer and Cardiovascular Diseases. ICG had been injected intravenously several days before surgery at a dose of 0.5 mg/kg body weight. After laparotomy, the liver was inspected with intraoperative ultrasonography (IOUS), and then with a near-infrared (NIR) fluorescence imaging system (PDE; Hamamatsu Photonics K.K. Hamamatsu, Japan). ::: ::: ::: RESULTS ::: All the 10 primary tumors showed bright fluorescent signals and could be completely removed with negative margins under the guide of PDE. In four cases (40.0%), new HCC nodules that were not detected by use of any preoperative examinations including IOUS were detected by PDE. These newly identified HCC nodules were very small in size and most of the tumors were well-differentiated HCCs. ::: ::: ::: CONCLUSIONS ::: This novel technique is simple and safe, and is therefore considered to be a promising tool for routine intraoperative imaging during a hepatic resection and further clinical exploration for HCC.
---
paper_title: Sentinel node mapping guided by indocyanine green fluorescence imaging in gastric cancer.

paper_content:

OBJECTIVE ::: In this study, we determined the possible usefulness of sentinel node (SN) mapping guided by indocyanine green (ICG) fluorescence imaging in the management of gastric cancer. ::: ::: ::: SUMMARY BACKGROUND DATA ::: ICG fluorescence imaging system has recently been developed for obtaining biochemical information from living tissues. ::: ::: ::: METHODS ::: Our series consisted of 56 patients with gastric cancer who underwent standard gastrectomy with lymphadenectomy. Two milliliters of ICG solution (0.5%) was injected into the submucosa around the tumor endoscopically before the operation or into the subserosa intraoperatively. ICG fluorescence imaging was conducted using a charge-coupled device camera with a light-emitting diode having a wavelength of 760 nm as the light source and a cut filter to filter out light with wavelengths below 820 nm as the detector. ::: ::: ::: RESULTS ::: SNs were detected in 54 (96.4%) of the 56 patients, and the mean number of SNs was 7.2 +/- 7.0. Even SNs that were not green in color could be easily and clearly visualized by ICG fluorescence imaging. cT1-stage cancers were associated with a significantly higher accuracy rate (97.2% vs. 72.2%, P = 0.0127) than cT2-or cT3-stage cancers. Preoperative ICG injection was associated with a significantly higher incidence of cT1-stage cancers (87.1% vs. 40.0%, P = 0.0004), a larger mean number of SNs (9.9 +/- 7.5 vs. 4.1 +/- 5.0, P < 0.0001), a higher accuracy rate (100% vs. 73.9%, P = 0.0039), and a lower false negative rate (0% vs. 60.0%, P = 0.0345) as compared with intraoperative ICG injection. ::: ::: ::: CONCLUSIONS ::: This study shows that ICG fluorescence imaging allows highly sensitive image-guided intraoperative SN mapping in cases of gastric cancer. Our data suggest that SN mapping guided by ICG fluorescence imaging might be useful for predicting the metastatic status in lymph nodes in cases of gastric cancer, especially those with cT1-stage cancer.
---
paper_title: Sinusoidal perfusion in the veno-occlusive region of living liver donors evaluated by indocyanine green and near-infrared spectroscopy.

paper_content:

Split liver transplantation and living donor liver transplantation (LDLT) commonly use a right liver graft without the middle hepatic vein (MHV). Although tributaries of the MHV are not reconstructed in the majority of cases, the alterations of the microcirculation and its regional functions remain unknown. We addressed these issues by assessing liver tissue indocyanine green (ICG) uptake with near-infrared spectroscopy (NIRS) in 21 donors. After graft procurement, visual inspection (before and after hepatic arterial clamping) and Doppler examination of the veno-occlusive region were performed. Bolus ICG (100 microg/kg) was then administered intravenously. Blood ICG at the finger tip was measured with pulse dye densitometry, whereas the liver ICG concentrations in the veno-occlusive and non-veno-occlusive regions were simultaneously measured for 15 minutes by NIRS. We estimated the hepatic ICG uptake rate constants in the veno-occlusive region (Ku-oc) and non-veno-occlusive region (Ku-non). Changes in sinusoidal perfusion in the veno-occlusive region were expressed by the ratio of Ku-oc to Ku-non (Roc/non). The median value of Roc/non was 0.47, although it ranged from 0.13 to 0.94. Roc/non was related to the extent of liver surface discoloration before and after hepatic arterial clamping (P = 0.03 and 0.01, respectively). In conclusion, sinusoidal perfusion was impaired in the veno-occlusive regions of living donor livers, but the magnitude of the effect varied greatly. Measurement of hepatic ICG uptake by NIRS could become a valuable tool for assessing the indication for venous reconstruction in LDLT and/or split donor liver transplantation.
---
paper_title: Fluorescent cholangiography illuminating the biliary tree during laparoscopic cholecystectomy

paper_content:

BACKGROUND ::: Although intraoperative cholangiography has been recommended for avoiding bile duct injury during laparoscopic cholecystectomy, radiographic cholangiography is time consuming and may itself cause injury to the bile duct. Recently, a novel fluorescent cholangiography technique using the intravenous injection of indocyanine green (ICG) has been developed. ::: ::: ::: METHODS ::: In 52 patients undergoing laparoscopic cholecystectomy, 2.5 mg ICG was injected intravenously 30 min before the patient entered the operating room or following intubation. A fluorescent imaging system, which consisted of a xenon light source and a laparoscope with a charge-coupled device camera that could filter out light wavelengths below 810 nm, was used. Fluorescent cholangiography was performed during dissection of Calot's triangle, and its ability to delineate biliary anatomy was compared with that of preoperative cholangiography. ::: ::: ::: RESULTS ::: Fluorescent cholangiography delineated the cystic duct in all 52 patients, and the cystic duct-common hepatic duct junction was visible before dissection of Calot's triangle in 50 patients. Fluorescent imaging also identified all accessory bile ducts that had been diagnosed before surgery in eight patients. ::: ::: ::: CONCLUSION ::: Fluorescent cholangiography enables real-time identification of biliary anatomy during dissection of Calot's triangle. This simple technique may become standard practice for avoiding bile duct injury during laparoscopic cholecystectomy, replacing radiographic cholangiography.
---
paper_title: Assessment of the patency of microvascular anastomoses using microscope-integrated near-infrared angiography: A preliminary study

paper_content:

BACKGROUND ::: : Technical problems at the site of the anastomosis compromise an underappreciated proportion of microsurgical free tissue transfers. Intraoperative identification of technical errors may be able to prevent reexploration surgery and early flap failure. We report the first human study on a new microscope-integrated fluorescence angiography technique, which allows for intraoperative imaging of the anastomotic site. ::: ::: ::: METHODS ::: : Fifty consecutive patients undergoing reconstructive microsurgical procedures were enrolled in the study. Intraoperative near infrared indocyanine green videoangiography (ICGA) was performed on all microsurgical anastomoses, after they had been assessed by the operating surgeon by conventional clinical patency tests. Anastomoses deemed to be occluded by the ICG-angiography were intraoperatively revised, and the result of revision was compared with angiographic findings. ::: ::: ::: RESULTS ::: : In 11/50 (22%) of patients, where the surgeon had classified the anastomoses as patent, microangiography identified a total luminal occlusion (six) and/or significant alterations in blood flow (five), potentially predisposing toward postoperative flap failure. Intraoperative revision confirmed angiographic findings in 100% of cases, and was always associated with flap survival. The decision not to revise despite anastomotic occlusion by the intraoperative angiogram was always followed by flap loss or early reexploration. A delayed return of venous blood from the flap predisposed toward postoperative flap failure. ::: ::: ::: CONCLUSIONS ::: : Hand-sewn anastomoses are subject to technical errors, and conventional patency tests have a low sensitivity for revealing anastomotic failure. Microscope integrated microangiography is an excellent method for identifying significant anastomotic problems, which would have otherwise gone unnoticed. The potential impact on early flap failure and reexploration surgery is considerable. (c) 2009 Wiley-Liss, Inc. Microsurgery 2009.
---
paper_title: Intraoperative evaluation of skin-flap viability using laser-induced fluorescence of indocyanine green.

paper_content:

Laser-induced fluorescence of indocyanine green (ICG) is a new method for evaluating skin perfusion, which is superior to conventional fluorescein angiography. In a prospective clinical study ICG fluorescence video-angiography was used for the intraoperative evaluation of skin-flap perfusion. The results of ICG imaging were compared with clinical outcome 1 week postoperatively. Intraoperative ICG filling defects were always associated with delayed wound healing. In 50% of the patients, the regions of sloughing and epitheliolysis corresponded accurately to the regions of dye-filling deficits. All of the flaps without ICG filling defects healed primarily. These results suggest that ICG fluorescence is a sensitive tool for assessing nutritive blood flow in pedicled skin flaps with and without an axial vessel. Future clinical studies are required to establish critical threshold fluorescence indices that correlate with skin viability in the postoperative course.
---
paper_title: The FLARE intraoperative near-infrared fluorescence imaging system: a first-in-human clinical trial in perforator flap breast reconstruction.

paper_content:

BACKGROUND ::: The ability to determine flap perfusion in reconstructive surgery is still primarily based on clinical examination. In this study, the authors demonstrate the use of an intraoperative, near-infrared fluorescence imaging system for evaluation of perforator location and flap perfusion. ::: ::: ::: METHODS ::: Indocyanine green was injected intravenously in six breast cancer patients undergoing a deep inferior epigastric perforator flap breast reconstruction after mastectomy. Three dose levels of indocyanine green were assessed using the fluorescence-assisted resection and exploration (FLARE) imaging system. This system uses light-emitting diodes for fluorescence excitation, which is different from current commercially available systems. In this pilot study, the operating surgeons were blinded to the imaging results. ::: ::: ::: RESULTS ::: Use of the FLARE system was successful in all six study subjects, with no complications or sequelae. Among the three dose levels, 4 mg per injection resulted in the highest observed contrast-to-background ratio, signal-to-background ratio, and signal-to-noise ratio. However, because of small sample size, the authors did not have sufficient power to detect statistical significance for these pairwise comparisons at the multiple-comparison adjusted type I error of 0.017. Six milligrams per injection provided a similar contrast-to-background ratio but also a higher residual background signal. ::: ::: ::: CONCLUSION ::: Based on this pilot study, the authors conclude that near-infrared assessment of perforator flap breast reconstruction is feasible with a light-emitting diode-based system, and that a dose of 4 mg of indocyanine green per injection yields the best observed contrast-to-background ratio compared with a dose of 2 or 6 mg for assessment of flap perfusion.
---
paper_title: Modalities for the Assessment of Burn Wound Depth

paper_content:

OBJECTIVE ::: Burn wound depth is a significant determinant of patient treatment and morbidity. While superficial partial-thickness burns generally heal by re-epithelialization with minimal scarring, deeper wounds can form hypertrophic or contracted scars, often requiring surgical excision and grafting to prevent a suboptimal result. In addition, without timely intervention, more superficial burn wounds can convert to deeper wounds. As such, the rapid and accurate assessment of burn wound depth is a priority in treating burn-injured patients. The object of this article is to review current research on modalities useful in the assessment of burn wound depth with emphasis on the relative costs and benefits of each technique. ::: ::: ::: METHODS ::: PubMed and Cochrane computerized databases were used for data retrieval, using the search terms "burns," "burn wounds," "burn depth," "burn depth measurement," and "burn depth progression." In addition, bibliographic references from prior reviews of burn depth were reviewed. All peer-reviewed, English-language articles relevant to the topic of burn depth measurement were reviewed, including those focusing on animal and human populations. Where appropriate, conclusions drawn from review articles and expert analyses were included. ::: ::: ::: RESULTS ::: Although bedside evaluation remains the most common modality of diagnosing the depth of burn wounds, recent technological advances have broadened the scope of depth assessment modalities available to clinicians. Other depth assessment techniques include biopsy and histology, and perfusion measurements techniques such as thermography, vital dyes, indocyanine green video angiography, and laser Doppler techniques. ::: ::: ::: CONCLUSION ::: Of the depth assessment modalities currently used in clinical practice, LDI and ICG video angiography offer the best data-supported estimates of accuracy. Until the future of new modalities unfolds, a combination of clinical evaluation and another modality--thermography, biopsy, or, ideally, ICG video angiography or LDI--is advised to best assess the depth of acute burn wounds.
---
paper_title: Outcome Prediction in Microsurgery by Quantitative Evaluation of Perfusion Using ICG Fluorescence Angiography

paper_content:

The purpose of this prospective study was to evaluate the clinical efficacy of laser-induced fluorescence angiography with indocyanine green (ICG-FA) for perioperative monitoring of tissue perfusion in hand surgery. Different quantitative parameters of the uptake, distribution and clearance of dye-marked blood were evaluated for their sensitivity and prognostic value in comparison to each other and to clinical parameters. One hundred and fifty-five measurements were performed prior to, or following, surgery for severe hand injuries. All quantitative parameters of ICG-FA detected intraoperatively were found to be of significant predictive value for outcome, but clinical parameters were not. For the dye uptake, a minimum slope value of 0.01 was significantly related to sufficient perfusion and good prognosis. There was no correlation between the quantitative ICG-FA results or any of the clinical parameters. Since clinical evaluation of perfusion in this surgery remains difficult, the additional use of ICG-FA may improve surgical decision making and, thereby, lead to better clinical results.
---
paper_title: The Application of Laser-Assisted Indocyanine Green Fluorescent Dye Angiography in Microsurgical Breast Reconstruction

paper_content:

The benefits of laser-assisted indocyanine green fluorescence angiography have previously been demonstrated in cardiac surgery. The purpose of this study was to determine the value of this technology in microsurgical breast reconstruction. Intraoperative laser-assisted indocyanine green fluorescence angiography was performed on all microsurgical breast reconstruction cases (deep inferior epigastric perforator flap or free transverse rectus abdominus muscle flap) during the study period. Ten consecutive free tissue transfer autologous breast reconstructions were performed on 8 women. In four cases, imaging demonstrated flow or perfusion deemed "marginal" or "poor" by the operating surgeons. In three of these cases, one involving poor arterial inflow, one of poor venous outflow, and one of poor perfusion of a mastectomy flap, the intraoperative plan was adjusted accordingly and follow-up imaging demonstrated improvement. In the fourth case, no adjustment was made at operation. However this patient required a return to the operating room for venous congestion of the flap, which was corrected without sequela. Overall flap survival was 100%. We concluded that laser-assisted indocyanine green fluorescence angiography appears to provide important information that has helped guide intraoperative decision making in our series.
---
paper_title: Endoscopic measurements of free-flap perfusion in the head and neck region using red-excited Indocyanine Green: preliminary results

paper_content:

Summary Background Free-tissue transfer has become a standard procedure for reconstructive surgery in the head and neck area. Flap failures are relatively rare (≤5%), and a high percentage can be salvaged if detected early. Indocyanine Green (ICG) angiography might be able to improve the detection of flap malperfusion at an early stage. Methods So far, 11 patients with free-flap reconstructions of the upper aerodigestive tract (UADT) have participated in this study. Each participant underwent three endoscopic ICG angiographies (24h intra-operatively and 72h postoperatively). The data obtained were evaluated online as well as offline on a personal computer (PC), and the results compared to the clinical outcome. Results There were no partial or complete flap losses. One flap was successfully salvaged following initial arterial kinking with impeded perfusion. The ICG fluorescence angiography was tolerated well in all patients. The free flaps showed a delayed yet equal ICG fluorescence as compared to the surrounding tissue. The timing and slope of fluorescence build-up were dependent on circulatory factors. The relative fluorescence maxima of flap versus surrounding were 33% in the initially failing flap and ≥64% for all other examinations. Conclusions It was possible to prove the feasibility of endoscopic ICG fluorescence angiography in patients undergoing free-flap transfer to the UADT. The method provides instant information about the perfusion state of the tissue and is easily performed without greater patient discomfort or risk of side effects. Due to the endoscopic approach, the method seems highly promising for this indication and merits further evaluation.
---
paper_title: Searching for the right timing of surgical delay: angiogenesis, vascular endothelial growth factor and perfusion changes in a skin-flap model.

paper_content:

BACKGROUND ::: The angiogenic potential of vascular endothelial growth factor (VEGF) and its oxygen pressure-dependent regulation suggest a strong connection between this growth factor and the 'delay phenomenon'. In this study we focused on the chronological changes in VEGF concentration and flap perfusion in order to optimise the duration of surgical delay. ::: ::: ::: METHODS ::: The VEGF concentration in skin and underlying muscle was measured in oversized, random-pattern flaps on 38 male Sprague-Dawley rats after 3, 5 or 7 days of surgical delay. Additionally, flaps were raised 5 or 7 days past preconditioning. The effect on flap perfusion was measured using indocyanine green fluoroscopy and the size of surviving and necrotic areas of the flaps were analysed. Microvessel density was assessed using a monoclonal CD31 antibody, and vessel diameter and morphometry were appraised by means of corrosion casting. ::: ::: ::: RESULTS ::: VEGF expression in the distal half of the flaps was significantly increased 3 days after preconditioning and perfusion was significantly enhanced after day 5. An interval of 5 days between preconditioning and flap transposition resulted in a significantly reduced average necrosis rate. Microvessel density was significantly increased and vessel diameters were enlarged (P<0.05). ::: ::: ::: CONCLUSIONS ::: We illustrated the chronology of events from the ischaemic procedure to the rise in VEGF concentration and changes in flap perfusion, and demonstrated vasodilatation and the formation of new vessels. Most significantly, we were able to further specify the optimal length of surgical delay based on alterations on a molecular level as well as changes in vascularisation and perfusion.
---
paper_title: Prediction of flap necrosis with laser induced indocyanine green fluorescence in a rat model.

paper_content:

Prediction of necrosis has a clinical relevance in all fields of plastic surgery. The new application of indocyanine green (ICG) fluoroscopy in plastic surgery allows an objective quantification of skin perfusion and a high topographical resolution. The aim of the present study is to determine threshold values for flap perfusion under well-defined experimental conditions. Twenty random pattern flaps with a length to width ratio of 4:1 (8 x 2 cm(2)) were dissected on the anterior abdominal wall of 20 male Sprague-Dawley rats. ICG fluoroscopy was performed at the end of the operation. The animals were sacrificed at the seventh postoperative day with a reliable necrosis of the distal part of the flaps. Postoperative ICG fluoroscopy then was analysed both in regions that will survive and undergo necrosis. At day 7 a mean area of 5.5 cm(2) (57% of the total flap area) survived and a mean of 3.8 cm(2) (43%) became necrotic. The surviving part of the flap had a mean perfusion index of 62% compared to reference skin. The distal parts of the flap that necrotised showed an average perfusion index of only 19% postoperatively. Differences were statistically highly significant (p<0.001). Indocyanine green fluoroscopy is a useful tool to evaluate perfusion topographically and predict necrosis. From a statistical point of view a perfusion index of less than 25% of the reference skin can be considered as a sign of developing flap necrosis.
---
paper_title: Indocyanine green video angiographies help to identify burns requiring operation.

paper_content:

The key decision in the treatment of thermal injuries is the determination of the depth of the burn wound and the resultant decision on treatment options. The trend in the treatment of deep dermal and full thickness burns is toward very early excision and grafting to reduce the risk of infection, decrease scar formation, shorten hospital stay, and thereby reducing costs. Traditionally, this has involved serial clinical examinations, which involves primarily subjective judgment. Various objective examination techniques, supplementing the clinical diagnosis, have been suggested, but none has yet achieved widespread clinical acceptance. It has frequently been postulated that the blood flow in injured tissue indicates the extent of tissue damage. In this study, the clinical and scientific impact of indocyanine green (ICG) video angiography was tested in 20 patients. A wide range of depth of injury and etiology was included and analyzed. In all cases considered, video angiography was possible. The measurements and observations correlated well with the actual burn depth, which was assessed clinically (pre- and intraoperative assessment) and histologically (biopsies). In conclusion, ICG video angiography seems to be a practical method to describe vascular patency in a burn wound. The results indicate that ICG fluorescence angiography is a practical, accurate, and effective adjunct to clinical methods for estimating burn wound depth and thereby to assist in the rational assessment of treatment options. Furthermore, it allows an objective, qualitative and quantitative observation of the dynamic changes in burn wound depth, which are observed during the acute post-burn period, thereby indicating optimal timing of the first operation.
---
paper_title: An alternative tool for intraoperative assessment of renal vasculature after revascularization of a transplanted kidney

paper_content:

Abstract Intraoperative assessment of flow in the renal artery and vein after reconstruction is a crucial matter in kidney transplantation. Conventional Doppler ultrasound detects blood flow only in a limited area. The authors report a newly developed device that noninvasively visualizes the condition of perfusion of an entire allograft at one time from any angle and also clearly detects the state of anastomosis of the renal vessels. This near-infrared camera system provides the opportunity for the intraoperative assessment of the vasculature of renal allografts.
---
paper_title: The "perfusion map" of the unipedicled TRAM flap to reduce postoperative partial necrosis.

paper_content:

The unipedicled transverse rectus abdominis musculocutaneous (TRAM) flap is a well-known technique for breast reconstruction. However, it is clinically difficult to evaluate the blood perfusion of the flap in the operating room. A new technique of blood supply evaluation, employing indocyanine green dye (ICG) fluorescence videoangiography has been performed in 10 cases of unipedicled TRAM flap breast reconstruction. In our series, the ICG measurement was demonstrated to be a safe, quick, and accurate technique of flap perfusion analysis. We confirmed the presence of individual pattern ("perfusion map") of the flap perfusion, zone II sometimes not being as well perfused as zone III. In this paper, we present our descriptive findings, and the ICG analysis seems to have a predictive value of unipedicled TRAM flap viability.
---
paper_title: The role of near-infrared angiography in the assessment of post-operative venous congestion in random pattern, pedicled island and free flaps

paper_content:

Summary Indocyanine green near-infrared-video angiography (ICG-NIR-VA) was recently introduced for measuring perfusion of skin flaps. The prognostic value of this method with regards to post-transfer manipulations of the flap, and subsequently, flap survival is not adequately documented in the literature. In this paper, we report our experience with the ICG-NIR-VA in the intraoperative evaluation and post-operative follow-up of nine flaps (2 large random pattern, 4 pedicled island and 3 free flaps) used in various reconstructive procedures. Two flaps (1 random pattern and 1 free flap) showed delayed intraoperative uptake in ICG-NIR-VA. In the post-operative phase, (days 1–3) six flaps (1 random pattern, 2 axial pattern and 3 free flaps) showed a delay both in the ICG-NIR-VA uptake, as well as clearance. However, a clinical correlate was observed only in 2 of the 6 flaps demonstrating this delay: general and partial venous congestion was seen in a distally based interosseous posterior flap and a free lateral arm flap respectively. Leeches were implemented only based on the clinical signs. In one distally based perforator flap, the decision on perfusion augmentation via microanastomosis was based on the intraoperative ICG-NIR-VA finding. All flaps showed uneventful healing. Based on our observations, the question arises, not whether the ICG-NIR-VA is sensitive for the prognosis of venous congestion, upon which the flap manipulation strategy might rest—but whether it is too sensitive. Further, prospective studies are necessary.
---
paper_title: Monitoring free flaps using laser‐induced fluorescence of indocyanine green: A preliminary experience

paper_content:

In a prospective, clinical study, the clinical utility of indocyanine green for intraoperative monitoring of free tissue transfer was evaluated. The study comprised 20 surgical patients undergoing elective microsurgical procedures. Indocyanine green angiography was performed intraoperatively, immediately after flap inset, and the operating team was blind to the fluoremetric findings. Thereafter, postoperative monitoring was done exclusively by clinical examination (color, temperature, time for recapillarization, and bleeding after puncture). Final outcome was compared with results of perioperative indocyanine (ICG)-imaging, and classified either as total flap loss, partial flap loss, or successful tissue transplantation. A total of 2 (10%) complications was recorded, and included one partial and one total flap loss. Both complications were detected by intraoperative ICG imaging. Another case of intraoperative subclinical arterial spasm at the place of microvascular anastomosis was revealed by dynamic ICG-videography. This flap did not develop postoperative complications. In conclusion, evaluation of perfusion by ICG imaging is feasible in all kinds of microsurgical flaps, irrespective of the type of tissue. Even though not meeting all the criteria of an ideal monitoring device, significant additional information can be obtained. In this study, cases with arterial spasm, venous congestion, and regional hypoperfusion were revealed by intraoperative ICG-videography. There was a strong correlation between intraoperative findings and clinical outcome. © 2002 Wiley-Liss, Inc. MICROSURGERY 22:278–287 2002
---
paper_title: Venous drainage in retrograde island flap: an experimental study using fluorescence tracing technique.

paper_content:

The pathway of venous drainage in retrograde island flaps was investigated by fluorescence tracing technique using the saphenous fasciocutaneous flap in New Zealand White rabbits. Forty animals were allocated into four groups according to the different times at 30 minutes (I), 24 hours (II), 72 hours (III), and 7 days (IV) after the operation. According to the different routes to give tracer, each group was further allocated into two subgroups of the artery injection and vein injection. For each animal, one hindlimb was assigned as the experimental side, the contralateral side as control without giving tracer. The erythrocytes were separated, labeled with fluorescein isothiocyanate (FITC), detected, and injected into the artery or vein. Subsequently, the flaps were harvested 5 seconds after injection and immediately frozen, sectioned, and observed under microscope. In group I and II, the fluorescence was observed mainly around the vessel adventitia of the vein and artery and tunica intima of the artery. In group III, there was weak fluorescence observed in the lumen of vein. In group IV, fluorescence was distributed principally in the lumen of the vein. In addition, fluorescence was not observed in the saphenous nerve in group I and there was mild fluorescence in the saphenous nerve in groups II, III, and IV. These findings suggest that the venous return is through "bypass route" in earlier period. In later period, the venous retrograde return is through "bypass route" and "incompetent valves route;" however, "incompetent valves route" becomes the main route.
---
paper_title: Intraoperative assessment of kidney allograft perfusion by laser-assisted indocyanine green fluorescence videography.

paper_content:

BACKGROUND ::: Kidney allograft function crucially depends on the quality of organ perfusion. Duplex sonography, however, frequently reveals hypoperfused segments that remained undetectable to visual inspection intraoperatively. To date, no imaging system supplementing the surgeon's experience has achieved clinical acceptance. The present work examines whether laser-assisted indocyanine green (ICG) fluorescence-videography can be used as a safe and sensitive technique for the intraoperative assessment of renal allograft perfusion. ::: ::: ::: METHODS ::: Intraoperative assessment of organ perfusion by laser-assisted ICG fluorescence videography (IC-VIEW) was performed in 10 consecutive de novo renal transplantations. The IC-VIEW system allows the visualization of graft perfusion by the fluorescein dye ICG that emits infrared light after exposure to laser light. ::: ::: ::: RESULTS ::: Perfusion measurements were successful in all 10 transplant recipients. Fluorescence videography produced brilliant, sharply contrasted images of the organs, allowing the detection of even small perfusion deficits. Remarkably, this technique detected 1 large perfusion defect that had remained imperceptible to visual inspection. Repositioning of the graft led to a homogeneous overall perfusion. There were no complications with the ICG injection or the imaging device. ::: ::: ::: CONCLUSION ::: Laser-assisted ICG fluorescence videography is a feasible and safe technique for the intraoperative assessment of renal allograft perfusion.
---
paper_title: Predictive capability of near-infrared fluorescence angiography in submental perforator flap survival.

paper_content:

BACKGROUND ::: Perforator flaps have become increasingly popular in reconstructive surgery, as patients experience less donor-site morbidity than with conventional musculocutaneous flaps. Previously, the authors' laboratory described the intraoperative use of near-infrared fluorescence angiography for patient-specific perforator flap design. This study evaluates the predictive capability of near-infrared fluorescence angiography for flap survival in submental flap reconstruction. ::: ::: ::: METHODS ::: Near-infrared angiography was performed using indocyanine green at 0, 0.5, 24, 48, and 72 hours after surgery for flap creation in 12 pigs. A single perforator artery was preserved during flap creation based on location (central or noncentral) and dominance (dominant or nondominant). Venous drainage, arterial perfusion, and perfused area as a percentage of total flap area were analyzed. Clinical assessments of perfusion were compared with those made using near-infrared imaging and histology. ::: ::: ::: RESULTS ::: Use of near-infrared fluorescence angiography immediately after flap creation accurately predicted areas of perfusion at 72 hours (p=0.0013), compared with the initial clinical assessment (p=0.3085). Identification of necrosis by histology at 72 hours correlated with near-infrared findings of insufficient arterial perfusion immediately after flap creation. No statistically significant differences in perfusion metrics were detected based on location or dominance of the preserved perforator; however, flaps containing central perforators had a higher percentage perfused area than those with noncentral perforators. ::: ::: ::: CONCLUSIONS ::: The use of near-infrared angiography immediately after flap creation can predict areas of perfusion at 72 hours. This predictive capability may permit intraoperative revision of compromised flaps that have a high likelihood of failure.
---
paper_title: Evaluation of the vascular integrity of free flaps based on microcirculation imaging techniques.

paper_content:

BACKGROUND ::: A free-flap graft refers to the free transfer of tissue to cover tissue defects caused by trauma or malperfusion in plastic surgery. The basic principle, which makes a free flap working is an adequate blood flow. We applied new techniques which are able to detect the blood flow of the anastomosis and of dermal and subdermal tissue layers in a reliable way. ::: ::: ::: METHODS ::: To this end we applied innovative Ultrasound-techniques (contrast enhanced high resolution Ultrasound (US), color coded Doppler sonography (CCDS), Cross Beamtrade mark, Power Doppler, Tissue Harmonic Imagingtrade mark (THI), Speckle Reduction Imagingtrade mark (SRI)), as well as the Indocyanine Green (ICG) fluorescence angiography to evaluate the vascular integrity of 15 parascapular flaps implanted to the fore foot over a period of four years. The age of the subjects ranged from 16 to 60 years. The US machine (GE Logiq 9) was equipped with a Logiq 9L transducer (6-9 MHz) and the modalities of CHI (Contrast Harmonic Imaging) and True Agent Detection (dual view of B-Mode and contrast mode). ::: ::: ::: RESULTS ::: The borders of the investigated flaps could be best detected using Cross Beamtrade mark Technology with SRItrade mark and THItrade mark. Power Doppler was able to detect anastomotic vessels even if they were twisted or elongated. Reduced perfusion curves were seen in cases with low anastomotic flow in CCDS. The CHItrade mark allowed dynamic flow detection of the microcirculation of the tissue graft over a depth of up to 3 cm including quantitative perfusion curves of tissue microcirculation by using TICtrade mark analysis. There is a strong correlation between the perfusion indices measured by ICG fluorescence angiography and CHItrade mark. Furthermore the ICG showed a remarkable enhancement of fluorescence in the flap borders, which need to be explored in future investigations. ::: ::: ::: CONCLUSION ::: These new applications provide useful and effective methods for improved postoperative monitoring of free flaps in plastic surgery and can lead to substantial reduction in the overall risk of flap failure.
---
paper_title: [Increasing the reliability of SIEA flap using peroperative fluorescent angiography with indocyanine green in breast reconstruction].

paper_content:

UNLABELLED ::: The lower abdominal skin and fat have become a standard for breast reconstruction. For 30 years, techniques have evolved, seeking to reduce the morbidity while increasing the reliability of the flap. The Superficial Inferior Epigastric flap Artery (SIEA) spares the abdominal fascia and provides a very satisfying autologous breast reconstruction. However, the pedicle of this flap and its angiosome exhibit a considerable variability, making its use less reliable than other abdominal flaps. ::: ::: ::: MATERIAL ::: The Indocyanine green (ICG) is soluble dye. When illuminated by an near-infrared light, the ICG emits fluorescence that is not trapped by the skin. A single device (Photo Dynamic Eye(®)) provides the emission of the near-infrared light and the reception of the fluorescence. It provides therefore a simple and efficient intraoperative real-time surface angiographic imaging. SURGICAL PROTOCOL: After dissecting the superficial inferior epigastric vessels, the abdominal flap was harvested from the abdominal wall preserving one perforator arising from the deep inferior epigastric vessels. The perforator was then clamped, and the vascular territory of the SEIA artery was visualized using laser-induced fluorescence of the indocyanine green. The surgical technique was modified depending on the indication for surgery and the result of perfusion measurements. ::: ::: ::: RESULTS ::: The authors present four clinical cases of breast reconstruction with SIEA to illustrate this procedure. ::: ::: ::: CONCLUSION ::: The SIEA flap is another surgical technique to achieve autologous breast reconstruction without abdominal morbidity or muscular dissection. Intraoperative angiographic imaging with ICG makes this flap more reliable.
---
paper_title: Contrast harmonic ultrasound and indocyanine-green fluorescence video angiography for evaluation of dermal and subdermal microcirculation in free parascapular flaps.

paper_content:

PURPOSE ::: Contrast harmonic ultrasound (CHI) with a linear transducer is a new diagnostic approach that allows dynamic and quantitative flow detection of tissue perfusion in microsurgery. The aim of the study was the evaluation of perfusion of the dermal and subdermal layers of microvascular tissue transplants with CHI in comparison to ICG-fluorescence angiography. ::: ::: ::: MATERIAL AND METHOD ::: In a prospective clinical study Indocyanine-Green Fluorescence Video Angiography and Contrast Enhanced High Resolution Ultrasound (5-10 MHz; linear transducer; Logiq 9; GE) were used for evaluation of the microcirculation in 10 transplanted free parascapular flaps. Two regions were analysed, the centre of the flap and the region of the anastomosis. The perfusion patterns of both methods were compared. ::: ::: ::: RESULTS ::: The perfusion indexes measured by ICG-fluorescence angiography correlated very precisely in all patients with the quantitative perfusion curves of contrast-enhanced US with CHI. Two flaps with slow filling and low dye intensity showed low contrast enhancement in CHI with modified perfusion curves with slow increase. In two cases a reduced perfusion and filling were found. There were no statistical differences between the two diagnostic methods (p>0.01). ::: ::: ::: CONCLUSION ::: CHI improves US detections of dermal and subdermal microcirculation in comparison to ICG fluorescence angiography. CHI is a new diagnostic method for postoperative monitoring of free flaps.
---
paper_title: Sensitivity and specificity of ICG angiography in free flap reexploration.

paper_content:

Microscope-integrated indocyanine green near-infrared videoangiography (ICGA) is a new imaging technique to assess vascular flow through diminutive vessels used in microvascular surgery. The purpose of this investigation was to evaluate the diagnostic accuracy of ICGA in detecting microvascular thrombosis in reexploration surgery. Patients undergoing emergent reexploration surgery after free tissue transfer were enrolled in this clinical study. After the patients had been returned to the operating room the pedicle vessels were exposed and a microangiography was performed. Independent of the result, the anastomoses were opened and surgically explored. Sensitivity and specificity was calculated, using the result of exploration surgery as a reference standard. Of 200 free flaps 20 (10%) underwent reexploration surgery. The most common surgical finding was microvascular thrombosis (55%). In one case vascular compromise was due to confusion of artery and vein with anastomosis of two veins. In 40% of patients an intact vascular pedicle was found. The sensitivity and specificity of ICGA to detect microvascular thrombosis was 100% and 86%, respectively. ICGA provides an excellent diagnostic accuracy for detecting microvascular thrombosis in reexploration surgery. Routine implementation of this technique may expedite a correct diagnosis and facilitate the surgical approach by preventing unnecessary surgical manipulation of intact anastomoses.
---
paper_title: Intraoperative perfusion mapping with laser-assisted indocyanine green imaging can predict and prevent complications in immediate breast reconstruction.

paper_content:

Background:Immediate breast reconstruction results in a superior cosmetic outcome. However, immediate breast reconstruction using both prosthetic and autologous techniques is associated with significantly higher complication rates than delayed procedures. These early postoperative complications are
---
paper_title: Evaluation of skin perfusion by use of indocyanine green video angiography: Rational design and planning of trauma surgery.

paper_content:

Background:A very important aspect in the treatment of traumatic injuries is to determine the extent of skin involvement. Traditionally, this has involved clinical examinations, a more or less subjective technique. Therefore, various techniques, supplementing the clinical diagnosis, have been sugges
---
paper_title: New perfusion imaging of tissue transplants with Contrast Harmonic Ultrasound Imaging (CHI) and Magnetic Resonance Imaging (MRI) in comparison with laser-induced Indocyanine Green (ICG) fluorescence angiography

paper_content:

Purpose: Evaluation of post-surgery tissue perfusion of free flaps of the lower leg with contrast enhanced harmonic imaging (CHI), laser-induced indocyanine green (ICG) fluorescence angiography and magnetic resonance imaging (MRI). Materials and methods: 10 patients with free flaps of the lower limb were evaluated with CHI, ICG-fluorescence angiography and perfusion weighted MRI. Perfusion weighted MRI was performed after intravenous bolus injection of 25 ml Gd-DTPA. The ICG fluorescence was detected by a near-infrared-laser device (λ em = 780 nm). Ultrasound was carried out by an experienced examiner with a linear probe after intravenous bolus injection of 2.4 ml SonoVue ® . For MRI time intensity curves as well as color-coded blood volume maps of the whole free flap were qualitatively evaluated. For CHI and ICG time intensity curves in selected regions of interest were analyzed. A score from 1-5(1 = low, 5 = excellent) was used for analysis of perfusion images by three independent readers. Results: In 3 cases (radialis, parascapular and lateral thigh flap) CHI, MRI and ICG perfusion imaging showed an excellent (score 4-5) contrast enhancement of the cutaneous and subcutaneous part of the free flaps. In 2 cases of osteocutaneous flaps perfusion in central and distal parts of the free flaps was reduced (score 2). Correlation between CHI, MRI and ICG was 0.69-0.83 for the distal parts of the free flaps and 0.74-0.87 for the center of the flaps (Spearman test). Perfusion in the center of the free flaps was significantly different for MRI and ICG and also for MRI and CHI (p < 0.05, Wilcoxon test). Conclusion: These first results introduce CHI and MRI perfusion imaging as a promising post-surgery monitoring in patients with free flaps.
---
paper_title: Intraoperative near-infrared fluorescence imaging in perforator flap reconstruction: current research and early clinical experience.

paper_content:

Despite recent advances in perforator flap reconstruction, there can be significant variability in vessel size and location. Although pre-operative evaluation may provide valuable information, real-time intraoperative methods have the potential to provide the greatest benefit. Our laboratory has developed the Fluorescence-Assisted Resection and Exploration (FLARE™) near-infrared (NIR) fluorescence imaging system for visualizing, intraoperatively, details of the underlying vasculature. The FLARE™ system uses indocyanine green, a safe and reliable NIR fluorophore already FDA-approved for other indications. The system has been optimized in large animal models for the identification of perforator size, location, and perfusion, and has also been translated to the clinic for use during breast reconstruction after mastectomy. In this paper, we review our pre-clinical and clinical data, as well as literature describing the use of similar NIR fluorescence imaging systems in plastic and reconstructive surgery.
---
paper_title: Indocyanine-green fluorescence video angiography used clinically to evaluate tissue perfusion in microsurgery.

paper_content:

BACKGROUND ::: Laser-induced fluorescence angiography with indocyanine-green (ICG-FA) is a new diagnostic approach that allows quantitative evaluation of tissue perfusion in microsurgery as well as an analysis of the uptake, distribution, and clearance of dye-marked blood. ::: ::: ::: METHODS ::: The ICG-FA technique was evaluated for its sensitivity and prognostic value in comparison with clinical parameters (turgor, temperature, reperfusion time, bleeding after puncture) during and after different surgical procedures. Altogether, 91 measurements were made in cases of microvascular repair (n = 43) and free-flap surgery (n = 48). ::: ::: ::: RESULTS ::: Because of discrepancies between ICG-FA results and clinical findings, the planned postoperative management was changed 43 times (47.2%). In cases of microvascular repair that subsequently resulted in tissue necrosis, ICG fluorescence had a significantly higher prognostic value than any of the clinical parameters (p = 0.03). During free-flap surgery, intraoperative ICG-FA had better sensitivity for flap loss than clinical parameters, but postoperative ICG-FA did not. ::: ::: ::: CONCLUSIONS ::: Fluorescence angiography with ICG is a sensitive diagnostic tool for detecting compromised tissue perfusion in trauma surgery and microsurgery. Its use may improve perioperative management and thereby lead to better clinical results.
---
paper_title: Early Postoperative Detection of Tissue Necrosis in Amputation Stumps With Indocyanine Green Fluorescence Angiography

paper_content:

OBJECTIVE: Amputations of the lower extremity due to irreversible ischemic tissue loss are performed as distally as possible. Therefore, oftentimes wound-healing disorders develop, requiring additional surgical treatment. METHODS: The amputations stumps of 10 patients with irreversible ischemic tissue loss due to arteriosclerosis were investigated within 72 hours postoperatively with indocyanine green (ICG) fluorescence. RESULTS: For 6 of the investigated stumps, no perfusion deficit could be seen through fluorescence angiography. All stumps displayed primary healing. In the fluorescence angiography of 3 amputations, stump perfusions deficits predicted later tissue necrosis and had to be amputated again in a second operation. One amputation wound showed a small ICG perfusion deficit that represented a blood clot. CONCLUSION: Indocyanine green fluorescence angiography allows a perfusion analysis of amputation stumps and therefore a prediction of the expected tissue necrosis. This tool may allow reliable prediction of amputation level.
---
paper_title: Interindividual variability of the SIEA Angiosome: effects on operative strategies in breast reconstruction.

paper_content:

Background: The vascular territory of the superficial inferior epigastric artery (SIEA) remains to be clarified. The SIEA flap has traditionally been classified as a hemiabdominal flap, but recent evidence points to the fact that a sizable superficial artery is capable of supplying the entire abdominal ellipse. Methods: Twenty-five patients who met the anatomical criteria for undergoing SIEA flap surgery were studied. The abdominal flap was raised on a superficial inferior epigastric pedicle; the dominant musculocutaneous perforators were preserved and clamped above the abdominal fascia on either side. The vascular territory of the superficial epigastric artery and the contribution of the deep epigastric system were visualized using laser-induced fluorescence ofindocyanine green. The surgical technique was modified (SIEA, deep inferior epigastric perforator, or bipedicle) based on perfusion measurements and the indication for surgery. Results: The SIEA vascular territory did not cross the midline in 16 patients (64 percent), and ranged from 0 percent (two patients) to the entire abdominal ellipse (five cases). Fourteen patients (56 percent) were operated on with a unipedicle SIEA flap, five patients (20 percent) were operated on with a bipedicle flap, and in six (24 percent), a conventional deep inferior epigastric perforator flap was used. As a SIEA flap was originally intended in all patients, intraoperative perfusion measurements changed the surgical plan in 11 patients (44 percent). Conclusions: The SIEA angiosome is variable and ranges from 0 to 100 percent of the lower abdominal flap. Intraoperative perfusion measurements are indispensable for evaluating the sufficiency of this pedicle for tissue transfer, especially if the contralateral flap zones are needed for reconstruction.
---
paper_title: Detection of rheumatoid arthritis by evaluation of normalized variances of fluorescence time correlation functions.

paper_content:

Fluorescence imaging using the dye indocyanine green as a contrast agent was investigated in a prospective clinical study for the detection of rheumatoid arthritis. Normalized variances of correlated time series of fluorescence intensities describing the bolus kinetics of the contrast agent in certain regions of interest were analyzed to differentiate healthy from inflamed finger joints. These values are determined using a robust, parameter-free algorithm. We found that the normalized variance of correlation functions improves the differentiation between healthy joints of volunteers and joints with rheumatoid arthritis of patients by about 10% compared to, e.g., ratios of areas under the curves of raw data.
---
paper_title: Characterization of skin tissue soldering using diode laser and indocyanine green: in vitro studies

paper_content:

Laser tissue soldering based on protein as biological glues and other compounds can provide greater bond strength and less collateral damage. Endogenous and exogenous materials such as indocyanine green (ICG) are often added to solders to enhance light absorption. The purpose of this in vitro study was to examine the impact of different parameters of laser soldering on the thermo-physical properties of the skin. A mixture of albumin solder and ICG was prepared, and then the coated samples were irradiated by an 810 nm diode laser under different conditions. The temperature rise, number of scans (N(s)), and scan velocity (V(s)) were investigated in this study. The results showed that, at each laser irradiance (I), the tensile strength (sigma) of incisions repaired in static mode was higher than in dynamic mode and that the sigma increased with both increasing N(s) and increasing I. It is therefore important to consider the trade off between scan velocity and surface temperature for achieving an optimum operating condition.
---
paper_title: Lethal photosensitization of wound-associated microbes using indocyanine green and near-infrared light

paper_content:

BackgroundThe increase in resistance to antibiotics among disease-causing bacteria necessitates the development of alternative antimicrobial approaches such as the use of light-activated antimicrobial agents (LAAAs). Light of an appropriate wavelength activates the LAAA to produce cytotoxic species which can then cause bacterial cell death via loss of membrane integrity, lipid peroxidation, the inactivation of essential enzymes, and/or exertion of mutagenic effects due to DNA modification. In this study, the effect of the LAAA indocyanine green excited with high or low intensity light (808 nm) from a near-infrared laser (NIR) on the viability of Staphylococcus aureus, Streptococcus pyogenes and Pseudomonas aeruginosa was investigated.ResultsAll species were susceptible to killing by the LAAA, the bactericidal effect being dependent on both the concentration of indocyanine green and the light dose. Indocyanine green photosensitization using both high (1.37 W cm-2) and low (0.048 W cm-2) intensity NIR laser light was able to achieve reductions of 5.6 log10 (>99.99%) and 6.8 log10 (>99.99%) in the viable counts of Staph. aureus and Strep. pyogenes (using starting concentrations of 106–107 CFU ml-1). Kills of 99.99% were obtained for P. aeruginosa (initial concentration 108–109 CFU ml-1) photosensitized by the high intensity light (1.37 W cm-2); while a kill of 80% was achieved using low intensity irradiation (0.07 W cm-2). The effects of L-tryptophan (a singlet oxygen scavenger) and deuterium oxide (as an enhancer of the life span of singlet oxygen) on the survival of Staph. aureus was also studied. L-tryptophan reduced the proportion of Staph. aureus killed; whereas deuterium oxide increased the proportion killed suggesting that singlet oxygen was involved in the killing of the bacteria.ConclusionThese findings imply that indocyanine green in combination with light from a near-infrared laser may be an effective means of eradicating bacteria from wounds and burns.
---
paper_title: A preliminary study of laser tissue soldering as arterial wall reinforcement in an acute experimental aneurysm model.

paper_content:

BACKGROUND AND OBJECTIVES ::: Aneurysm formation results from destruction of structural arterial wall connective tissue, leading to wall weakening and rupture. The purpose of this study was to demonstrate that reinforcement of the arterial wall using laser tissue soldering contributes to arterial wall stabilization and rupture prevention in an acute experimental model. ::: ::: ::: STUDY DESIGN/MATERIALS AND METHODS ::: Elastase (10 U/mg protein, Sigma-Aldrich Co., St. Louis, MO) was applied with a fine paint brush on femoral artery segments to cause fusiform aneurysm formation. After aneurysms formed (approximately 45 minutes after treatment), elastase was rinsed out and indocyanine green (ICG) and albumin soldering mixture (2.5 mg/ml ICG in 50% albumin) was delivered to the arterial segment, followed by laser irradiation at 830 nm, (15mW output for 20 minutes). In situ pressure burst measurements were then performed. ::: ::: ::: RESULTS ::: In situ burst pressures were > 503 mmHg for normal arteries and 181 +/- 26.0 mmHg, for Elastase treated segments. (P < 0.0001) Treatment of experimental aneurysms laser tissue soldering returned burst strengths to > 503 mmHg. ::: ::: ::: CONCLUSIONS ::: These results indicate laser tissue soldering reinforcement of weak arterial walls, is possible and may reduce the likelihood of acute rupture. Further development of this technique for aneurysm management is warranted.
---
paper_title: Laser welding of biomaterials stained with indocyanine green to tissues

paper_content:

This paper considers some issues pertinent to laser welding of elastin-based biomaterials to tissues using a pulsed diode laser (lO-is pulse) and indocyanine green (ICG) as an absorbing chromophore to localize laser heating to the "weld surface", the elastin/tissue interface where welding occurs. Experiments involved laser welding of elastin heterographs to the intimal surface of the carotid artery (in vitro, porcine) as a '-4x5 spotweld, then determining the breaking strength when the two tissues were pulled in a direction parallel to the plane of the spot weld while submerged in water. The questions answered are: . WHAT IS THE PEAK TEMPERATURE REQUIRED FOR WELDING ELASTIN HETEROGRAPH TO THE INTIMAL SURFACE OF CAROTID ARTERY? ANSWER: 3OO °C threshold, -6OO °C for maximum strength. This estimate is based on optical measurements of dye accumulation in stain layer and measurements of thickness of stain layer via fluorescence microscope examination. . WHATIS THE DEPENDENCE OF WELD STRENGTH ON THE LASER EXPOSURE? ANSWER: Breaking force (g) = Max*(1 exp(-(E Eth)/U67)), where Max is the maximum strength achievable by laser welding, expressed as the breaking force in g when elastin heterograph and tissue are pulled. E is the laser pulse energy. Eth is the apparent threshold laser pulse energy that will break the weld. Uth is the laser energy above threshold which achieves 67% of Max. Max was about 15 g for the -2O --2weld area of our experiments. Eth was 0.8 J. U67 was 1 .44 J. . DOES WELD STRENGTH DEPEND ON HYDRATION CONDITIONS? ANSWER: Not on the amount of excess unbound water. There was no significant difference in weld strength between welding dripping wet tissues vs well blotted tissues. S WHAT DIFFERENCE IS THERE BETWEEN IRRADIATING THE WELD SURFACE THROUGH THE BIOMATERIAL VS THROUGH THE TISSUE, WHEN THE BIOMATERIAL IS PARTIALLY STAINED WITH ICG? ANSWER: There is a difference if the stain layer is heavily stained. Irradiation through the tissue allows direct irradiation on the weld surface which achieves the highest peak temperatures for the least laser pulse energy. Irradiation through the elastin heterograph causes direct irradiation of the rear surface of the stain layer, within the biomaterial and away from the weld surface, and thermal diffusion must bring the heat to the weld surface. This difference occurs only when the absorption by the stain layer is sufficiently high that little laser energy directly reaches the weld surface.
---
paper_title: Biodistribution of indocyanine green in a porcine burn model: light and fluorescence microscopy.

paper_content:

BACKGROUND ::: Infrared-excited fluorescence of intravenously administered indocyanine green (ICG) is being used as a method of early determination of burn depth. ::: ::: ::: METHODS ::: Fluorescence microscopy and tissue fluorescence were recorded in a porcine burn model and correlated to burn severity and age. ::: ::: ::: RESULTS ::: Recently placed superficial burns show significant fluorescence compared with adjacent normal tissue as a result of a strong inflammatory reaction in the superficial dermis with minimal vascular occlusion. The magnitude of the inflammatory reaction decreases with time. For deeper burns, vascular occlusion prevents transport of ICG into the burn and the intensity of ICG fluorescence in burn eschar is negligible. ::: ::: ::: CONCLUSION ::: The intensity of ICG fluorescence measured at the surface of the wound for burns of similar age was shown to decrease exponentially with the depth of the burn. The enhanced fluorescence of partial-thickness burns is attributable to increased permeability, and the decreased signal associated with deeper injuries is attributable to vascular occlusion. These results suggest that it is possible to differentiate burns that will heal spontaneously with minimal granulation from those that will not by measuring the intensity of ICG fluorescence.
---
paper_title: Sutureless laparoscopic heminephrectomy using laser tissue soldering.

paper_content:

BACKGROUND AND PURPOSE ::: Widespread application of laparoscopic partial nephrectomy has been limited by the lack of a reliable means of attaining hemostasis. We describe laser tissue welding using human albumin as a solder to control bleeding and seal the collecting system during laparoscopic heminephrectomy in a porcine model. ::: ::: ::: MATERIALS AND METHODS ::: Laparoscopic left lower-pole heminephrectomy was performed in five female domestic pigs after occluding the hilar vessels. Using an 810-nm pulsed diode laser (20 W), a 50% liquid albumin-indocyanine green solder was welded to the cut edge of the renal parenchyma to seal the collecting system and achieve hemostasis. Two weeks later, an identical procedure was performed on the right kidney, after which, the animals were sacrificed and both kidneys were harvested for ex vivo retrograde pyelograms and histopathologic analysis. ::: ::: ::: RESULTS ::: All 10 heminephrectomies were performed without complication. The mean operative time was 82 minutes, with an average blood loss of 43.5 mL per procedure. The mean warm ischemia time was 11.7 minutes. For each heminephrectomy, a mean of 4.2 mL of solder was welded to the cut parenchymal surface. In three of the five acute kidneys and all five 2-week kidneys, ex vivo retrograde pyelograms demonstrated no extravasation. In addition, no animal had clinical evidence of urinoma or delayed hemorrhage. Histopathologic analysis showed preservation of the renal parenchyma immediately beneath the solder. ::: ::: ::: DISCUSSION ::: Laser tissue welding provided reliable hemostasis and closure of the collecting system while protecting the underlying parenchyma from the deleterious effect of the laser during porcine laparoscopic heminephrectomy.
---
paper_title: In vivo optical imaging in arthritis—an enlightening future?

paper_content:

In vivo molecular optical imaging has significant potential to delineate and measure, at the macroscopic level, in vivo biological processes that are occurring at the cellular and molecular level. Optical imaging has already been developed for in vitro and ex vivo applications in molecular and cellular biology (e.g. fluorescence confocal microscopy), but is still at an early stage of development as a whole-animal in vivo imaging technique. Both sensitivity and spatial resolution remain incompletely defined. Rapid advances in hardware technology and highly innovative reporter probes and dyes will be expected to deliver significant insight into perturbations of molecular pathways that occur in disease, ultimately with the potential of translating into future molecular imaging techniques for patients with arthritis. This review will focus on currently available technologies for live in vivo animal optical imaging, including fluorescence reflectance imaging, potential novel tomographic techniques, bioluminescence reporter technology and potential novel labelling techniques, highlighting in particular the potential application of in vivo fluorescence imaging in arthritis.
---
paper_title: Thermal and molecular investigation of laser tissue welding

paper_content:

Despite the growing number of successful animal and human trials, the exact mechanisms of laser tissue welding remain unknown. Furthermore, the effects of laser heating on tissue on the molecular scale are not fully understood. To address these issues, a multi-front attack oil both extrinsic (solder/patch mediated) and intrinsic (laser only) tissue welding was launched using two-color infrared thermometry, computer modeling, weld strength assessment, biochemical assays, and vibrational spectroscopy. The coupling of experimentally measured surface temperatures with the predictive numerical simulations provided insight into the sub-surface dynamics of the laser tissue welding process. Quantification of the acute strength of the welds following the welding procedure enabled comparison among trials during an experiment, with previous experiments, and with other studies in the literature. The acute weld integrity also provided an indication of tile probability of long-term success. Molecular effects induced In the tissue by laser irradiation were investigated by measuring tile concentrations of specific collagen covalent crosslinks and characterizing the Fourier-Transform infrared (FTIR) spectra before and after the laser exposure.
---
paper_title: Sutureless sealing of penetrating corneal wounds using a laser-activated thin film adhesive

paper_content:

BACKGROUND AND OBJECTIVES ::: To demonstrate the feasibility of a novel, thin film, laser-activated adhesive in sealing penetrative corneal wounds with a view to replacing sutures in ophthalmic operations. ::: ::: ::: METHODS ::: A previously described thin film adhesive composed of chitosan and indocyanine green activated by infrared laser (808 nm) was used to seal penetrating corneal wounds ranging from 1 to 6 mm in size in enucleated bovine eyes. The excised corneas were subjected to pressure tests to evaluate the strength of the corneal repairs and compared to sutures and commercial fibrin glue, Tisseel®. Temperatures at the adhesive-tissue interface were measured and histological examinations of the repairs performed to investigate potential tissue damage. Biodegradability of the films was monitored in lysozyme solutions at concentrations reported in tears. ::: ::: ::: RESULTS ::: The adhesive effectively sealed corneal wounds, withstanding pressures of 140-320 mmHg, far in excess of the normal intraocular pressure. In contrast, pressures of 40-80 mm Hg were determined using a combination of sutures with Tisseel® as a sealant. The laser-activation process was 1.5-5 times faster than other procedures studied and required no curing time. A transient, mean temperature of 56 ± 2°C was measured at the adhesive-tissue interface while histology showed no tissue damage as a consequence of the irradiation process. Irradiation had no significant influence on adhesive biodegradation in vitro, which lost approximately 30% of their initial weight in a lysozyme solution (6 mg ml(-1)). ::: ::: ::: CONCLUSIONS ::: The thin film adhesive was found to be an effective in sealing corneal wounds with considerable advantages over sutures, including speed of application and sealing strength and biodegradability.
---
paper_title: Detection of rheumatoid arthritis using non-specific contrast enhanced fluorescence imaging.

paper_content:

RATIONALE AND OBJECTIVES ::: The aim of this study was to develop a new tool for the early detection of inflammatory joint diseases using fluorescence imaging in the near-infrared (NIR) spectral range following the intravenous administration of an unspecific contrast agent. ::: ::: ::: MATERIALS AND METHODS ::: A laser-supported system for fluorescence imaging of finger joints was designed and constructed. Five patients and a corresponding number of volunteers were examined using 0.1 mg/kg by weight of indocyanine green as an unspecific contrast agent. Fluorescence images were acquired continuously over a period of 15 minutes. As a control, 1 day before optical imaging, all patients and volunteers underwent contrast-enhanced magnetic resonance imaging (MRI) at 0.2 T. On the basis of MRI findings, all examined joints were divided into four groups: no change and mild, moderate, and severe synovitis. The emitted fluorescence photons were quantified in different regions of interest covering the finger joints and finger tips. The normalized fluorescence intensity of contrast agents was compared with MRI findings as a proven standard. ::: ::: ::: RESULTS ::: NIR dyes of the cyanine class are enriched in inflammatory joints and show a different kinetic behavior compared to normal joints after bolus injection. These findings demonstrate clearly the capability of contrast-enhanced fluorescence imaging to detect early changes caused by rheumatoid arthritis in finger joints. The NIR results were correlated with MRI findings (r = 0.84). ::: ::: ::: CONCLUSION ::: Contrast-enhanced fluorescence imaging provides adequate information for the evaluation of inflammatory involvement of finger joints comparable to low-field MRI.
---
paper_title: Theoretical investigation of measuring cerebral blood flow in the adult human head using bolus Indocyanine Green injection and near-infrared spectroscopy

paper_content:

To investigate the accuracy of measuring cerebral blood flow (CBF) using a bolus injection of Indocyanine Green (ICG) detected by near-infrared spectroscopy in adult human heads, simulations were performed using a two-layered model representing the extracerebral and intracerebral layers. Modeled optical data were converted into tissue ICG concentration using either the one-detector modified Beer-Lambert law (MBLL) method, or the two-detector partial path-length (PPL) method. The CBFs were estimated using deconvolution and blood flow index techniques. Using the MBLL method, the CBFs were significantly underestimated but the PPL method improved their accuracy and robustness, especially when used as relative measures. The dispersion of the arterial input function also affected the CBF estimates.
---
paper_title: In vivo comparison of near infrared lasers for skin welding

paper_content:

The skin closure abilities of near infrared lasers and suturing were compared by histological examination and mechanical tensile tests during a 21-day healing period. One-centimeter incisions on the dorsal skin of Wistar rats were treated by one of the closing techniques: (a) soldering, using an 809 nm diode laser (0.5 W, 5 s) with 25% bovine serum albumin (BSA) and 2.5 mg/ml indocyanine green (ICG); (b) direct welding with a 980 nm diode laser (0.5 W, 5 s); (c) direct welding with a 1,070 nm fiber laser (0.5 W, 5 s); (d) suturing. Six spots (79.61 J/cm2 for each spot) were applied through the incisions. Healing was inspected on the 1st, 4th, 7th, 14th, and 21st post-operative days. The closure index (CI), thermally altered area (TAA), granulation area (GA) and epidermal thickness (ET) were determined by histological examination. Tensile tests were performed at a 5 mm/min crosshead speed up to the first opening along the incision. Immediate superficial closure with high CI values was found for the laser-irradiated incisions at the early phase of recovery. Clear welds without thermal damage were observed for the group irradiated at 1,070 nm. For the sutured group, the incisions remained unclosed for the first day, and openings through the incision were observed. At the end of the 21-day recovery period, no differences between experimental groups were observed in terms of the CI, GA and ET values. However, the tensile strength of the groups irradiated at 980 nm and 1,070 nm was found to be higher than that of the sutured incisions. The laser welding techniques were found to be reliable in terms of immediate and mechanically strong closure compared with suturing. Of them, 1,070 nm laser welding yielded noticeably stronger bonds, with minimal scarring at the end of the 21-days of recovery.
---
paper_title: Near-infrared spectroscopy and indocyanine green derived blood flow index for noninvasive measurement of muscle perfusion during exercise

paper_content:

Near-infrared spectroscopy (NIRS) with the tracer indocyanine green (ICG) may be used for measuring muscle blood flow (MBF) during exercise, if arterial ICG concentration is measured simultaneously. Although pulse dye densitometry allows for noninvasive measurement of arterial dye concentration, this technique is sensitive to motion and may not be applicable during exercise. The aim of this study was to evaluate a noninvasive blood flow index (BFI), which is derived solely from the muscle ICG concentration curve. In 10 male cyclists 5 mg ICG were injected into an antecubital vein at rest and during cycling at 30, 60, 70, 80, 90, and 100% of previously determined maximal work load. Simultaneously blood was withdrawn through a photodensitometer at 20 ml/min from the radial artery to measure arterial ICG concentration. To measure muscle tissue ICG concentrations, two sets of NIRS optodes were positioned on the skin, one over the left seventh intercostal space and the other over the left vastus lateralis muscle. MBF was calculated from the arterial and muscle concentration data according to Fick's principle. BFI was calculated solely from the muscle concentration curve as ICG concentration difference divided by rise time between 10 and 90% of peak. During exercise mean BFI values changed similarly to MBF in both intercostal and quadriceps muscles and showed excellent correlations with MBF: r = 0.98 and 0.96, respectively. Individual data showed some scattering among BFI and MBF values but still reasonable correlations of BFI with MBF: r = 0.73 and 0.72 for intercostal and quadriceps muscles, respectively. Interobserver variability, as analyzed by Bland-Altman plots, was considerably less for BFI than MBF. These data suggest that BFI can be used for measuring changes in muscle perfusion from rest to maximal exercise. Although absolute blood flow cannot be determined, BFI has the advantages of being essentially noninvasive and having low interobserver variability.
---
paper_title: Noninvasive monitoring of cerebral blood flow by a dye bolus method: Separation of brain from skin and skull signals

paper_content:

Tracking a bolus of contrast agent traveling through the cerebral vasculature provides a measure of the blood flow velocity in the respective cerebral tissue. This principle has been the basis for the first approaches in functional magnetic resonance (MR) imaging and is of great value for investigating patients with vascular disease, especially stroke. While bolus measurements are a standard procedure in MR imaging, optical bolus tracking is as yet not established. Here we study optical absorption changes induced by a bolus of the dye indocyanine-green with near infrared spectroscopy in healthy volunteers. The aim is to assess the latency and shape of the change in absorption. Since application in the adult human critically depends on differentiation between extra- and intracerebral vascular compartments we focus on an approach for such a separation. To do this frequency-domain and multidistance measurements are analyzed by a Monte Carlo based model for photon transport in tissue. Based on measurements of both the photon’s mean time of flight (phase) and the intensity, our results allow differentiation between an upper (skin and skull) and a lower layer (brain). The bolus in the deeper tissue layers has a peak of about 10 s width, while the change in absorption in the upper layers shows a much longer recovery time. This is in qualitative agreement with MR imaging results using a gadolinium bolus. This result is promising with respect to the potential of bedside monitoring of mean transit time (MTT) changes in patients with stroke or related vascular disease.
---
paper_title: Optical image analysis of fat cells for indocyanine green mediated near-infrared laser treatment

paper_content:

Fat tissue engineering by near-infrared laser treatment is investigated in vitro. For the quantitative estimation of efficiency of treatment and consequential processes on the cellular level, a computational method for optical image analysis is proposed. The method is based on the fractal dimension data analysis of fat cell structure. The conducted experiments confirm the feasibility of the proposed method to obtain quantitative information of the cellular processes. The results indicate that the proposed method is promising for estimating spatial changes of biological structure.
---
paper_title: Lethal photosensitization of wound-associated microbes using indocyanine green and near-infrared light

paper_content:

BackgroundThe increase in resistance to antibiotics among disease-causing bacteria necessitates the development of alternative antimicrobial approaches such as the use of light-activated antimicrobial agents (LAAAs). Light of an appropriate wavelength activates the LAAA to produce cytotoxic species which can then cause bacterial cell death via loss of membrane integrity, lipid peroxidation, the inactivation of essential enzymes, and/or exertion of mutagenic effects due to DNA modification. In this study, the effect of the LAAA indocyanine green excited with high or low intensity light (808 nm) from a near-infrared laser (NIR) on the viability of Staphylococcus aureus, Streptococcus pyogenes and Pseudomonas aeruginosa was investigated.ResultsAll species were susceptible to killing by the LAAA, the bactericidal effect being dependent on both the concentration of indocyanine green and the light dose. Indocyanine green photosensitization using both high (1.37 W cm-2) and low (0.048 W cm-2) intensity NIR laser light was able to achieve reductions of 5.6 log10 (>99.99%) and 6.8 log10 (>99.99%) in the viable counts of Staph. aureus and Strep. pyogenes (using starting concentrations of 106–107 CFU ml-1). Kills of 99.99% were obtained for P. aeruginosa (initial concentration 108–109 CFU ml-1) photosensitized by the high intensity light (1.37 W cm-2); while a kill of 80% was achieved using low intensity irradiation (0.07 W cm-2). The effects of L-tryptophan (a singlet oxygen scavenger) and deuterium oxide (as an enhancer of the life span of singlet oxygen) on the survival of Staph. aureus was also studied. L-tryptophan reduced the proportion of Staph. aureus killed; whereas deuterium oxide increased the proportion killed suggesting that singlet oxygen was involved in the killing of the bacteria.ConclusionThese findings imply that indocyanine green in combination with light from a near-infrared laser may be an effective means of eradicating bacteria from wounds and burns.
---
paper_title: Topical ALA-photodynamic therapy for the treatment of acne vulgaris.

paper_content:

Topical aminolevulinic acid is converted into a potent photosensitizer, protoporphyrin, in human hair follicles and sebaceous glands. Photodynamic therapy with topical aminolevulinic acid was tested for the treatment of acne vulgaris, in an open-label prospective human study. Each of 22 subjects with acne on the back was treated in four sites with aminolevulinic acid plus red light, aminolevulinic acid alone, light alone, and untreated control. Half of the subjects were treated once; half were treated four times. Twenty percent topical aminolevulinic acid was applied with 3 h occlusion, and 150 J per cm2 broad-band light (550-700 nm) was given. Sebum excretion rate and auto-fluorescence from follicular bacteria were measured before, and 2, 3, 10, and 20 wk after, treatment. Histologic changes and protoporphyrin synthesis in pilosebaceous units were observed from skin biopsies. Aminolevulinic acid plus red light caused a transient acne-like folliculitis. Sebum excretion was eliminated for several weeks, and decreased for 20 wk after photodynamic therapy; multiple treatments caused greater suppression of sebum. Bacterial porphyrin fluorescence was also suppressed by photodynamic therapy. On histology, sebaceous glands showed acute damage and were smaller 20 wk after photodynamic therapy. There was clinical and statistically significant clearance of inflammatory acne by aminolevulinic acid plus red light, for at least 20 wk after multiple treatments and 10 wk after a single treatment. Transient hyperpigmentation, superficial exfoliation, and crusting were observed, which cleared without scarring. Topical aminolevulinic acid plus red light is an effective treatment of acne vulgaris, associated with significant side-effects. Aminolevulinic acid plus red light causes phototoxicity to sebaceous follicles, prolonged suppression of sebaceous gland function, and apparent decrease in follicular bacteria after photodynamic therapy. Potentially, aminolevulinic acid plus red light may be useful for some patients with acne.
---
paper_title: Low-intensity indocyanine-green laser phototherapy of acne vulgaris: Pilot study

paper_content:

Near infrared (NIR) diode laser low-intensity (soft) photo- therapy with the topical application of indocyanine green (ICG) has been suggested for treatment of acne vulgaris. Twelve volunteers with acne lesions on their faces and/or backs were enrolled in the experi- ment. Skin areas of the subjects that were 43 5c m 2 were stained with ICG solution for 5 min before laser irradiation (803 nm) at a power density up to 50 mW/cm 2 for 5 to 10 min. For 75% of the subjects, a single treatment was provided and for the other 25%, eight sequential treatments over a period of a month were carried out. Observations a month after the completion of the treatment showed that only the multiple treatments with a combination of ICG and NIR irradiation reduced inflammation and improved the state of the skin for a month without any side effects. A month after treatment, the improvement was about 80% for the group receiving multiple treatments. Single treatments did not have a prolonged effect. © 2004 Society of Photo-Optical
---
paper_title: A pilot study of ICG laser therapy ofacne vulgaris: Photodynamic and photothermolysis treatment

paper_content:

Background and Objectives: The near-infrared (NIR) laser radiation due to its high penetration depth is widely used in phototherapy. In application to skin appendages, a high selectivity of laser treatment is needed to prevent light action on surrounding tissues. Indocyanine green (ICG) dye may provide a high selectivity of treatment due to effective ICG uploading by a target and its narrow band of considerable absorption just at the wavelength of the NIR diode laser. The goal of this study is to demonstrate the efficacy of the NIR diode laser phototherapy in combination with topical application of ICG suggested for soft and thermal treatment of acne vulgaris.
---
paper_title: Phototherapy for chronic rhinosinusitis

paper_content:

OBJECTIVES ::: Near-infrared laser illumination (NILI), with or without photo-activated (PA) agents, has bactericidal and wound healing promoting effects. NILI may have a potential role managing chronic rhinosinusitis (CRS). ::: ::: ::: METHODS ::: A prospective randomized study with 23 symptomatic post-surgical CRS patients with positive cultures was conducted. Two groups (GR1 and GR2) were treated with NILI. Objective nasal endoscopic scoring (NES) was elaborated. GR1 was treated with a 940 nm laser, while GR2 was treated with a topical PA agent, indocyanine-green, followed with 810 nm laser. SNOT20 scores, NES, and cultures were obtained prior to illumination. Saccharin test was performed 1 week following treatment. ::: ::: ::: RESULTS ::: Some cultures remained positive through treatment, with Staph. aureus predominating. Both therapy arms demonstrated clinical efficacy. The SNOT20 score change was 0.9, 0.8 for GR1 and GR2, respectively (P < 0.05). Improvement (P < 0.05) was observed based on NES. No significant difference was observed between two treatment groups. All passed the saccharin test. Therapeutic effect was sustained for a minimum of 2 months. Side effects were minimal. ::: ::: ::: CONCLUSIONS ::: NILI was objectively and subjectively beneficial in managing CRS, safe, reproducible, sustained and appeared not to interfere with ciliary motility. CRS exacerbation was avoided without using antibiotics or steroids.
---
paper_title: Differentiation of mouse embryonic stem cells into hepatocytes induced by a combination of cytokines and sodium butyrate

paper_content:

There is increasing evidence to suggest that embryonic stem cells (ESCs) are capable of differentiating into hepatocytes in vitro. In this study, we used a combination of cytokines and sodium butyrate in a novel three-step procedure to efficiently direct the differentiation of mouse ESCs into hepatocytes. Mouse ESCs were first differentiated into definitive endoderm cells by 3 days of treatment with Activin A. The definitive endoderm cells were then differentiated into hepatocytes by the addition of acidic fibroblast growth factor (aFGF) and sodium butyrate to the culture medium for 5 days. After 10 days of further in vitro maturation, the morphological and phenotypic markers of hepatocytes were characterized using immunohistochemistry, immunoblotting, and reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, the cells were tested for functions associated with mature hepatocytes, including glycogen storage and indocyanine green uptake and release, and the ratio of hepatic differentiation was determined by counting the percentage of albumin-positive cells. In the presence of medium containing cytokines and sodium butyrate, numerous epithelial cells resembling hepatocytes were observed, and ∼74% of the cells expressed the hepatic marker, albumin, after 18 days in culture. RT-PCR analysis and immunohistochemistry showed that these cells expressed adult liver cell markers, and had the abilities of glycogen storage and indocyanine green uptake and release. We have developed an efficient method for directing the differentiation of mouse ESCs into cells that exhibit the characteristics of mature hepatocytes. This technique will be useful for research into the molecular mechanisms underlying liver development, and could provide a source of hepatocytes for transplantation therapy and drug screening.
---
paper_title: Surgical usefulness of indocyanine green as an alternative to India ink for endoscopic marking

paper_content:

BACKGROUND ::: India ink has been commonly used for preoperative colonic tattooing, but various complications have been reported. This study aimed to evaluate the usefulness of indocyanine green (ICG) marking as a replacement for India ink. ::: ::: ::: METHODS ::: This study enrolled 40 patients who between January 2005 and February 2006 underwent laparoscopic or open surgery for colorectal lesions considered difficult to locate intraoperatively. Because one patient had a history of allergy to iodinated contrast material, metal clipping was used instead of ICG to mark the lesion. Endoscopists injected 5 ml of ICG suspension and saline solution adjacent to the lesion at duplicate locations to evaluate the visibility, duration, and adverse effects of the dye. For 39 patients, the date of the preoperative colonoscopy was not set for examination of the appropriate interval between endoscopic marking and the surgical operation. ::: ::: ::: RESULTS ::: The median interval between ICG marking and surgery was 4 days (range, 1-73 days). All 29 patients who underwent surgery within 8 days after marking had positive green ICG staining at the time of surgery. After 9 days or more, however, positive staining was seen clearly in only two of the remaining 10 patients. The staining tended to grow weaker and fainter over the time course, eventually dissipating. No perioperative adverse reactions to the dye were observed. ::: ::: ::: CONCLUSION ::: This study supports the use of ICG as a safe technique that can be identified reliably during operations performed within 8 days after endoscopic injection.
---
paper_title: Mechanism of dye-enhanced pulsed laser ablation of hard tissues: implications for dentistry

paper_content:

Alexandrite laser ablation of enamel enhanced by an indocyanine green dye was studied. A microjet system was employed to deliver precisely measured small amounts of absorbing dye solution to the site of irradiation. A sequence of physical phenomena involved in dye-enhanced laser ablation of dental enamel was revealed when laser pulse profiles were compared with the profiles of laser-induced pressure, laser-induced plasma, and ablation plume kinetics. To understand photomechanical effects on the enamel ablation, the absolute values of pressure waves were measured by a calibrated wide-band acoustic transducer. Absolute amplitude and temporal profile of pressure waves, plasma emission, ablation plume kinetics, ablation efficiency, and crater quality under free-running and and Q-switched ablation of enamel were studied. It was found that there is an optimal dye solution volume (100-200 nL) when the maximum ablation efficiency (30 μm/pulse) can be obtained. It was shown that the ablation efficiency under Q-switched laser irradiation is approximately one order of magnitude lower than that under free-running ablation. It was shown that Q-switched enamel ablation with dye solution is caused by the powerful recoil pressure wave with an amplitude 3-6.5 kbar. In contrast, dye-enhanced free-running enamel ablation is caused by plasma-mediated evaporation of enamel and accompanied by recoil pressure waves of lower amplitude (0.5-1 kbar) that is below mechanical damage threshold in enamel. Uneven crater walls after Q-switched ablation were observed by scanning electron microscopy (SEM). Free-running ablation makes precise craters with smooth and even crater walls.
---
paper_title: Colonic tattooing using fluorescence imaging with light-emitting diode-activated indocyanine green: A feasibility study

paper_content:

PURPOSE ::: We investigated the feasibility of a fluorescence imaging technique using light-emitting diode (LED)-activated indocyanine green (ICG) fluorescence. ::: ::: ::: METHODS ::: Indocyanine green injections were given to patients undergoing preoperative colonoscopy for early colon cancer or colon adenoma. During subsequent laparotomy, the colon was first observed with the naked eye, and then using a prototype machine with a charge-coupled device (CCD) video camera equipped with a cutoff filter and a LED at a wavelength of 760 nm as the light source. ::: ::: ::: RESULTS ::: LED-induced fluorescence showed tumor localization clearly and accurately in all ten patients (100%) enrolled in this study, whereas it was seen with the naked eye as a green spot in only two patients (20%) (P = 0.0077; Wilcoxon's signed-rank test). There were no complications of LED-induced fluorescence and no inflammatory signs were noted on the hematoxylin-eosin-stained slides for the identified injection sites in the resected specimens. ::: ::: ::: CONCLUSIONS ::: Colonic tattooing using this fluorescence imaging technique of LED-activated ICG fluorescence is a new concept of colonic marking based on the characteristics that ICG is a near infrared fluorescent dye, and is useful, without any adverse effects, to identify perioperatively the tumor localization.
---
paper_title: In-vitro and in-vivo study of dye diffusion into the human skin and hair follicles

paper_content:

We present experimental results on in vitro and in vivo investigation of dye diffusion into the human skin and hair follicles. It was shown that dyeing as a method of enhancement of the absorption coefficient of hair follicle tissue components can be used for selective photodestruction of hair follicle and surrounding tissues. Strength and depth of hair follicle dyeing inside the skin were determined for various dyes.
---
paper_title: Indocyanine green fluorescence monitoring of perineal wound contamination in abdominoperineal resection: A preliminary report

paper_content:

PURPOSE ::: Surgical site infections (SSI) in an abdominoperineal resection (APR) occur more frequently than in other types of operations for patients with colorectal cancer. Perineal wounds are the most vulnerable sites, and they may be caused by stool contamination. Indocyanine green (ICG) fluorescence imaging, by which sensitive detection was possible, was used as a marker of perineal wound contamination. ::: ::: ::: METHOD ::: Indocyanine green was transanally injected to the rectum before operation, and fluorescence images were obtained during the operation in three patients who underwent APR. ::: ::: ::: RESULTS ::: One subject, in whom gross contamination was not visible, had an SSI, and a trace of ICG fluorescence was detectable in the perianal skin. The other two subjects, in whom skin preparation was completely performed until ICG contamination was eliminated, were free from SSI. ::: ::: ::: CONCLUSIONS ::: Our results suggested that a trace of stool contamination remained in the perineal skin field even after the usual antiseptic skin preparation. Furthermore, meticulous skin preparation is required to minimize stool contamination in APR patients.
---
paper_title: Safety and efficacy of India ink and indocyanine green as colonic tattooing agents

paper_content:

Abstract Background: Controversy exists concerning the safety and efficacy of colonic tattooing for the intraoperative identification of polypectomy sites. The purpose of this study was to determine (1) the concentrations of India ink and indocyanine green that resulted in high-visibility tattoos without significant tissue inflammation and (2) the India ink injection volume that produces best visibility at colonoscopy, laparoscopy, and laparotomy. Methods: Twenty-two New Zealand white rabbits (2 kg) were anesthetized and injected with India ink (undiluted 1:10, 1:50, 1:100, 1:1000, 1:10,000) and indocyanine green as an undiluted, concentrated formulation (25 mL/2 mL solvent) or in a diluted form (25 mg/5 mL solvent) at various concentrations (1:10, 1:50, 1:100). Tuberculin syringes were used to create a 0.1 mL serosal bleb at two injection sites 2 cm apart. Laparotomy was repeated at days 1, 3, and 7 after injection. Additionally, 16 rabbits were injected with India ink at laparotomy and re-explored at 1 and 5 months. Twelve mongrel dogs (20 kg) were injected with 1.0 mL volumes. Re-exploration by colonoscopy, laparoscopy, and laparotomy was done at 7 days and 1 month. Tattoo visibility at re-exploration in both animal models was graded on a scale (0 = agent not seen, 1=seen with difficulty, 2=easily seen). Histology in the rabbit was judged by degrees of inflammation (0 = no inflammation, 2=mild inflammation, 4=moderate inflammation, 6=severe inflammation). Results: The concentrated indocyanine green solution was easily visible only on day 1 in the rabbit. Injections of both concentrated and diluted indocyanine green caused mucosal ulceration and moderate to severe inflammation. India ink studied at 7 days, 1 month, and 5 months after injection in the rabbit model was visible at all concentrations. The undiluted and 1:10 concentrations were easily seen and showed evidence of mucosal ulceration. Tattoos produced with all other India ink concentrations were visible without gross inflammation. India ink was also studied at 7 days and 1 month in dogs. The tattoo with the 1:100 concentration at 0.5 mL was seen consistently at colonoscopy, laparoscopy, and laparotomy with only a mild submucosal reaction at 7 days. The tattoos produced with the 1:100 and 1:1000 concentrations at 0.5 mL and 1.0 mL injection volumes were easily seen by all methods of intraabdominal visualization at 1 month with similar histology. Conclusion: Indocyanine green was an ineffective colonic tattooing agent. India ink was an effective colonic tattooing agent. Dilute concentrations that caused little to no inflammation could be visualized at 7 days and 1 month in rabbits and dogs and at 5 months in rabbits. India ink, at appropriated concentrations, appears to be a safe short- and long-term colonic tattooing agent. (Gastrointest Endosc 2000;51:438-42.)
---
paper_title: Ultrasonography-guided hepatic tumor resection using a real-time virtual sonography with indocyanine green navigation (with videos)

paper_content:

PURPOSE ::: For hepatic tumors that cannot be identified on routine ultrasonography (US), we marked the target area using real-time virtual sonography (RVS) with indocyanine green (ICG)-ethanol (1:100) during surgery, and performed hepatic resection while observing the fluorescence. ::: ::: ::: EXPERIMENT ::: An ICG-ethanol mixture locally injected into mouse liver was retained in the same area for more than 4 h. The same mixture locally injected into pig liver at a depth of 3 cm could be observed using an infrared camera. ::: ::: ::: CASE ::: An ICG-ethanol mixture (500 μl) was locally injected under RVS guidance into a metastatic hepatic tumor that was visible only on magnetic resonance imaging (MRI), and hepatic resection was performed while Photodynamic Eye (PDE) images were being observed. The metastatic lesion (3 mm in diameter in a pathological specimen) could be successfully resected. ::: ::: ::: CONCLUSION ::: This method was useful for resecting US-invisible hepatic tumors.
---
paper_title: Labeling human embryonic stem cell-derived cardiomyocytes with indocyanine green for noninvasive tracking with optical imaging: an FDA-compatible alternative to firefly luciferase.

paper_content:

Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) have demonstrated the ability to improve myocardial function following transplantation into an ischemic heart; however, the functional benefits are transient possibly due to poor cell retention. A diagnostic technique that could visualize transplanted hESC-CMs could help to optimize stem cell delivery techniques. Thus, the purpose of this study was to develop a labeling technique for hESCs and hESC-CMs with the FDA-approved contrast agent indocyanine green (ICG) for optical imaging (OI). hESCs were labeled with 0.5, 1.0, 2.0, and 2.5 mg/ml of ICG for 30, 45, and 60 min at 37 degrees C. Longitudinal OI studies were performed with both hESCs and hESC-CMs. The expression of surface proteins was assessed with immunofluorescent staining. hESCs labeled with 2 mg ICG/ml for 60 min achieved maximum fluorescence. Longitudinal studies revealed that the fluorescent signal was equivalent to controls at 120 h postlabeling. The fluorescence signal of hESCs and hESC-CMs at 1, 24, and 48 h was significantly higher compared to precontrast data (p < 0.05). Immunocytochemistry revealed retention of cell-specific surface and nuclear markers postlabeling. These data demonstrate that hESCs and hESC-CMs labeled with ICG show a significant fluorescence up to 48 h and can be visualized with OI. The labeling procedure does not impair the viability or functional integrity of the cells. The technique may be useful for assessing different delivery routes in order to improve the engraftment of transplanted hESC-CMs or other stem cell progenitors.
---
paper_title: Generation of functional hepatocytes from mouse induced pluripotent stem cells.

paper_content:

Induced pluripotent stem cells are derived from somatic cells by forced expression of several transcriptional factors. Induced pluripotent stem cells resemble embryonic stem cells in many aspects, such as the expression of certain stem cell markers, chromatin methylation patterns, embryoid body formation and teratoma formation. Therefore, induced pluripotent stem cells provide a powerful tool for study of developmental biology and unlimited resources for transplantation therapy. Here we reported the successful induction of mouse induced pluripotent stem cells and a simple and efficient process for generation of functional hepatocytes from mouse induced pluripotent stem cells by sequential addition of inducing factors. These induced pluripotent stem cell-derived hepatocytes, just as mouse embryonic stem cell-derived hepatocytes, expressed hepatic lineage markers including CK7, CK8, CK18, CK19, alpha-fetoprotein, albumin, Cyp7a1, and exhibited functional hepatic characteristics, including glycogen storage, indocyanine green (ICG) uptake and release, low-density lipoprotein (LDL) uptake and urea secretion. Although we observed some variations in the efficiency of hepatic differentiation between induced pluripotent stem cells and common mouse embryonic stem cell lines, our results indicate that mouse induced pluripotent stem cells can efficiently differentiate into functional hepatocytes in vitro, which may be helpful for the study of liver development and regenerative medicine.
---
paper_title: Optical image analysis of fat cells for indocyanine green mediated near-infrared laser treatment

paper_content:

Fat tissue engineering by near-infrared laser treatment is investigated in vitro. For the quantitative estimation of efficiency of treatment and consequential processes on the cellular level, a computational method for optical image analysis is proposed. The method is based on the fractal dimension data analysis of fat cell structure. The conducted experiments confirm the feasibility of the proposed method to obtain quantitative information of the cellular processes. The results indicate that the proposed method is promising for estimating spatial changes of biological structure.
---
paper_title: Assessment of peripheral tissue perfusion by optical dynamic fluorescence imaging and nonlinear regression modeling

paper_content:

The purpose of this study is to examine the peripheral tissue perfusion rates by time-series analysis of ::: distribution and elimination kinetics of a clinically proven NIR fluorescence probe, indocyanine green (ICG). ::: We developed a new method, dynamic ICG perfusion imaging technique to evaluate peripheral tissue perfusion ::: that employs planar imaging with a CCD digital imaging system and time-series analysis of the spatiotemporal dynamics (150s) of intravenously injected ICG by using nonlinear regression and differential evolution methods. ::: Six parameters (α, β, s, d, m; parameters which depend on an arterial input function (AIF) into a lower extremity ::: and p; perfusion rates in the lower extremity) were estimated by the nonlinear regression modeling method. We ::: have confirmed the validity of our new method by applying the method to a normal control and a patient with ::: peripheral arterial occlusion disease (PAOD). PAOD patient showed a unique AIF curve pattern, which was ::: caused by collateral blood flow bypassing the occluded major artery. The lower extremity tissue perfusion rate ::: of the PAOD patient was estimated as about 35% of those of normal values. These results indicate that ICG ::: perfusion imaging method is sensitive enough to diagnose PAOD and capable of diagnosing functional arterial ::: diseases.
---
paper_title: Self-Assembly Synthesis, Tumor Cell Targeting, and Photothermal Capabilities of Antibody-Coated Indocyanine Green Nanocapsules

paper_content:

New colloidal materials that can generate heat upon irradiation are being explored for photothermal therapy as a minimally invasive approach to cancer treatment. The near-infrared dye indocyanine green (ICG) could serve as a basis for such a material, but its encapsulation and subsequent use are difficult to carry out. We report the three-step room-temperature synthesis of ∼120-nm capsules loaded with ICG within salt-cross-linked polyallylamine aggregates, and coated with antiepidermal growth factor receptor (anti-EGFR) antibodies for tumor cell targeting capability. We studied the synthesis conditions such as temperature and water dilution to control the capsule size and characterized the size distribution via dynamic light scattering and scanning electron microscopy. We further studied the specificity of tumor cell targeting using three carcinoma cell lines with different levels of EGFR expression and investigated the photothermal effects of ICG containing nanocapsules on EGFR-rich tumor cells. Signific...
---
paper_title: Indocyanine green (ICG) temporary clipping test to assess collateral circulation before venous sacrifice.

paper_content:

BACKGROUND ::: As a general principle, sacrifice of cerebral veins at surgery is avoided. However, at times sacrifice of a vein may be desirable to increase surgical exposure. At present, no method exists to predict whether such sacrifice will be accommodated by the presence of collateral venous drainage. We show a simple technique to examine cerebral venous blood flow using indocyanine green videoangiography. ::: ::: ::: METHODS ::: In two patients, parasagittal meningiomas were found to be associated with paramedian veins that impeded complete removal of the tumors. The suitability of veins removal was assessed by applying a temporary aneurysm clip and performing an indocyanine green videoangiogram. ::: ::: ::: RESULTS ::: In one patient, stasis was observed in the vein. In the second patient, a collateral flow allowed the venous blood to drain. The former test was considered a counterindication for venous sacrifice, whereas the latter supported its feasibility. The vein was preserved in the former case and coagulated in the latter. In both cases, the patients did well. ::: ::: ::: CONCLUSIONS ::: Although our limited study cannot prove that venous congestion or infarction can be avoided with this technique, it does provide direct evidence of the presence or absence of collaterals that can help guide intraoperative surgical decision-making.
---
paper_title: Near Infrared Fluorescence Imaging With Robotic Assisted Laparoscopic Partial Nephrectomy: Initial Clinical Experience for Renal Cortical Tumors

paper_content:

Purpose: We evaluated the utility of near infrared fluorescence of intravenously injected indocyanine green in performing robotic assisted laparoscopic partial nephrectomy. In addition, we evaluated the initial performance of a novel near infrared fluorescence imaging system integrated into the da Vinci® Si Surgical System during robotic assisted laparoscopic nephrectomy.Materials and Methods: Fluorescence imaging for the da Vinci Si Surgical System was used for all cases. Indocyanine green was injected before near infrared imaging. Immediate imaging assessed the renal vasculature while delayed imaging differentiated renal cortical tumors from normal parenchyma. The intraoperative performance of near infrared fluorescence of intravenous indocyanine green was evaluated for tumor appearance relative to surrounding renal parenchyma as well as identification of the renal vasculature.Results: A total of 11 patients underwent robotic assisted laparoscopic nephrectomy with 2 converted to robotic assisted laparos...
---
paper_title: All-optical anatomical co-registration for molecular imaging of small animals using dynamic contrast.

paper_content:

Optical molecular imaging in small animals harnesses the power of highly specific and biocompatible contrast agents for drug development and disease research1-7. However, the widespread adoption of in vivo optical imaging has been inhibited by its inability to clearly resolve and identify targeted internal organs. Optical tomography8-11 and combined X-ray and micro-computed tomography (micro-CT)12 approaches developed to address this problem are generally expensive, complex or incapable of true anatomical co-registration. Here, we present a remarkably simple all-optical method that can generate co-registered anatomical maps of a mouse's internal organs, while also acquiring in vivo molecular imaging data. The technique uses a time series of images acquired after injection of an inert dye. Differences in the dye's in vivo biodistribution dynamics allow precise delineation and identification of major organs. Such co-registered anatomical maps permit longitudinal organ identification irrespective of repositioning or weight gain, thereby promising greatly improved accuracy and versatility for studies of orthotopic disease, diagnostics and therapies.
---
paper_title: A Linear Correction for Principal Component Analysis of Dynamic Fluorescence Diffuse Optical Tomography Images

paper_content:

The analysis of dynamic fluorescence diffuse optical tomography (D-FDOT) is important both for drug delivery research and for medical diagnosis and treatment. The low spatial resolution and complex kinetics, however, limit the ability of FDOT in resolving drug distributions within small animals. Principal component analysis (PCA) provides the capability of detecting and visualizing functional structures with different kinetic patterns from D-FDOT images. A particular challenge in using PCA is to reduce the level of noise in D-FDOT images. This is particularly relevant in drug study, where the time-varying fluorophore concentration (drug concentration) will result in the reconstructed images containing more noise and, therefore, affect the performance of PCA. In this paper, a new linear corrected method is proposed for modeling these time-varying fluorescence measurements before performing PCA. To evaluate the performance of the new method in resolving drug biodistribution, the metabolic processes of indocyanine green within mouse is dynamically simulated and used as the input data of PCA. Simulation results suggest that the principal component (PC) images generated using the new method improve SNR and discrimination capability, compared to the PC images generated using the uncorrected D-FDOT images.
---
paper_title: Real-Time Simultaneous Near-Infrared Fluorescence Imaging of Bile Duct and Arterial Anatomy

paper_content:

Background We hypothesized that two independent wavelengths of near-infrared (NIR) fluorescent light could be used to identify bile ducts and hepatic arteries simultaneously, and intraoperatively. Materials and Methods Three different combinations of 700 and 800 nm fluorescent contrast agents specific for bile ducts and arteries were injected into N = 10 35-kg female Yorkshire pigs intravenously. Combination 1 (C-1) was methylene blue (MB) for arterial imaging and indocyanine green (ICG) for bile duct imaging. Combination 2 (C-2) was ICG for arterial imaging and MB for bile duct imaging. Combination 3 (C-3) was a newly developed, zwitterionic NIR fluorophore ZW800-1 for arterial imaging and MB for bile duct imaging. Open and minimally invasive surgeries were imaged using the fluorescence-assisted resection and exploration (FLARE) surgical imaging system and minimally invasive FLARE (m-FLARE) imaging systems, respectively. Results Although the desired bile duct and arterial anatomy could be imaged with contrast-to-background ratios (CBRs) ≥ 6 using all three combinations, each one differed significantly in terms of repetition and prolonged imaging. ICG injection resulted in high CBR of the liver and common bile duct (CBD) and prolonged imaging time (120 min) of the CBD (C-1). However, because ICG also resulted in high background of liver and CBD relative to arteries, ICG produced a lower arterial CBR (C-2) at some time points. C-3 provided the best overall performance, although C-2, which is clinically available, did enable effective laparoscopy. Conclusions We demonstrate that dual-channel NIR fluorescence imaging provides simultaneous, real-time, and high resolution identification of bile ducts and hepatic arteries during biliary tract surgery.
---
paper_title: A self-assembled multimodal complex for combined pre- and intraoperative imaging of the sentinel lymph node

paper_content:

Specific removal of the sentinel lymph node (SLN) during breast cancer surgery presents physicians with the opportunity to detect early metastatic disease. To increase the accuracy of intraoperative SLN detection, new methods with higher sensitivity and specificity are required. We have quantitatively compared conventional preoperative lymphoscintigraphy with albumin radiocolloids (99mTc-NanoColl) with optical intraoperative guidance using the near infrared dye indocyanine green (ICG) in an orthotopic mouse model for metastatic breast cancer. Furthermore, we have applied a self-assembled multimodal complex, in which ICG is non-covalently bound to the albumin radiocolloid, to attain identical dynamics of the radioactive and optical components. The SLN specificity of the multimodal complex is similar to conventional lymphoscintigraphy, while the fluorescent signal-to-noise ratio is improved by 86% compared to ICG alone. In addition, the multimodal complex permits scintigraphic validation of the fluorescent findings. The multimodal ICG–99mTc-NanoColl complex can be used both for lymphoscintigraphy by preoperative single photon emission computed tomography/computed tomography and for surgical navigation by intraoperative fluorescence imaging.
---
paper_title: Segmental analysis of indocyanine green pharmacokinetics for the reliable diagnosis of functional vascular insufficiency

paper_content:

Accurate and reliable diagnosis of functional insufficiency of peripheral vasculature is essential since Raynaud phenomenon (RP), most common form of peripheral vascular insufficiency, is commonly associated with systemic vascular disorders. We have previously demonstrated that dynamic imaging of near-infrared fluorophore indocyanine green (ICG) can be a noninvasive and sensitive tool to measure tissue perfusion. In the present study, we demonstrated that combined analysis of multiple parameters, especially onset time and modified T max which means the time from onset of ICG fluorescence to T max , can be used as a reliable diagnostic tool for RP. To validate the method, we performed the conventional thermographic analysis combined with cold challenge and rewarming along with ICG dynamic imaging and segmental analysis. A case-control analysis demonstrated that segmental pattern of ICG dynamics in both hands was significantly different between normal and RP case, suggesting the possibility of clinical application of this novel method for the convenient and reliable diagnosis of RP.
---
paper_title: Intraoperative near-infrared indocyanine green–videoangiography (ICG–VA) and graphic analysis of fluorescence intensity in cerebral aneurysm surgery

paper_content:

We present our preliminary experience with intraoperative near-infrared indocyanine green-videoangiography (ICG-VA) and analysis of blood flow dynamics using fluorescence intensity assessment in cerebral aneurysm clipping surgery. Thirty-nine patients with 43 intracranial aneurysms underwent microsurgical clipping. Intraoperative ICG-VA was performed before and after clip application. An infrared fluorescence module integrated into a surgical microscope was used to visualize fluorescence in the surgical field and we recorded the emitted fluorescent light. An integrated analytical visualization tool simultaneously analyzed the video sequence and converted it into an intensity diagram, which allowed an objective evaluation of the results rather than the subjective assessment of fluorescence using ICG-VA. Overall, ICG-VA was performed 137 times. Incomplete clipping was detected in four patients, which allowed suitable adjustment to completely obliterate the aneurysm. In 12 patients, perforators arising close to, or from, the aneurysmal neck were identified in the surgical field. In three patients, the ICG-VA intensity diagram provided valuable information leading to modification of the primary surgical maneuver. ICG-VA provides high resolution images allowing real-time assessment of the blood flow in the parent artery and arterial branches, including the perforators. The intensity diagram is useful for providing a more objective record of the hemodynamics than the traditional ICG-VA, which relies more on subjective assessment and may allow interobserver variability. We conclude that ICG-VA, combined with the intensity diagram, can reduce the morbidity and complications associated with aneurysm clipping and improve patient outcomes.
---
paper_title: Photoacoustic flow cytometry: principle and application for real-time detection of circulating single nanoparticles, pathogens, and contrast dyes in vivo

paper_content:

The goal of this work is to develop in vivo photoacoustic PA flow cytometry PAFC for time-resolved detection of circulating absorbing objects, either without labeling or with nanoparticles as PA labels. This study represents the first attempt, to our knowledge, to demonstrate the capability of PAFC with tunable near-infrared NIR pulse lasers for real-time monitoring of gold nanorods, Staphylococ- cus aureus and Escherichia coli labeled with carbon nanotubes CNTs, and contrast dye Lymphazurin in the microvessels of mouse and rat ears and mesenteries. PAFC shows the unprecedented thresh- old sensitivity in vivo as one gold nanoparticle in the irradiated vol- ume and as one bacterium in the background of 10 8 of normal blood cells. The CNTs are demonstrated to serve as excellent new NIR high-PA contrast agents. Fast Lymphazurin diffusion in live tissue is observed with rapid blue coloring of a whole animal body. The en- hancement of the thermal and acoustic effects is obtained with clus- tered, multilayer, and exploded nanoparticles.This novel combination of PA microscopy/spectroscopy and flow cytometry may be consid- ered as a new powerful tool in biological research with the potential of quick translation to humans, providing ultrasensitive diagnostics of pathogens e.g., bacteria, viruses, fungi, protozoa, parasites, helm- inthes, metastatic, infected, inflamed, stem, and dendritic cells, and pharmacokinetics of drug, liposomes, and nanoparticles in deep ves- sels with focused transducers among other potential applications. ©
---
paper_title: Calibration of diffuse correlation spectroscopy with a time-resolved near-infrared technique to yield absolute cerebral blood flow measurements

paper_content:

Abstract: The authors provide corrections to tabular data and a figure, which do not alter the conclusions of the original paper [Biomed. Opt. Express 2, 2068 (2011)].
---

Title: A Review of Indocyanine Green Fluorescent Imaging in Surgery

Section 1: Introduction
Description 1: This section provides an overview of Fluorescence Imaging (FI) in biomedical sciences, highlighting its benefits and the specific potential of indocyanine green (ICG) imaging in surgery.

Section 2: Indocyanine Green Angiography
Description 2: This section discusses the use of indocyanine green in ophthalmology for imaging retinal blood vessels and the principles behind ICG angiography (ICGA).

Section 3: Related Work
Description 3: This section reviews existing literature and previous studies related to ICG and ICGA across various biomedical fields.

Section 4: ICG Publications
Description 4: This section analyzes the volume of research activities and publications related to ICG, noting the areas of focus and the need for more technical research.

Section 5: Properties of Indocyanine Green
Description 5: This section covers the principal advantages, absorption and emission spectra, low toxicity, and rapid excretion of ICG, making it suitable for medical imaging.

Section 6: Structure and Stability
Description 6: This section details the chemical structure and stability of indocyanine green, including solubility, and methods to stabilize ICG.

Section 7: Spectral Stability
Description 7: This section explains the spectral stability of ICG in different environments and its impact on imaging.

Section 8: Photochemical Stability
Description 8: This section discusses the photochemical properties of ICG, including singlet oxygen production and phototoxicity.

Section 9: Protein Binding and Fluorescence Life-Time
Description 9: This section describes how ICG binds to plasma proteins and its effect on fluorescence efficiency and stability.

Section 10: Physiology and Pharmacokinetics
Description 10: This section reviews the physiological behavior and pharmacokinetics of ICG, including its rapid liver extraction and clinical applications.

Section 11: Penetration
Description 11: This section highlights the penetration capabilities of ICG in tissues and its implications for imaging vascular structures.

Section 12: ICG Derivatives and ICG-Like Contrast Agents
Description 12: This section explores the development of new ICG derivatives and other near-infrared fluorescent (NIRF) dyes for biomedical applications.

Section 13: Instrumentation
Description 13: This section provides an overview of the instrumentation required for ICG imaging, including fluorescence microscopy and operational microscopes.

Section 14: Fluorescence Imaging
Description 14: This section explains the techniques and tools used in fluorescence imaging, emphasizing the importance of image registration and suitable filtering.

Section 15: Example of an ICGA Device Design
Description 15: This section outlines the design principles of a simple ICGA device, including schematic diagrams and filter selection.

Section 16: Test and Background Light
Description 16: This section discusses the use of test and background light in ensuring the functionality of the camera system for ICG fluorescence wavelengths.

Section 17: Optics
Description 17: This section details the optical components required for ICG imaging, including the use of LED lights and microscopes.

Section 18: ICGA Test
Description 18: This section describes the testing and validation of ICG angiography devices in laboratory and clinical settings.

Section 19: Surgical Applications
Description 19: This section covers the established and emerging surgical applications of ICG, including retinal angiography, liver clearance test, and cardiac output monitoring.

Section 20: Intraoperational Angiography
Description 20: This section describes the use of ICG angiography in various intraoperative settings, such as neurosurgery, coronary surgery, and vascular surgery.

Section 21: Coronary Surgery
Description 21: This section examines the application of ICG angiography in coronary artery bypass grafting (CABG) and other cardiac surgeries.

Section 22: Vascular Surgery
Description 22: This section reviews ICG fluorescence imaging's role in vascular surgery for graft patency, peripheral arterial disease, and other uses.

Section 23: Oncology and Sentinel Lymph Node Harvesting
Description 23: This section discusses the use of ICG for identifying lymph nodes and performing sentinel lymph node biopsies in cancer surgeries.

Section 24: Liver Surgery and Laparoscopy
Description 24: This section covers the application of ICG in liver surgery and laparoscopic procedures for visualizing liver segments and detecting hepatocellular carcinoma.

Section 25: Laparoscopic Cholecystectomy
Description 25: This section describes the use of ICG for aiding bile examination and performing cholecystectomy procedures.

Section 26: Reconstructive Microsurgery
Description 26: This section explores the use of ICG in assessing flap viability and microvascular anastomosis in reconstructive surgeries.

Section 27: Other Clinical Applications
Description 27: This section highlights other clinical applications of ICG, including brain imaging, rheumatology, trauma, and muscle perfusion.

Section 28: Photodynamic and Photothermal Therapy
Description 28: This section explains the potential of ICG in photodynamic and photothermal therapies for applications like fat cell destruction and antibacterial treatments.

Section 29: Dyeing
Description 29: This section discusses the use of ICG as a dye for tattooing, labeling, and other similar tasks.

Section 30: Conclusions
Description 30: This section provides a summary of the review, emphasizing the current state and future potential of ICG fluorescent imaging in clinical applications.