Hydronephrosis on Prior Imaging Unknown Cause. Please note that this variant describes initial imaging evaluation after the discovery, by imaging or otherwise, of asymptomatic hydronephrosis in a pregnant patient with unknown cause. The choice of initial imaging in this situation is dependent on clinical context and on the information available from the means of hydronephrosis discovery (eg, CT, MR, US). CT Abdomen and Pelvis With IV Contrast There is limited evidence to support the use of CT abdomen and pelvis with IV contrast (separate from CTU) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. CT Abdomen and Pelvis Without and With IV Contrast There is limited evidence to support the use of CT abdomen and pelvis without and with IV contrast (separate from CTU) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. Hydronephrosis on Prior Imaging-Unknown Cause CT Abdomen and Pelvis Without IV Contrast There is limited evidence to support the use of CT abdomen and pelvis without IV contrast (separate from CTU) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. CT Abdomen With IV Contrast There is limited evidence to support the use of CT abdomen with IV contrast (separate from CTU) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. CT Abdomen Without and With IV Contrast There is limited evidence to support the use of CT abdomen without and with IV contrast (separate from CTU) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. CT Abdomen Without IV Contrast There is limited evidence to support the use of CT abdomen without IV contrast (separate from CTU) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause.


Hydronephrosis on Prior Imaging Unknown Cause. CTU Without and With IV Contrast There is limited evidence to support the use of CTU without and with IV contrast for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. DTPA Renal Scan Although DRG is the de facto standard of care in diagnosis of renal obstruction [10] and can be used to determine whether obstructive uropathy is truly present in cases of incidentally noted hydronephrosis or in suspected obstruction of renal transplant [11], DRG is not preferred for initial imaging in pregnant patients. Note that use of DTPA for diuretic renography may result in an equivocal or false-positive diuretic study compared with MAG3, particularly in patients with reduced function, and is not favored [11,12]. DRG with DTPA can also be used to estimate single-kidney GFR but may somewhat overestimate global GFR in the setting of obstructive hydronephrosis [13]. Fluoroscopy Antegrade Pyelography There is limited evidence to support the use of fluoroscopic antegrade pyelography for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. Fluoroscopy Voiding Cystourethrography There is limited evidence to support the use of fluoroscopic voiding cystourethrography for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. MAG3 Renal Scan Although DRG is the de facto standard of care in diagnosis of renal obstruction [10] and can be used to determine whether obstructive uropathy is truly present in cases of incidentally noted hydronephrosis or in suspected obstruction of renal transplant [11], DRG is not preferred for initial imaging in pregnant patients. MRI Abdomen and Pelvis Without and With IV Contrast There is limited evidence to support the use of MRI abdomen and pelvis without and with IV contrast (separate from MRU) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause.


Hydronephrosis on Prior Imaging Unknown Cause. Gadolinium contrast administration is avoided during pregnancy and should be considered only if the imaging is essential and cannot be delayed [42] or replaced by alternative imaging. MRI Abdomen and Pelvis Without IV Contrast Although there is limited evidence to support the use of MRI abdomen and pelvis without IV contrast (separate from MRU) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause, it may be useful in this setting in some clinical situations. MRU without IV contrast may provide additional information in this setting. MRI Abdomen Without and With IV Contrast There is limited evidence to support the use of MRI abdomen without and with IV contrast (separate from MRU) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. Gadolinium contrast administration is avoided during pregnancy and should be considered only if the imaging is essential and cannot be delayed [42] or replaced by alternative imaging. Hydronephrosis on Prior Imaging-Unknown Cause MRI Abdomen Without IV Contrast There is limited evidence to support the use of MRI abdomen without IV contrast (separate from MRU) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. MRU Without and With IV Contrast There is limited evidence to support the use of MRU without and with IV contrast for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. Gadolinium contrast administration is avoided during pregnancy and should be considered only if the imaging is essential and cannot be delayed [42] or replaced by alternative imaging. MRU Without IV Contrast Although there is limited evidence to support the use of MRU without IV contrast for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause, MRU without IV contrast is preferred over CTU in pregnant patients [15].


Hydronephrosis on Prior Imaging Unknown Cause. MRU without IV contrast may be useful in this setting in some clinical situations and can be combined with anatomical imaging to provide more information than anatomical imaging alone. Radiography Abdomen and Pelvis There is limited evidence to support the use of radiography of the abdomen and pelvis for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. Radiography Intravenous Urography There is limited evidence to support the use of radiography with IVU (also referred to as IVP) for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. Historically, IVP was used to evaluate hydronephrosis, but this study is considered obsolete in many settings [6]. US Abdomen There is relatively limited evidence to support the use of US of the abdomen for initial imaging of pregnant patients with asymptomatic hydronephrosis with unknown cause. It may be useful if there is clinical concern for specific causes identifiable by transabdominal US, although the gravid uterus may limit sonographic evaluation of abdominopelvic structures. US abdomen is a less comprehensive examination of the genitourinary system than MRU without IV contrast or US color Doppler kidneys and bladder retroperitoneal. Variant 5: Adult. Symptomatic hydronephrosis in a pregnant patient with unknown cause. Initial imaging. Please note that this variant describes initial imaging evaluation after the discovery, by imaging or otherwise, of symptomatic hydronephrosis in a pregnant patient with unknown cause. The choice of initial imaging in this situation is dependent on clinical context and on the information available from the means of hydronephrosis discovery (eg, CT, MR, US). CT Abdomen and Pelvis With IV Contrast There is limited evidence to support the use of CT abdomen and pelvis with IV contrast (separate from CTU) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause.


Hydronephrosis on Prior Imaging Unknown Cause. CT should be reserved for problematic situations in which a diagnosis cannot be made on US or MRI [17]. When CT is required, a low- dose CT protocol should be used [6]. CT Abdomen and Pelvis Without and With IV Contrast There is limited evidence to support the use of CT abdomen and pelvis without and with IV contrast (separate from CTU) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. CT should be reserved for problematic situations in which a diagnosis cannot be made on US or MRI [17]. When CT is required, a low-dose CT protocol should be used [6]. Hydronephrosis on Prior Imaging-Unknown Cause CT Abdomen and Pelvis Without IV Contrast There is limited evidence to support the use of CT abdomen and pelvis without IV contrast (separate from CTU) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. CT should be reserved for problematic situations in which a diagnosis cannot be made on US or MRI [17]. When CT is required, a low-dose CT protocol should be used [6]. CT Abdomen With IV Contrast There is limited evidence to support the use of CT abdomen with IV contrast (separate from CTU) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. CT Abdomen Without and With IV Contrast There is limited evidence to support the use of CT abdomen without and with IV contrast (separate from CTU) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. CT Abdomen Without IV Contrast There is limited evidence to support the use of CT abdomen without IV contrast (separate from CTU) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. CTU Without and With IV Contrast There is limited evidence to support the use of CTU without and with IV contrast for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause.


Hydronephrosis on Prior Imaging Unknown Cause. CT should be reserved for problematic situations in which a diagnosis cannot be made on US or MRI [17]. When CT is required, a low-dose CT protocol should be used [6]. DTPA Renal Scan Although DRG is the de facto standard of care in diagnosis of renal obstruction [10] and can be used to determine whether obstructive uropathy is truly present in cases of incidentally noted hydronephrosis or in suspected obstruction of renal transplant [11], DRG is not preferred for initial imaging in pregnant patients. Note that use of DTPA for diuretic renography may result in an equivocal or false-positive diuretic study compared with MAG3, particularly in patients with reduced function, and is not favored [11,12]. DRG with DTPA can also be used to estimate single-kidney GFR but may somewhat overestimate global GFR in the setting of obstructive hydronephrosis [13]. Fluoroscopy Antegrade Pyelography There is limited evidence to support the use of fluoroscopic antegrade pyelography for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. Fluoroscopy Voiding Cystourethrography There is limited evidence to support the use of fluoroscopic voiding cystourethrography for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. MAG3 Renal Scan Although DRG is the de facto standard of care in diagnosis of renal obstruction [10] and can be used to determine whether obstructive uropathy is truly present in cases of incidentally noted hydronephrosis or in suspected obstruction of renal transplant [11], DRG is not preferred for initial imaging in pregnant patients. MRI Abdomen and Pelvis Without and With IV Contrast There is limited evidence to support the use of MRI abdomen and pelvis without and with IV contrast (separate from MRU) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause.


Hydronephrosis on Prior Imaging Unknown Cause. Gadolinium contrast administration is avoided during pregnancy and should be considered only if the imaging is essential and cannot be delayed [42] or replaced by alternative imaging. MRI Abdomen and Pelvis Without IV Contrast There is limited evidence to support the use of MRI abdomen and pelvis without IV contrast (separate from MRU) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause, although MRI can play a useful adjunct role in pregnant patients with renal colic and equivocal or nondiagnostic initial US findings [17]. Hydronephrosis on Prior Imaging-Unknown Cause MRI Abdomen Without and With IV Contrast There is limited evidence to support the use of MRI abdomen without and with IV contrast (separate from MRU) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. Gadolinium contrast administration is avoided during pregnancy and should be considered only if the imaging is essential and cannot be delayed [42] or replaced by alternative imaging. MRI Abdomen Without IV Contrast There is limited evidence to support the use of MRI abdomen without IV contrast (separate from MRU) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause, although MRI can play a useful adjunct role in pregnant patients with renal colic and equivocal or nondiagnostic initial US findings [17]. MRU Without and With IV Contrast There is limited evidence to support the use of MRU without and with IV contrast for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. Gadolinium contrast administration is avoided during pregnancy and should be considered only if the imaging is essential and cannot be delayed [42] or replaced by alternative imaging. MRU Without IV Contrast There is some evidence for use of MRU without IV contrast for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause.


Hydronephrosis on Prior Imaging Unknown Cause. Although it can be performed independently, MRU can also be performed at the time of structural MRI. In a study of 24 pregnant patients with symptomatic hydronephrosis, MRU was noted to show different appearances in physiologic hydronephrosis and pathologic obstruction [44]. Multiple authors suggest that noncontrast MRU should be considered after an equivocal or nondiagnostic US in symptomatic pregnant patients with suspected urolithiasis [6,17]. In a prospective study of 55 nonpregnant patients with hydronephrosis detected on US for urologic symptoms, excluding patients with abnormal renal function given contraindication for IVU, Muthusami et al [30] compared static heavily T2-weighted MRU to reference IVU and determined that MRU had high sensitivity and specificity for detecting (95% and 100%, respectively) and grading (Spearman correlation coefficient 0.92) hydronephrosis, as well as identifying the location of obstruction (90% and 99%, respectively) if present. The authors conclude that static MRU can replace IVU when the latter is contraindicated or technically difficult. The authors note that MRU sensitivity for hydronephrosis grading increased with grade of obstruction. Radiography Abdomen and Pelvis There is limited evidence to support the use of radiography of the abdomen and pelvis for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. Radiography Intravenous Urography There is limited evidence to support the use of radiography with IVU (also referred to as IVP) for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. Historically, IVP was used to evaluate symptomatic pregnant patients suspected to have renal obstruction; however, due to radiation exposure, IV contrast administration and increased usage of cross-sectional imaging, this study is considered obsolete in many settings [6].


Hydronephrosis on Prior Imaging Unknown Cause. US Abdomen There is relatively limited evidence to support the use of US of the abdomen for initial imaging of pregnant patients with symptomatic hydronephrosis with unknown cause. It may be useful if there is clinical concern for specific causes identifiable by transabdominal US, although the gravid uterus may limit sonographic evaluation of abdominopelvic structures. US abdomen is a less comprehensive examination of the genitourinary system than MRU without IV contrast or US color Doppler kidneys and bladder retroperitoneal. US Color Doppler Kidneys and Bladder Retroperitoneal US is the first-line study for diagnosis of maternal hydronephrosis or renal anatomic abnormalities [5,17,43]. In the pregnant patient with known, symptomatic hydronephrosis, specific findings on US including anteroposterior 21 Hydronephrosis on Prior Imaging-Unknown Cause diameter of the renal pelvis and renal RI can help differentiate benign pregnancy-related hydronephrosis and pathologic obstruction and can help predict the need for intervention. In a prospective single-center study of 1,026 pregnant patients including 295 with hydronephrosis, Bayraktar et al [5] reported a correlation between anteroposterior diameter of the renal pelvis on US and requirement for intervention for symptomatic patients. Ercil et al [9] report the same finding in a retrospective single-center series of 246 pregnant patients with symptomatic hydronephrosis, noting that a diameter above 21 mm on the right had a sensitivity of 91% and a specificity of 84% for predicting intervention, and a diameter above 25 mm on the left had a sensitivity and specificity of 100%. Demir et al [45] reported in a study of 227 pregnant women with symptomatic hydronephrosis that intervention was found to be necessary with renal pelvis anteroposterior diameter >16.5 mm in the first two trimesters and >27.5 mm in the third trimester.


Noninvasive Clinical Staging of Primary Lung Cancer PCAs.  Introduction/Background Lung cancer is the leading cause of cancer-related deaths in both men and women. While the incidence of the disease for men in the United States has been steadily decreasing since the 1970s, the incidence for women in the United States increased after 1975 before leveling in the 2000s [1]. The major risk factor for lung cancer is personal tobacco smoking, particularly for small-cell lung cancer (SCLC) and squamous-cell lung cancers, but other significant risk factors include exposure to second-hand smoke, environmental radon, occupational exposures, and air pollution. Education and socioeconomic status affect both incidence and outcomes, with a disproportionate amount of the disease burden seen in the poor and poorly educated. The economic cost of caring for lung cancer patients in the United States is over $12 billion per year. Mortality cost from lost productivity also numbers in the billions of dollars [2]. aThe University of Texas MD Anderson Cancer Center, Houston, Texas. bPanel Chair, University of Chicago, Chicago, Illinois. cMassachusetts General Hospital and Harvard Medical School, Boston, Massachusetts. dStanford University Medical Center, Stanford, California; The Society of Thoracic Surgeons. eThe University of Texas MD Anderson Cancer Center, Houston, Texas. fUniversity of Southern California, Los Angeles, California. gUniversity of Kentucky, Lexington, Kentucky. hMayo Clinic, Jacksonville, Florida. iHenry Ford Cancer Institute, Detroit, Michigan. jDuke University School of Medicine, Durham, North Carolina; The Society of Thoracic Surgeons. kUniversity of Kansas Medical Center, Kansas City, Kansas. lUniversity of California San Francisco, San Francisco, California. mSpecialty Chair, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through society representation on expert panels. Participation by representatives from collaborating societies on the expert panel does not necessarily imply individual or society endorsement of the final document. Reprint requests to: publications@acr.org N Descriptor The eighth edition makes no changes from the previous edition with regard to metastatic nodal disease. The N stage is based on location of metastatic nodes. Increasing number of involved nodal stations negatively affects prognosis [5]. A lymph node size threshold of >10 mm in axial short axis diameter is considered abnormal. The prevalence of metastatic lung cancer in thoracic lymph nodes is 30% for nodes that are 10 to 15 mm in short axis diameter and 67% for nodes >15 mm [7]. Axillary lymph node metastasis occurs in 0.75% of lung cancers [8]. It is not included in the N descriptor but is considered metastatic M1 disease. Nx indicates that lymph nodes cannot be assessed [5]. N0 is consistent with lack of regional node involvement [5]. N1 includes ipsilateral peribronchial, hilar or intrapulmonary lymph node(s) [5]. N2 describes ipsilateral mediastinal or subcarinal lymph node(s) [5]. N3 includes contralateral mediastinal or hilar lymph node(s) and any supraclavicular or scalene node on either side [5]. M Descriptor The presence of metastatic lung cancer lesions constitutes stage IV disease. Many patients with NSCLC present with metastatic disease [9], and the treatment of stage IV cancers depends on the location and number of lesions. M0 disease is consistent with no distant metastases [5]. The M1 classification is subdivided into three categories: M1a includes satellite nodule(s) in the contralateral lung and cytology proven malignant pleural or pericardial effusion [5]. M1b indicates a single extrathoracic metastasis.


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. This category also includes metastasis in a single nonregional lymph node, considered nodes not in the N descriptor, such as enlarged axillary, internal mammary, and/or abdominal lymph node [5,6]. M1c indicates multiple extrathoracic metastases in one or more organs [5]. Stage Groups for NSCLC Stage groupings have been revised according to statistically significant differences in survival among tumors in the database. The eighth edition includes new differentiation among stage IA tumors based on size of the tumor and a new stage IIIC category for T3 and T4 tumors with N3M0 disease [6]. Classification of mucinous adenocarcinomas is also addressed. The T descriptor is based on size if confined to a single lobe. The tumor is designated as T3 if size cannot be determined but remains in a single lobe. Involvement of multiple ipsilateral lobes is T4 disease. Bilateral lesions are considered M1a [5,10]. CT Chest For patients with known or suspected NSCLC, a chest CT with intravenous (IV) contrast is recommended. A chest CT without IV contrast may also be obtained. Noninvasive Clinical Staging of Primary Lung Cancer Chest CT is the modality of choice for initial evaluation of the T descriptor, specifically the size and location of the primary tumor. Diagnosis of chest wall or mediastinal invasion on CT can be equivocal in cases of minimal invasion. Radiologic imaging cannot consistently detect visceral pleural invasion. Chest CT with IV contrast can aid in the identification of mediastinal or chest wall invasion by tumor, evaluation of hilar lymph nodes, distinction of central obstructing tumor from surrounding atelectasis, and assessment for liver metastases [11,12]. Chest CT without IV contrast is often better able to characterize adrenal nodules than chest CT with contrast, but the benefit of a noncontrast chest CT for this purpose may be obviated by performance of PET or PET/CT.


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. Accurate N staging of the mediastinum is important in distinguishing resectable from unresectable disease. CT staging of nodal disease in the mediastinum is inadequate because of its low sensitivity and specificity of anatomic size criteria [11]. A meta-analysis of over 7,000 patients found that the prevalence of mediastinal lymph node metastasis was 30%. However, the median sensitivity of contrast-enhanced CT was 55%, and median specificity was 81% for mediastinal nodal disease using the >10-mm short axis diameter criteria [11]. Findings on chest CT of enlarged mediastinal nodes aids in guiding biopsy, as invasive staging of the mediastinum is recommended over imaging alone [11]. The distribution of mediastinal lymph node metastases is influenced by the location of the primary tumor. Right upper lobe tumors drain to the right paratracheal nodes (2R and 4R), while right middle and lower lobe tumors most frequently drain to the lower right paratracheal and subcarinal nodes (4R and 7R). Nodal metastases for the left upper lobe are most often seen in the aorticopulmonary window and prevascular nodes (5L and 6L). Left lower lobe tumors drain to the prevascular and subcarinal nodes (6L and 7L) [13]. Tumors in the lower lobe superior segments frequently have upper mediastinal lymph node involvement (64%) compared with basal segment tumors [14]. Chest CT is adequate for the identification of contralateral lung nodules constituting M1a disease. It also identifies pleural or pericardial effusions that may need cytological confirmation if pleural or pericardial nodules are not visible. Extrathoracic M1b metastases of the adrenal glands and bone structures may be seen on a chest CT. However, adrenal nodules may not be definitively characterized by CT if IV contrast is used or if intracytoplasmic lipid content is low, which occurs in approximately one-third of adrenal adenomas.


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. Techniques for further evaluation include PET using the tracer fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG) with CT, CT adrenal washout protocol, and MR chemical shift of in- and out-of-phase imaging [15]. Liver metastases may be seen if they occur within the included segments on chest CT and are better identified on contrast-enhanced studies, particularly if lesions are small. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT is recommended to evaluate for extrathoracic metastases in patients with NSCLC. It is not required for patients with stage 0 adenocarcinoma in situ with an otherwise normal chest CT examination. FDG-PET is reported to change management in 14% to 26% of NSCLC patients [16-18]. FDG-PET imaging is superior to CT in detection of nodal and distant metastases [19]. FDG-PET may upstage NSCLC by identifying metastases that were occult on CT imaging or downstage the malignancy by demonstrating lack of glucose metabolism in a suspected lesion [20]. Integrated FDG-PET/CT is more accurate for staging of the N and M descriptors than independent FDG-PET or diagnostic CT [21]. FDG-PET or PET/CT is reported to reduce futile thoracotomies by 20% and 17%, respectively [19,22]. FDG-PET has sensitivity of 94% and specificity of 82% for characterization of adrenal nodules and is superior to CT alone. Lack of FDG uptake in an adrenal nodule is considered conclusive for benign adrenal adenoma and obviates further workup [31]. Patients with an FDG-avid adrenal nodule as the only site of potential metastatic disease require biopsy confirmation [11]. The sensitivity, specificity, accuracy, and negative predictive value of FDG-PET for bone metastases are >90%, which is superior to bone scintigraphy [32-35]. Liver metastases may be present in up to 3% to 4% of asymptomatic NSCLC patients at the time of presentation [36].


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. Although there is heterogeneous physiologic FDG activity in the liver, the accuracy of FDG-PET and PET/CT for liver metastases is reported to be 92% to 100% [37]. When findings are discordant or indeterminate, MRI and/or biopsy are appropriate strategies to evaluate liver lesions. FDG-PET cannot be used for tumor measurement purposes, but integrated PET/CT allows anatomic measurement on the CT portion of the examination for the T descriptor. CT Abdomen and Pelvis CT abdomen and pelvis with oral and IV contrast may be used as an alternate imaging modality to evaluate for extrathoracic metastasis in lung cancer patients being considered for curative therapy if FDG-PET or PET/CT is not performed [11]. Acquisitions of arterial and portal venous phase sequences are advised. CT abdomen and pelvis with oral and IV contrast is recommended in NSCLC patients with abnormal clinical evaluation, including signs or symptoms referable to the abdomen and pelvis and no suspicious extrathoracic findings on chest CT [11]. All NSCLC with locally advanced stage III or stage IV disease should undergo extrathoracic imaging with either CT abdomen and pelvis or FDG-PET or PET/CT because of the likelihood of occult extrathoracic metastatic disease in up to 37% of cases [11]. Bone Scan Whole Body Technetium-99m (Tc-99m) bone scintigraphy may be used as an alternate imaging modality to evaluate for bone metastasis in NSCLC patients if FDG-PET or PET/CT is not performed or is equivocal for osseous findings. Bone scintigraphy was historically used to detect osseous metastatic disease in lung cancer patients. A recent meta-analysis found it has a pooled sensitivity of 91.8%; however, the pooled specificity for bone metastases from lung cancer on bone scintigraphy was 68.8%, which is primarily due to confounders such as degenerative disease, inflammation, and prior trauma [38].


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. FDG-PET and PET/CT have significantly higher sensitivity, specificity, accuracy, and negative predictive value than bone scan [34,35]. MRI Brain MRI brain without and with IV contrast is recommended in any patient with clinical stage II, III, or IV NSCLC, even in the absence of neurologic symptoms [39]. MRI brain without and with IV contrast is optional in patients with clinical stage IB NSCLC without neurologic symptoms [39]. MRI brain without and with IV contrast is recommended in all NSCLC patients with neurologic symptoms, regardless of stage. MRI brain is the preferred imaging modality for evaluation of intracranial metastases, as it is more sensitive for small brain lesions than CT [11,40]. In a meta-analysis of NSCLC patients without neurologic symptoms, the median prevalence of brain lesions was 3% [11]. However, a small study found that 22% of asymptomatic patients with tumor size >3 cm had brain metastases [41]. Any NSCLC patient with neurologic symptoms should be screened for intracranial metastasis [11]. Brain metastases have been associated with adenocarcinoma NSCLC and N2 disease [11,42]. CT Head CT head with IV contrast can be used as an alternate imaging modality in stage III or IV NSCLC patients and NSCLC patients with neurologic symptoms if MRI head is not obtained. Dual-phase imaging may be useful in this clinical setting. CT scanning of the brain is an appropriate method of evaluating for brain metastases in patients with NSCLC [11]. Although MRI has greater sensitivity than CT, the identification of more and smaller brain lesions on MRI compared with CT has not been associated with better survival or the identification of more patients with brain lesions [43,44]. Noninvasive Clinical Staging of Primary Lung Cancer MRI Chest MRI chest without and with IV contrast may be indicated in specific clinical circumstances in NSCLC patients with equivocal findings on CT chest.


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. Focused MRI of the chest may be useful in assessment of chest wall or spinal invasion and tumor involvement of mediastinal structures, including the heart, great vessels, and pericardium. MRI assessment of superior sulcus tumors for brachial plexus involvement is standard of care [45]. MRI is superior to CT for detecting involvement of the neural foramina and spinal canal. Dynamic cine MRI with free breathing can determine lack of invasion if there is respiration-coordinated sliding between the tumor and mediastinum or chest wall, and it can also evaluate for phrenic nerve involvement by lymphadenopathy or the primary tumor. Conversely, restriction of tumor motion is not conclusive since inflammation or adhesion may also affect mobility [46,47]. MRI is also capable of distinguishing an obstructing tumor from postobstructive atelectasis. Diffusion- weighted imaging (DWI) has been shown to be equal to PET/CT in differentiation of tumor and atelectasis. In the same study, T2-weighted imaging was accurate in 76% of cases [48]. MRI Abdomen MRI abdomen with chemical shift sequencing may be used to characterize adrenal nodules when findings on CT chest or CT abdomen are equivocal and FDG-PET or PET/CT is not performed. Indeterminate adrenal nodules may be characterized by chemical shift of in- and out-of-phase MRI to assess for the presence of small intracytoplasmic lipid volume in lipid-poor adenomas. Use of MRI for this purpose is declining because of the high sensitivity and accuracy of PET/CT in identifying adrenal metastases from lung cancer [31]. MRI abdomen with IV contrast may be used to identify small metastatic lesions in the liver when findings are equivocal on CT chest, CT abdomen, FDG-PET, or PET/CT. MRI abdomen with IV contrast has a higher sensitivity than CT, FDG-PET, or PET/CT for detection and characterization of small liver lesions and may be used for more definitive characterization [49].


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. Radiography Chest Chest radiography is not sufficient for staging of NSCLC. Variant 2: Noninvasive initial clinical staging of small-cell lung carcinoma. SCLC is an aggressive form of primary pulmonary neuroendocrine tumor with short doubling time and tendency toward early metastasis [50]. The eighth edition of the TNM staging criteria of the American Joint Committee on Cancer applies to patients with SCLC. The TNM staging criteria is recommended to be used in conjunction with the modified Veterans Administration Lung Study Group (VALSG) classification system distinguishing limited stage (LS) from extensive stage (ES) SCLC because of the ongoing use of the VALSG 2-stage classification system in general clinical practice and clinical trials [51-53]. The 5-year overall survival for LS-SCLC is 20% to 25%, while 5-year survival for ES-SCLC approaches zero [51]. The eighth edition of the TNM criteria of the American Joint Committee on Cancer was developed under the auspices of the International Association for the Study of Lung Cancer and informed by database analysis of nearly 95,000 patients primarily from Europe and Asia [4]. Clinical noninvasive staging by radiologic imaging is the first step in determining the appropriate management for patients with SCLC. Noninvasive Clinical Staging of Primary Lung Cancer N Descriptor In the eighth edition, the N stage is based on location of metastatic nodes. Increasing number of involved nodal stations negatively affects prognosis [5]. A lymph node size threshold of >10 mm in axial short axis diameter is considered abnormal. The prevalence of metastatic lung cancer in thoracic lymph nodes is 30% for nodes that are 10 to 15 mm in short axis diameter and 67% for nodes >15 mm [7]. Nx indicates that lymph nodes cannot be assessed [5]. N0 is consistent with lack of regional node involvement [5]. N1 includes ipsilateral peribronchial, hilar, or intrapulmonary lymph node(s) [5].


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. N2 describes ipsilateral mediastinal or subcarinal lymph node(s) [5]. N3 includes contralateral mediastinal or hilar lymph node(s) and any supraclavicular or scalene node on either side [5]. M Descriptor The presence of metastatic lung cancer lesions constitutes stage IV disease. Many patients with SCLC present with metastatic disease [9], and the treatment of stage IV cancers depends on the location and number of lesions. M0 disease is consistent with no distant metastases [5]. The M1 classification is subdivided into three categories: M1a includes satellite nodule(s) in the contralateral lung and cytology proven malignant pleural or pericardial effusion [5]. M1b indicates a single extrathoracic metastasis. This category also includes metastasis in a single nonregional lymph node, considered nodes not in the N descriptor, such as axillary, internal mammary, or abdominal lymph node(s) [5,6]. M1c indicates multiple extrathoracic metastases in one or more organs [5]. Modified VALSG Staging Under the modified VALSG staging classification, SCLC is considered LS disease when it is confined to a single hemithorax (although local extension may be present); the primary tumor and regional nodes can be addressed by a single radiation port; and ipsilateral supraclavicular nodes can be included in the same radiation field as the primary tumor. Contralateral mediastinal lymph nodes and ipsilateral pleural effusion are also considered LS- SCLC [51,52]. ES-SCLC includes disease that is not confined to a single radiation port, malignant pericardial effusion, contralateral pleural effusion, and distant hematogenous metastases [51,52]. The classification of contralateral supraclavicular or hilar lymph nodes is controversial. These nodes should be assessed on a case-by-case basis as to whether they may be feasibly included within a single radiation port [51,52].


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. In the combined TNM/VALSG approach for staging of SCLC, T1and T2 lesions and M1a ipsilateral pleural disease correspond with LS-SCLC. T3 and T4 lesions are conditional and may be LS or ES depending on the feasibility of inclusion within a single radiation port. Other M descriptors, including M1a contralateral pleural effusion, M1a pericardial effusion, M1b, and M1c comprise ES-SCLC [54]. CT Chest For patients with known or suspected SCLC, chest CT with IV contrast is recommended. If concurrent CT abdomen is not obtained, the adrenal glands should be covered. Chest CT without IV contrast may also be used. Chest CT is the modality of choice for initial evaluation of the SCLC. A large percentage of SCLCs arise from the central lobar or main bronchi. Consequently, the most common appearance of SCLC on imaging studies is a centrally located lung mass or mediastinal mass with hilar involvement [50]. In two-thirds of patients, tumor Noninvasive Clinical Staging of Primary Lung Cancer tissue encases mediastinal structures, including vessels, airways, and the esophagus [50]. Diagnosis of chest wall invasion on CT can be equivocal in cases of minimal invasion. Radiologic imaging cannot dependably detect visceral pleural invasion. Chest CT with IV contrast can aid in the identification of chest wall invasion by tumor, assessment of extent of mediastinal invasion, evaluation of additional mediastinal and hilar lymph nodes, distinction of central obstructing tumor from surrounding atelectasis, and assessment for liver metastases [50,51]. Unenhanced CT may be better able to characterize adrenal nodules. CT Abdomen and Pelvis CT abdomen and pelvis with oral and IV contrast is recommended in conjunction with CT chest to evaluate for extrathoracic metastasis in SCLC patients. Acquisition of arterial and portal venous phase sequences is advised. CT abdomen without IV contrast may also be obtained. Dual-phase imaging may be useful in this clinical setting.


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. Up to 60% of SCLC patients have metastases to the abdominal organs at presentation. The liver and adrenal gland are the most frequent site of hematogenous metastasis [55]. Traditionally, CT abdomen with IV contrast has been used to evaluate for extrathoracic metastases and distinguish between LS-SCLC and ES-SCLC. FDG-PET or PET/CT is increasingly used for this purpose and usually obviates the need for a separate CT abdomen and pelvis examination. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET or PET/CT is recommended in patients with clinical stage I or II LS-SCLC being considered for treatment with curative intent. FDG-PET or PET/CT for further staging is optional if ES-SCLC is established. FDG-PET has been shown on average to upstage the disease in up to 18% of patients with clinical LS-SCLC by conventional imaging. A meta-analysis of 7 prospective and retrospective trials found changes in management based on PET findings in 24% to 47% of SCLC patients [52,56,57]. A FDG-PET scan has superior sensitivity and specificity compared with CT in identification of metastatic disease other than brain metastases in SCLC patients [58-60]. Up to 60% of SCLC patients have metastases to the abdominal organs. The liver and adrenal gland are the most frequent site of hematogenous metastasis [55]. Although there is heterogeneous physiologic FDG activity in the liver, the accuracy of FDG-PET and PET/CT for liver metastases is reported at 92% to 100% [37]. When findings are discordant or indeterminate, MRI or biopsy are appropriate strategies to evaluate liver lesions. FDG-PET has sensitivity of 94% and specificity of 82% for characterization of adrenal nodules and is superior to CT alone. Lack of FDG uptake in an adrenal nodule is considered conclusive for benign adrenal adenoma and obviates further workup [31]. Patients with an FDG-avid adrenal nodule as the only site of potential metastatic disease require biopsy confirmation [51].


Noninvasive Clinical Staging of Primary Lung Cancer PCAs. The sensitivity, specificity, accuracy, and negative predictive value of FDG-PET for bone metastases is greater than 90% and is superior to bone scintigraphy [33,34]. MRI Brain MRI brain with IV contrast is recommended in all SCLC patients. MRI brain identifies metastatic lesions in 10% to 15% of newly diagnosed SCLC patients without neurologic symptoms. Up to 12% of patients with otherwise LS-SCLC have intracranial metastases on MRI [61]. MRI is more sensitive than CT for detection of intracranial metastases. MRI brain without IV contrast may be performed. CT Head CT head with IV contrast can be used as an alternate imaging modality in SCLC patients if brain MRI is not performed. Although MRI has greater sensitivity for small brain metastases, CT scanning of the brain is an appropriate method of evaluating for brain metastases in patients with SCLC [51]. Bone Scan Whole Body Tc-99m bone scintigraphy may be used as an alternate imaging modality to evaluate for extrathoracic bone metastasis in SCLC patients if FDG-PET or PET/CT is not performed. Bone metastases are present at the time of diagnosis in up to 37% of SCLCs and are a poor prognostic factor [62,63]. Historically, bone scintigraphy was indicated for the workup of all SCLC patients, but FDG-PET and PET/CT have largely replaced it [51]. Noninvasive Clinical Staging of Primary Lung Cancer MRI Chest MRI chest without and with IV contrast may be indicated in specific clinical circumstances in SCLC patients with equivocal findings on CT chest. Focused MRI of the chest may be useful in assessment of chest wall or spinal invasion and tumor involvement of mediastinal structures including the heart, great vessels, or pericardium. SCLC of the superior sulcus is less common than NSCLC [64] but requires MRI evaluation for locoregional disease affecting the brachial plexus [45]. MRI is superior to CT for detecting involvement of the neural foramina and spinal canal.


Hematuria

Hematuria.  Causes of hematuria can arise from anywhere along the urinary tract and are generally divided into nephrogenic and urogenic causes. Renal parenchymal disease is the most common benign nephrogenic cause of hematuria [1]. Common benign urogenic causes of hematuria include urolithiasis, infection, and benign prostatic hypertrophy [1]. Malignant causes can occur anywhere in the urinary tract and are the main entity that must be excluded during the imaging evaluation of hematuria. The most common factors associated with development of a urinary malignancy include gross hematuria, male gender, age >35 years, smoking, occupational exposure to chemicals, analgesic abuse, history of urologic disease, irritative voiding symptoms, history of pelvic irradiation, chronic urinary tract infection, exposure to known carcinogenic agents or chemotherapy, and chronic indwelling foreign body [1,2]. Gross hematuria has a high association with malignancy of up to 30% to 40%, and therefore all patients with gross hematuria should have a full urologic workup [1]. Conversely, patients with microhematuria have a low risk of malignancy ranging from 2.6% to 4%, and, in most patients with asymptomatic microhematuria, a cause is never found [1,2]. Patients without risk factors and with an identified benign cause of microhematuria including vigorous exercise, infection, trauma, menstruation, or recent urologic procedure are unlikely to gain any benefit from a complete imaging workup of microhematuria [1,2,5,6]. Patients with suspected urinary tract infection as a cause of microhematuria should have urine cultures performed, preferably before antibiotic therapy, to confirm an infection [1,2]. Patients with a suspected cause of microhematuria, including interstitial cystitis or benign prostatic hyperplasia, should have the appropriate clinical workup before undertaking imaging, including a pelvic examination in women, a rectal examination in men, and cystoscopy [1,2,6]. Interstitial cystitis, in particular, should


Hematuria

Hematuria. aJohns Hopkins University School of Medicine, Washington, District of Columbia. bNational Institutes of Health Clinical Center, Bethesda, Maryland. cPanel Chair, Northwestern University, Chicago, Illinois. dPanel Vice-Chair, UT Southwestern Medical Center, Dallas, Texas. eUniversity of Rochester Medical Center, Rochester, New York. fThe University of Texas MD Anderson Cancer Center, Houston, Texas. gUniversity of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, American Society of Nephrology. hUniversity of Washington, Seattle, Washington, American Urological Association. iDuke University Medical Center, Durham, North Carolina. jEmory University School of Medicine, Atlanta, Georgia. kThomas Jefferson University Hospital, Philadelphia, Pennsylvania. lCleveland Clinic, Cleveland, Ohio. mMedical University of South Carolina, Charleston, South Carolina, American Urological Association. nUniversity of Alabama at Birmingham Medical Center, Birmingham, Alabama. oUniversity of California San Francisco School of Medicine, San Francisco, California. pUniversity of Maryland School of Medicine, Baltimore, Maryland. qRhode Island Hospital/The Warren Alpert Medical School of Brown University, Providence, Rhode Island. rSpecialty Chair, University of Alabama at Birmingham, Birmingham, Alabama. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through society representation on expert panels. Participation by representatives from collaborating societies on the expert panel does not necessarily imply individual or society endorsement of the final document. Reprint requests to: publications@acr.org


Hematuria

Hematuria. Hematuria be considered in women with chronic pelvic pain along with microhematuria, because this diagnosis is prevalent but often difficult (glomerulonephritis, glomerulonephropathy, acute tubular necrosis, and acute kidney injury) should undergo a concurrent nephrology evaluation, but this should not preclude further evaluation of microhematuria [1,2]. Use of anticoagulant therapy does not alter the urologic evaluation of microhematuria [1,2]. Special Imaging Considerations CT urography (CTU) is an imaging study that is tailored to improve visualization of both the upper and lower urinary tracts. There is variability in the specific parameters, but it usually involves unenhanced images followed by intravenous (IV) contrast-enhanced images, including nephrographic and excretory phases, acquired at least 5 minutes after contrast injection. Alternatively, a split-bolus technique uses an initial loading dose of IV contrast and then obtains a combined nephrographic-excretory phase after a second IV contrast dose; some sites include arterial phase. CTU should use thin-slice acquisition. Reconstruction methods commonly include maximum intensity projection or 3-D volume rendering. For the purposes of this document, we make a distinction between CTU and CT abdomen and pelvis without and with IV contrast. CT abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts and without both the precontrast and excretory phases. MR urography (MRU) is also tailored to improve imaging of the urinary system. Unenhanced MRU relies upon heavily T2-weighted imaging of the intrinsic high signal intensity from urine for evaluation of the urinary tract. IV contrast is administered to provide additional information regarding obstruction, urothelial thickening, focal lesions, and stones. A contrast-enhanced T1-weighted series should include corticomedullary, nephrographic, and excretory phase.


Hematuria

Hematuria. Thin-slice acquisition and multiplanar imaging should be obtained. For the purposes of this document, we make a distinction between MRU and MRI abdomen and pelvis without and with IV contrast. MRI abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts, without both the precontrast and excretory phases, and without heavily T2-weighted images of the urinary tract. Discussion of Procedures by Variant Variant 1: Microhematuria. No risk factors, or history of recent vigorous exercise, or presence of infection, or viral illness, or present or recent menstruation. Initial imaging. Patients without risk factors and with a known benign cause of microhematuria are unlikely to gain any benefit from a complete imaging workup of microscopic hematuria. Multiple studies have shown that patients in this category do not derive any benefit from imaging [1,2,6,7]. Arteriography Kidney Arteriography is not used as a first-line imaging modality for the evaluation of microhematuria. There is no relevant literature regarding the use of arteriography for the initial evaluation of microhematuria. CT Abdomen and Pelvis For the purposes of this document, we make a distinction between CTU and CT abdomen and pelvis without and with IV contrast. CT abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts and without both the precontrast and excretory phases. CT without IV contrast may be a reasonable option in the setting of microhematuria in patients <50 years of age [8]. There is no relevant literature regarding the use of CT with IV contrast for the initial evaluation of microhematuria. CTU CTU CTU is not useful as a first-line imaging modality for the evaluation of microhematuria in patients with no known risk factors and with an identified benign cause of microhematuria.


Hematuria

Hematuria. Lisanti et al [7] found that in 442 patients <40 years of age and without risk factors, no patient had a malignancy-related hematuria finding at CTU. MRU MRU is not useful as a first-line imaging modality for the evaluation of microhematuria in patients with no known risk factors and with an identified benign cause of microhematuria. There is no relevant literature regarding the use of MRU for the initial evaluation of microhematuria. Hematuria MRI Abdomen and Pelvis For the purposes of this document, we make a distinction between MRU and MRI abdomen and pelvis without and with IV contrast. MRI abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts, without both the precontrast and excretory phases, and without heavily T2-weighted images of the urinary tract. There is no relevant literature regarding the use of MRI for the initial evaluation of microhematuria. Radiography Abdomen and Pelvis Conventional radiographs of the abdomen and pelvis (KUB) are not used as a first-line imaging modality for the evaluation of hematuria. There is no relevant literature regarding the use of radiography for the initial evaluation of microhematuria. Radiography Intravenous Urography IV urography (IVU) is no longer used as a first-line imaging modality for the evaluation of hematuria. There is no relevant literature regarding the use of IVU for the initial evaluation of microhematuria. US Kidneys and Bladder Retroperitoneal Ultrasound (US) is not useful as a first-line imaging modality for the evaluation of microhematuria with no known risk factors and with an identified benign cause of microhematuria. Variant 2: Microhematuria. Patients with risk factors, without any of the following: history of recent vigorous exercise, or presence of infection or viral illness, or present or recent menstruation, or renal parenchymal disease. Initial imaging.


Hematuria

Hematuria. Arteriography Kidney Arteriography is not used as a first-line imaging modality for the evaluation of microhematuria. There is no relevant literature regarding the use of arteriography for the initial evaluation of microhematuria. CT Abdomen and Pelvis For the purposes of this document, we make a distinction between CTU and CT abdomen and pelvis without and with IV contrast. CT abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts and without both the precontrast and excretory phases. There is no relevant literature regarding the use of CT with IV contrast or CT without IV contrast in this patient population with microhematuria. Initial studies compared CTU with other modalities but without direct comparison to conventional contrast-enhanced CT. However, in current practice, CTU has replaced conventional CT in this situation because of improved detection of urothelial lesions on CTU. CTU CTU CTU has been shown to be the imaging study of choice for the evaluation of microhematuria because it can evaluate both nephrogenic and urogenic causes of hematuria [1,2,9-12]. In a meta-analysis, CTU proved to be a very sensitive and specific method for the detection of urothelial malignancy with pooled sensitivity of 96% and pooled specificity of 99% and was superior in direct comparison to IVU in terms of sensitivity and specificity [10]. For the detection of upper tract lesions (kidneys and ureters), CTU has been shown to be superior to IVU with an accuracy of 99.6% compared with 84.9% for IVU [12]. CTU has also been shown to be useful for the detection of lower tract lesions (bladder) [11,13]. In one study of 242 patients with microhematuria, the specificity and accuracy of CTU for the detection of lower tract lesions was 98.8% and 97.2%, respectively [11]. In comparison with MRU, one study showed that CTU provided better visibility of the urothelial structures and improved diagnostic confidence [14].


Hematuria

Hematuria. MRU MRU has decreased spatial resolution compared with CTU. Also, small nonobstructive renal calculi and other calcifications as well as small urothelial lesions may be difficult to detect at MRU [15]. However, MRI has shown comparable accuracy to CT in the detection and characterization of renal masses [16]. Hematuria MRI Abdomen and Pelvis For the purposes of this document, we make a distinction between MRU and MRI abdomen and pelvis without and with IV contrast. MRI abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts, without both the precontrast and excretory phases, and without heavily T2-weighted images of the urinary tract. There is no relevant literature regarding the use of routine MRI with IV contrast in this patient population with microhematuria. Radiography Abdomen and Pelvis Conventional radiographs of the abdomen and pelvis (KUB) are not used as a first-line imaging modality for the evaluation of hematuria. There is no relevant literature regarding the use of radiographs for the initial evaluation of microhematuria. Radiography Intravenous Urography IVU is no longer used as a first-line imaging modality for the evaluation of hematuria. Multiple studies have shown that IVU has a low sensitivity for the detection of renal masses and urinary tract abnormalities in general compared with CT [9,10]. US Kidneys and Bladder Retroperitoneal US is not used as a first-line imaging modality for the evaluation of microhematuria. One study of 141 patients showed US had a lower sensitivity for the detection of urinary tract abnormalities compared with both CTU and MRU [17]. However, a recent large prospective study suggests that kidney and bladder US may be adequate for initial evaluation of microhematuria [18]. In this study, urinary cancer was diagnosed in 0.4% of patients who presented with microscopic hematuria, and all the patients had a renal carcinoma [18]. Variant 3: Microhematuria.


Hematuria

Hematuria. Pregnant patient. Initial imaging. Pregnant patients present with microhematuria at a rate similar to nonpregnant patients, and the rate of malignancy in this group is low [2,19]. Arteriography Kidney Arteriography is not used as a first-line imaging modality for the evaluation of microhematuria in pregnancy. There is no relevant literature regarding the use of arteriography for the initial evaluation of microhematuria. CT Abdomen and Pelvis CT is not used as a first-line imaging modality for the evaluation of microhematuria in pregnant patients secondary to the risks of radiation exposure to the fetus. The incidence of asymptomatic microhematuria in pregnant women is similar to nonpregnant women, and the rate of malignancy in this group is low [2]. CTU CTU is not used as a first-line imaging modality for the evaluation of microhematuria in pregnant patients secondary to the risks of radiation exposure to the fetus. The incidence of asymptomatic microhematuria in pregnant women is similar to nonpregnant women, and the rate of malignancy in this group is low [2]. MRU MRU MRU without and with IV contrast is not used as a first-line imaging modality for the evaluation of microhematuria in pregnant patients. The incidence of asymptomatic microhematuria in pregnant women is similar to nonpregnant women, and the rate of malignancy in this group is low [2]. MRU without IV contrast during pregnancy is a reasonable choice with a full workup after delivery once gynecologic bleeding and other benign causes (such as infection) have been excluded [2]. MRI with IV contrast should be avoided in pregnant patients because of uncertainty of effects of gadolinium contrast on the fetus. See the Safety Considerations in Pregnant Patients section below. MRI Abdomen and Pelvis The incidence of asymptomatic microhematuria in pregnant women is similar to nonpregnant women, and the rate of malignancy in this group is low [2].


Hematuria

Hematuria. MRI abdomen and pelvis with and without IV contrast is not used as a first- line imaging modality for the evaluation of microhematuria in pregnant patients. MRI abdomen and pelvis without IV contrast is not used as a first-line imaging modality because of the absence of heavily T2-weighted images of the urinary tract. Hematuria MRI with IV contrast should be avoided in pregnant patients because of the uncertainty of effects of gadolinium contrast on the fetus. See the Safety Considerations in Pregnant Patients section below. Radiography Abdomen and Pelvis Conventional radiographs of the abdomen and pelvis (KUB) are not used as a first-line imaging modality for the evaluation of hematuria in pregnancy. There is no relevant literature regarding the use of radiographs for the initial evaluation of microhematuria. Radiography Intravenous Urography IVU is not used as a first-line imaging modality for the evaluation of microhematuria in pregnancy. There is no relevant literature regarding the use of IVU for the initial evaluation of microhematuria. US Kidneys and Bladder Retroperitoneal The incidence of asymptomatic microhematuria in pregnant women is similar to nonpregnant women, and the rate of malignancy in this group is low [2]. US during pregnancy is a reasonable choice with a full workup after delivery once gynecologic bleeding and other benign causes (such as infection) have been excluded [2,19]. Variant 4: Gross hematuria. Initial imaging. Arteriography Kidney Arteriography is not used as a first-line imaging modality for the evaluation of gross hematuria. There is no relevant literature regarding the use of arteriography for the initial evaluation of gross hematuria. CT Abdomen and Pelvis For the purposes of this document, we make a distinction between CTU and CT abdomen and pelvis without and with IV contrast.


Hematuria

Hematuria. CT abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts and without both the precontrast and excretory phases. There is no relevant literature regarding the use of CT with IV contrast or CT without IV contrast in the evaluation of gross hematuria. CTU CTU The usefulness of CTU in the evaluation of gross hematuria has been mixed [11,13,20-23]. In one study of 150 patients, the sensitivity and specificity of CTU for the detection of bladder malignancy was 61.5% and 94.9% using cystoscopy as the reference standard [21]. However, in another study of 435 patients, CTU performed comparably to cystoscopy for the detection of bladder malignancy with sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 87%, 99%, 91%, and 98%, compared with 87%, 100%, 98%, and 98%, respectively, for cystoscopy [22]. The recent DETECT (Detecting Bladder Cancer Using the UroMark Test) 1 study recommends CTU for gross hematuria because of an upper tract tumor rate of 0.8% [18]. MRU There is no relevant literature regarding the use of MRU in patients with gross hematuria. Direct comparison of MRI and CTU sensitivity for evaluation of urothelial lesions in gross hematuria is not available in the literature. MRI Abdomen and Pelvis For the purposes of this document, we make a distinction between MRU and MRI abdomen and pelvis without and with IV contrast. MRI abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts, without both the precontrast and excretory phases, and without heavily T2-weighted images of the urinary tract. MRI without contrast may be helpful for the evaluation of gross hematuria. In one study of 130 patients, MRI had a sensitivity of 98.5% and PPV of 100% for determining the cause of gross hematuria, using cystoscopy and histopathology as the reference standards [24].


Chronic Dyspnea Noncardiovascular Origin.  Introduction/Background Dyspnea is the subjective experience of breathing discomfort [1], often described as a feeling of breathlessness, or shortness of breath. The perception of dyspnea derives from the interactions of physiological, psychological, environmental, and social factors that may provoke various physiologic and behavioral responses. Clinical history and physical examination may provide insight into the cause or causes of dyspnea; however, laboratory and ancillary tests are also often necessary. Overview of Imaging Modalities Radiography Chest The workup of chronic dyspnea is influenced by its severity, the rate of worsening, and the presence or absence of risk factors and other symptoms. The initial evaluation is aimed at determining whether the cause is related to cardiovascular disease, pulmonary disease, a combination of both, or neither. A chest radiograph will typically be performed in the initial workup. The results of the chest radiograph can help guide, and sometimes eliminate the need for, further investigation. Using an algorithmic approach, the combination of chest radiograph and laboratory evaluation may result in a specific diagnosis in one-third of cases [7]. CT Chest CT has an important role in the imaging evaluation of chronic dyspnea. It is useful when a radiographic abnormality requires further characterization or clinical findings necessitate additional imaging despite a normal radiograph [8,9]. For most routine applications, intravenous (IV) contrast is not needed, although it may be added when vascular abnormalities are in the differential diagnosis. CT protocols should be tailored to meet individual needs and may be determined based on radiographs and clinical features. For dyspnea, thin collimation of the lung parenchyma is essential. Most modern scanners allow this without additional data to be acquired.


Chronic Dyspnea Noncardiovascular Origin. Adjuncts, such as expiratory images, prone images, and dynamic imaging of the airways, may be applied in certain clinical situations; therefore, knowledge of the suspected diagnosis is essential for planning the CT scan. MRI Chest MRI does not currently have a significant role in the evaluation of chronic dyspnea that is not of cardiovascular origin. However, MRI may play a role in the workup of congenital anomalies and diseases of the Reprint requests to: publications@acr.org Chronic Dyspnea-Noncardiovascular Origin cardiopulmonary axis where both pulmonary imaging and cardiac imaging are desired in a single examination, and in the tissue characterization and assessment of extent of thoracic lesions. FDG-PET/CT Skull Base to Mid-Thigh Functional information from PET using the tracer fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)/CT can complement morphologic information derived from chest radiographs and CT. Attempts have been made to determine the efficacy of FDG-PET/CT in the behavior of inflammatory cells, extent of active lung disease, and response to therapy [10]. To date, evidence is limited to small series and has not been subjected to use in pharmacologic trials. US Chest Transthoracic ultrasound (US) imaging can be used for assessment of the lung periphery and pleura. Major advantages include portability, ease of use, and real-time imaging capability. US can target abnormalities and complement other imaging studies. It is particularly suited to bedside evaluation. Examples of uses in chronic dyspnea include the assessment of pleural and chest wall pathology, peripheral lung abnormalities, evaluation of diaphragmatic function, and guidance of interventional procedures. Discussion of Procedures by Variant Variant 1: Chronic dyspnea. Unclear etiology. Initial imaging. Radiography Chest The chest radiograph should generally be the initial imaging study in chronic dyspnea. Pratter et al [11] reported that it added sufficient information to justify its routine use.


Chronic Dyspnea Noncardiovascular Origin. In conjunction with cardiomyopathy, two-thirds of cases of chronic dyspnea in a pulmonary clinic were caused by asthma, COPD, and ILD. Pratter et al [7] later employed a prospective algorithmic approach to chronic dyspnea that used the chest radiograph as part of a Tier I evaluation. Karnani et al [2] advocated an algorithm that used the history and physical examination to guide appropriate testing, with the chest radiograph a component of a Level 1 diagnostic workup. Wahls [3] addressed the importance of the chest radiograph in the initial workup of chronic dyspnea in patients both with and without other physical examination findings. A chest radiograph might reveal a wide variety of abnormalities in chronic dyspnea that may guide further imaging choices as outlined in subsequent variants. Examples include COPD, ILD, central airways disease, and pleural, chest wall, and diaphragmatic pathology. CT Chest In cases where the chest radiograph is normal or does not provide a direct answer, CT can be beneficial for documenting abnormalities not identified on a chest radiograph and guiding further workup [8,12]. In the Multi- Ethnic Study of Atherosclerosis lung study, CT imaging for parenchymal disease was considered to be the most informative imaging test [13]. MRI Chest MRI has not been evaluated in a systematic manner for the assessment of patients with nonspecific chronic dyspnea, although it may have a role in specific clinical situations. US Chest Transthoracic US has good test characteristics for peripheral thoracic abnormalities, although it does not provide the comprehensive evaluation that CT does in the setting of an unspecified cause. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT has not been evaluated in a systematic manner for the assessment of patients with nonspecific chronic dyspnea, although it may have a role in specific clinical situations. Variant 2: Chronic dyspnea. Suspected chronic obstructive pulmonary disease (COPD). Initial imaging.


Chronic Dyspnea Noncardiovascular Origin. Radiography Chest In COPD, a radiograph can help exclude alternative diagnoses and evaluate for comorbidities and complications [14]. Wallace et al [15] reported that 14% of chest radiographs ordered during COPD evaluation detected potentially treatable causes of dyspnea other than COPD and lung cancer and that 84% of radiographs assisted management. Chronic Dyspnea-Noncardiovascular Origin CT Chest CT has greater sensitivity and specificity than a chest radiograph in determining the type, extent, and distribution of emphysema and bronchial wall abnormalities [16]. CT is able to identify early changes of COPD in asymptomatic and spirometrically normal smokers [17]. It has shown that visual assessments of emphysema and airway disease are accurate and reproducible [18]. In addition, quantitative CT-derived parameters correlate with pulmonary function tests and can be used as imaging biomarkers to follow disease progression [19-23]. Findings have been shown to correlate with patient-reported measures [24-26] and to predict health status in COPD [27]. CT-based phenotypes have prognostic value in predicting future hospitalization, symptomatic decline, and mortality [28,29]. Expiratory CT has been reported to reflect airflow limitation and correlates well with levels of dyspnea [30]. MRI Chest Numerous MRI techniques are available to evaluate COPD, including hyperpolarized helium, T1 oxygen- enhanced mapping, and equilibrium signal mapping [31-33]. While predominately the subject of research, small studies have shown good correlation with CT-derived measures and provide a rationale for the use of MRI when quantitative imaging measures are needed. US Chest US may have a role in defining pleural or diaphragmatic complications related to COPD, but there is no supporting evidence for its use as a diagnostic technique for this condition. FDG-PET/CT Skull Base to Mid-Thigh There are no primary data to support the use of FDG-PET/CT to diagnose or manage COPD.


Chronic Dyspnea Noncardiovascular Origin. Variant 3: Chronic dyspnea. Suspected central airways disease. Initial imaging. Radiography Chest Chest radiographs have the potential to identify conditions of the trachea, with accuracy dependent on the condition to be identified. Compared to CT, radiographs have an accuracy of 89% [34]. It should be noted that radiographic findings may be normal or nonspecific. In a single-institution retrospective study of tracheal neoplasms, <50% were directly detectable by a chest radiograph [35]. CT Chest Examples of airway conditions that may result in chronic dyspnea and can be accurately diagnosed by CT include stenoses, tumors, and end-expiratory airway collapse/tracheobronchomalacia, with strong correlations when compared with bronchoscopy [36,37]. For the last condition, expiratory images are required for diagnosis. Both dynamic airway imaging and static forced expiratory imaging are able to accurately characterize airway collapse when compared with bronchoscopy [38,39]. It has been shown that the degree of expiratory collapse is greater on dynamic studies compared to static forced expiratory images, although the clinical importance of this observation remains unclear [39,40]. Forced expiratory measurements show good reproducibility in healthy volunteers [41]. Volume acquisition of the airways allows for the production of 2-D and 3-D reformations that can better delineate the extent of abnormalities, while perspective volume rendering (virtual bronchoscopy) may be helpful in preprocedural planning. MRI Chest There are limited data supporting the use of MRI for the central airways in adult populations [42,43]. Some data supporting the use of MRI in pediatric populations [44,45] may be applicable in adults. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT has a supplemental role in the staging of tracheal neoplasms; however, there are no data to support its use in other tracheal conditions.


Chronic Dyspnea Noncardiovascular Origin. US Chest One small study has shown that measurements obtained from US imaging of the extrathoracic trachea correlate well with MRI [46]; however, a transthoracic US technique is limited by its inability to evaluate the entire tracheobronchial tree. Chronic Dyspnea-Noncardiovascular Origin Variant 4: Chronic dyspnea. Suspected interstitial lung disease. Initial imaging. Radiography Chest The chest radiograph may be abnormal in diffuse ILD; however, studies documenting the sensitivity of chest radiographs predate the widespread use of CT [47]. A normal chest radiograph in the setting of suspected ILD does not exclude the possibility of clinically important ILD. In subjects with diseases that predispose them to ILD (eg, connective tissue disease), it is reasonable to consider CT rather than radiography as the primary screening modality. CT Chest CT is currently the preferred imaging method for evaluating ILD [48]. CT protocols should be tailored to the clinical setting and may include expiratory or prone imaging. Good correlation has been reported between extent of disease on CT and severity of dyspnea [49-53]. CT findings are often sufficient to permit either a limited differential or confident diagnosis; the latter occurs particularly in the diagnosis of usual interstitial pneumonia [54-57], although the diagnostic yield improves with multidisciplinary discussion [58,59]. There is moderate agreement across individuals in the rating of honeycomb change [60]. The presence and extent of honeycomb change and other imaging features of ILD may serve as important prognostic variables [61,62]. MRI Chest MRI does not currently have an established clinical role in the evaluation of ILD, although small studies have shown good concordance with CT [63-65]. In general, MRI does not yet display the same level of parenchymal detail that is available with CT.


Chronic Dyspnea Noncardiovascular Origin. A specific advantage of MRI may exist when a single examination is desired for the evaluation of both ILD and its effect on the cardiovascular system [66]. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT may have a secondary role in ILD evaluation. It can be used as a marker of disease extent and severity in sarcoidosis [67], reveal inflammatory activity before morphological changes are demonstrated on CT [68], and assist in follow-up and the monitoring of treatment response [10]. Some studies show that the degree of FDG activity correlates with severity and prognosis in ILD [69-71]. US Chest US has been evaluated as a potential ILD screening tool in high-risk populations. In scleroderma, US was concordant with CT in 83% of patients and demonstrated high sensitivity [72]. It is being used in some centers to detect chronic ILD [73,74] and is emerging as a monitoring tool [75]. Variant 5: Chronic dyspnea. Suspected disease of the pleura or chest wall. Initial imaging. Radiography Chest Pleural effusion is often diagnosed by a chest radiograph, and volume can reasonably be estimated [76]. A radiograph is somewhat limited in its ability to determine the exact location of an abnormality, whether parenchymal, pleural, or extrapleural. A chest radiograph may reveal structural abnormalities of the sternum, ribs, and thoracic spine that may predispose toward dyspnea. CT Chest CT is superior to radiographs in detecting and characterizing pleural disease, differentiating it from parenchymal and chest wall disease, and determining the extent of involvement [77]. CT is somewhat limited in its ability to differentiate causes of pleural effusion, although the presence of pleural thickening or enhancement may help document complex exudative and malignant effusions [78,79]. MRI Chest MRI may provide improved characterization and assessment of the extent of pleural and chest wall abnormalities compared to CT.


Chronic Dyspnea Noncardiovascular Origin. MRI can help distinguish components of complex fluid collections, including septations [80], and is thought to be slightly better at distinguishing benign from malignant pleural thickening [81]. Improved soft-tissue contrast allows for better demonstration of soft-tissue relationships, which can facilitate the assessment of invasion and neurovascular encasement. Small studies have shown that MRI is capable of providing diagnostic images to guide surgical chest wall reconstruction [82]. There is extensive supportive literature in pediatric populations surrounding the detection and management of pectus excavatum. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT remains a secondary test that may be used in the staging of mesothelioma and pleural metastatic disease. Chronic Dyspnea-Noncardiovascular Origin US Chest US can complement the imaging evaluation of several abnormalities. US has an established role in pleural effusion, including detection, differentiation from lung disease, characterization, and guidance of intervention. US may be more efficacious than chest radiography and CT at detecting internal septations in complex pleural effusions [83]. Pleural thickening, plaques, and masses may be identifiable on US, although US is not recommended in their workup. US is advantageous in the bedside diagnosis of pneumothorax and is most often used in acute assessment [84]. Variant 6: Chronic dyspnea. Suspected diaphragm dysfunction. Initial imaging. Radiography Chest A static chest radiograph is useful to assess the relative position of the diaphragm and its effect on lung volumes and can provide clues to diaphragm paralysis compared to a fluoroscopic reference standard [85]. Fluoroscopy Chest With fluoroscopic visualization, more accurate assessment of diaphragmatic motion can be made [86,87].


Chronic Dyspnea Noncardiovascular Origin. CT Chest While CT can document the position of the diaphragm with multiplanar imaging and in theory can provide dynamic information, there are no data to support its use in the analysis of diaphragmatic dysfunction. MRI Chest Although not widely practiced, cine dynamic MRI sequences allow for the direct visualization of diaphragm motion [88]. This can result in comprehensive analysis of both the diaphragm and chest wall muscle movement in neuromuscular diseases [89]. US Chest US findings have been found to be concordant with fluoroscopic imaging of diaphragm motion, with reproducible results [90]. Diaphragmatic excursion amplitude, thickness, and contraction can be evaluated, and paralysis may be identified as paradoxical movement during respiration [91]. There is high sensitivity and specificity for the diagnosis of neuromuscular disorders of the diaphragm [92-95]. The extent of diaphragm motion in various conditions, including neuromuscular diseases, COPD, and ILD, correlates with respiratory symptoms and lung function [96-100]. Summary of Recommendations Variant 1: For patients with chronic dyspnea of unclear etiology, it is usually appropriate to initially evaluate with chest radiography, which may reveal a wide variety of abnormalities and guide further imaging decisions. Variant 2: The appropriate initial imaging study for patients with chronic dyspnea with suspected COPD is usually a chest radiograph, which can evaluate for comorbidities, complications, and alternative diagnoses. Variant 3: A chest radiograph is usually appropriate for the initial imaging of patients with chronic dyspnea and suspected central airways disease. Alternatively, CT without IV contrast is also usually appropriate, particularly for the detection of airway collapse, stenosis, or tumor. Variant 4: CT without IV contrast is usually appropriate for the initial imaging of patients with chronic dyspnea and suspected ILD, especially if the patient has a disease that predisposes to ILD.


Congenital or Acquired Heart Disease

Congenital or Acquired Heart Disease.  Introduction/Background Congenital and acquired pediatric heart disease is a large and diverse field with an overall prevalence estimated at 6 to 13 per 1,000 live births [1,2]. Congenital heart disease (CHD) can be broadly divided into acyanotic and cyanotic conditions. The 3 most common conditions are all acyanotic; bicuspid aortic valve, ventricular septal defects (VSD), and atrial septal defects. Common acquired cardiovascular conditions in children include aortopathy, cardiomyopathy, myocarditis, and vasculitis. Advanced imaging plays an important complementary role to transthoracic echocardiography (TTE) in the initial evaluation of congenital and acquired cardiovascular disease in children. Advances in treatment [2,3] have resulted in much longer survival of patients with CHD [4]. This longer survival has resulted in postsurgical patients often requiring imaging follow-up to look for secondary complications of corrective procedures like ventricular dysfunction, valvular dysfunction, and secondary vascular compromise. This document covers variants representing some of the most common indications for advanced imaging of childhood onset cardiovascular disease. All elements are essential: 1) timing, 2) reconstructions/reformats, and 3) 3-D renderings. Standard CTs with contrast also include timing issues and reconstructions/reformats. Only in CTA, however, is 3-D rendering a required element. This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization. Reprint requests to: publications@acr.org Congenital or Acquired Heart Disease


Congenital or Acquired Heart Disease

Congenital or Acquired Heart Disease. Arteriography Coronary with Ventriculography Catheter angiography is a useful modality for the evaluation of the coronary arteries and measurement of atrial and ventricular pressure. It provides direct measurements of RVOT gradients, dynamic assessment of regurgitant flow, and hemodynamic assessment of diastolic dysfunction [9]. Coronary angiography is performed in patients with suspected anomalous coronary artery to delineate the course of the coronary artery before interventions in the RVOT [10,11]. This could be important in the setting of percutaneous intervention, because one concern is coronary artery compression with inflation of a balloon-expandable stent in the RVOT when performing PVR percutaneously. Arteriography Pulmonary Cardiac catheterization is performed in patients only when alternative measures cannot accurately assess the RV and pulmonary artery anatomy or hemodynamics noninvasively. However, angiographic evaluation of PR severity is complicated by the fact that catheter position across the PV may influence the angiographic severity. It allows for simultaneous catheter-guided therapeutic interventions such as pulmonary artery balloon dilatation and stent placement and PVR [12]. CT Heart Function and Morphology A common deficiency of TTE imaging in repaired TOF is imaging of the branch pulmonary arteries. Multidetector CT provides accurate assessment of the anatomy of the branch pulmonary arteries, including within stented segments. It provides detailed anatomic evaluation of the heart and RVOT as well as other vascular abnormalities, such as pulmonary artery aneurysms or pseudoaneurysms, associated coronary anomalies, or aortic dilation [13,14]. Performing electrocardiogram (ECG) gating permits dynamic assessment of the RVOT for percutaneous pulmonary valve planning, and measurement of RV and left ventricular (LV) volume and function.


Congenital or Acquired Heart Disease

Congenital or Acquired Heart Disease. Multiplanar reformats allow for precise measurement of the cross-sectional area of the RVOT and valvular annulus, which are essential for selection of the appropriate prosthetic valve, and to screen for conduit calcification and kinking. before repeat surgery to replace the conduit or valve, CT is also helpful to determine safety of sternal re-entry. CTA Chest CTA without ECG gating or with prospective ECG gating may be used in the setting of TOF to avoid the need for sedation for morphological assessment of the branch pulmonary arteries, including within stented segments. It is also helpful to screen for right ventricle to pulmonary artery conduit calcification and stenosis and to determine safety of sternal re-entry before surgery. Congenital or Acquired Heart Disease CTA Coronary Arteries CTA technique can be used to study accurate coronary artery anatomy and exclude anomalous coronary artery crossing the RVOT before RVOT intervention or reoperation. Particularly, the relationship of the left or right coronary artery to the pulmonary outflow tract and pulmonary valve is important to assess because this may be compressed during percutaneous valve placement, conduit dilation, or sternal re-entry. FDG-PET/CT Heart There is no relevant literature to support the use of fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT heart in the evaluation of repaired TOF. MRA Abdomen There is no relevant literature to support the use of MR angiography (MRA) abdomen in the evaluation of repaired TOF. MRA Chest MRA of the chest is routinely performed along with MRI heart for function and morphology for delineation of the extracardiac vasculature, including the branch pulmonary arteries, aorta, and remaining mediastinal vasculature. MRA Neck There is no relevant literature to support the use of MRA neck in the evaluation of repaired TOF. MRI Heart Function with Stress There is no relevant literature to support the use of MR stress perfusion imaging in the setting of repaired TOF.


Congenital or Acquired Heart Disease

Congenital or Acquired Heart Disease. Radiography Chest The chest radiograph in TOF patients with severe PR often demonstrates increased cardiothoracic ratio on frontal view and retrosternal fullness on the lateral view due to cardiomegaly secondary to RV volume overload. The chest radiograph may also demonstrate dilated pulmonary trunk and may demonstrate dilatation of the ascending aorta [9]. In the posttreatment setting, radiography is essential to monitor location and integrity of stents in the pulmonary arteries, screen for RVOT pseudoaneurysm after conduit placement, and screen for asymmetry in the size and branching pattern of the parenchymal pulmonary arteries, which may indicate the presence of proximal vessel hypoplasia or stenosis. Perfusion Scan Lung The use of pulmonary perfusion scintigraphy allows for the assessment of differential pulmonary blood flow in patients with TOF and branch pulmonary artery stenosis or hypoplasia [12]. SPECT/CT MPI Rest and Stress Radionuclide angiography may be performed to assess LV function but has been replaced by MRI in this setting. Its use to assess RV function is limited by the confounding effect of counts from other chambers. In addition, its resolution is poor compared with other imaging methods and, therefore, has been of limited use in this setting. Congenital or Acquired Heart Disease US Echocardiography Transesophageal Transesophageal echocardiography (TEE) is considered a useful technique for intraoperative assessment of adequacy of outflow tract repair in terms of ruling out any residual obstruction or valve regurgitation as a consequence of surgery. TEE offers the advantages of permitting visualization of the operative procedure in real time and providing guidance for the surgeon [6,18] . The routine use of TEE during follow-up after surgery for patients with TOF is not established.


Congenital or Acquired Heart Disease

Congenital or Acquired Heart Disease. TEE is also useful in certain patients to guide interventional procedures or evaluate valve anatomy when transthoracic imaging is challenging, or when infectious endocarditis is suspected [12]. Variant 2: Child or adult. Transposition of the great arteries after atrial switch. Incomplete or inadequate assessment of cardiovascular morphology and function after transthoracic echocardiography. Next imaging study. Transposition of the great arteries (TGA) is a cardiac congenital defect characterized by discordant ventriculoarterial connections, in which the aorta arises above the morphological RV, and the pulmonary artery arises above the morphological LV. In TGA, the aorta usually is anterior to the PA, but it can be beside or behind the PA. The prevalence of TGA is 4.7 per 10,000 live births [19]. TGA accounts for 3% of all CHD and 20% of cyanotic heart disease. There are 2 major types of surgery performed for D-TGA: the atrial switch procedures (Mustard and Senning procedures) and the arterial switch procedures (Jatene procedure). In the atrial switch procedure, intra- atrial venous baffles redirect the systemic and pulmonary venous blood returns to the appropriate atria restoring circulating blood flow. These baffles are created by either using in situ tissue from the right atrial wall and interatrial septum (Senning procedure) or with autologous or synthetic material (Mustard procedure). Ventriculoseptal defects, if present, are also closed. Patients with Mustard or Senning type repair are now typically adult patients. The most common complications following the atrial switch procedures are intra-atrial venous baffle stenoses and leaks. Baffle stenoses typically occur at the superior limb of the baffle where the superior vena cava meets the right atrium. Baffle obstructions and leaks are estimated to occur in approximately 25% of patients [20]. The most important and relatively common postoperative complication is hypertrophy and decreased function of the systemic RV.


Congenital or Acquired Heart Disease

Congenital or Acquired Heart Disease. Less common complications include pulmonary arterial hypertension, residual VSD, subpulmonary stenosis, and arrhythmias. Arteriography Coronary with Ventriculography Since the coronary arteries are not surgically manipulated during an atrial switch procedure, there is no defined role for coronary arteriography in this setting. In patients with complex coronary anatomy in the setting of TGA, angiography may be helpful to demonstrate dynamic compression and angulation of the coronary arteries in patients with an interarterial course or in those with a muscular bridge [21], but this role has been superseded by CTA in most centers. Arteriography Pulmonary Pulmonary arteriography may be helpful if hemodynamic assessment of pulmonary artery pressure and resistance is required. Pulmonary arteriography is performed during interventions such as branch pulmonary artery balloon dilation and stent placement, to assess for baffle leaks, or narrowing of the systemic or pulmonary venous pathways [21]. CT Heart Function and Morphology CT is an alternative imaging modality to provide incremental information to echocardiography. CT functional assessment is a safer option to CMR in patients who are hemodynamically unstable. It is the most useful modality if anatomic restenosis is suspected in the setting of stents. CTA Chest CTA is the most useful modality if anatomic restenosis of pulmonary arteries is suspected in the setting of stents or presence of a metal susceptibility artifact that may hamper the use of MRA for this purpose. CTA Coronary Arteries Coronary CTA would be helpful when combined with cardiac CTA if repeat surgery is being considered given the increased rate of coronary anomalies. Congenital or Acquired Heart Disease FDG-PET/CT Heart There is no relevant literature to support the use of FDG-PET/CT heart in the evaluation of TGA after atrial switch. MRA Abdomen There is no relevant literature to support the use of MRA abdomen in the evaluation of TGA after atrial switch.


Congenital or Acquired Heart Disease

Congenital or Acquired Heart Disease. MRA Chest MRA chest provides important information regarding extracardiac structures such as the branch pulmonary arteries, systemic and pulmonary veins, and superior and inferior limb baffles and is used in conjunction with CMR for morphology and function to provide comprehensive evaluation of the cardiovascular system after treatment for TGA. MRA Neck There is no relevant literature to support the use of MRA neck in the evaluation of TGA after atrial switch. MRI Heart Function and Morphology CMR yields accurate and reproducible data regarding ventricular size and function, especially follow-up of systemic RV status and intracardiac baffles. MRI Heart Function with Stress CMR is a the most useful imaging modality to screen for myocardial ischemia, but this is uncommon after atrial switch for TGA because the coronary arteries are not manipulated during surgery. Radiography Chest Radiography of the chest can be used for preliminary assessment of stent position, pacemaker generator and lead position, and as needed during the course of follow-up. SPECT or SPECT/CT MPI Rest and Stress There is no relevant literature to support the use of single-photon emission CT (SPECT)/CT myocardial perfusion imaging (MPI) rest and stress in the evaluation of TGA after atrial switch. US Echocardiography Transesophageal TEE is useful in patients with poor transthoracic acoustic windows, during intraoperative imaging, and in patients (usually adolescents) who require cardioversion for arrhythmia. It is typically used to assess the adequacy of intraoperative repair TTE and may be more sensitive to detect baffle leaks and baffle obstruction. TEE is also helpful to guide catheter-based treatment of pathway obstruction such as balloon dilation, stent placement, or device closure of baffle leaks. Variant 3: Child or adult. Transposition of the great arteries after arterial switch. Incomplete or inadequate assessment of cardiovascular morphology and function after transthoracic echocardiography.


Congenital or Acquired Heart Disease

Congenital or Acquired Heart Disease. Next imaging study. The arterial switch operation (ASO) has superseded the Mustard and Senning procedures as the most common surgery performed in D-TGA. In the ASO (Jatene procedure), the ascending aorta and the main pulmonary artery are transected above their valve leaflets and moved to their correct circulatory position (Lecompte maneuver). The coronary arteries are then transplanted from the native aortic root to the neoaortic root (which is the native pulmonary trunk). Septal defects, if present, are surgically closed. Well-known sequelae after an ASO include obstruction of the coronary arteries with related myocardial ischemia, LV dysfunction, narrowing of the pulmonary artery side branches, RVOT obstruction, neoaortic valve insufficiency, and dilatation of the aortic root. RVOT and pulmonary artery stenoses may lead to RV dysfunction necessitating corrective procedures. Supravalvular pulmonary stenosis, particularly in the side branches of the pulmonary arteries, occurs early after an ASO. Dilatation and insufficiency of the neoaortic root usually develops over time. Coronary abnormalities can be present in 8% of asymptomatic individuals on 1- to 20-year follow-up and, although uncommon, can cause sudden death [23]. Noninvasive imaging of the postoperative anatomy is integral to the Congenital or Acquired Heart Disease management of patients who have undergone an ASO. A combination of imaging tests and exercise testing are performed to screen for complications and to assess severity and the need for intervention and the type of intervention. Arteriography Coronary with Ventriculography The coronary artery course has a particularly high variability in patients with TGA. After an ASO, many patients require repeated imaging of their reimplanted coronary arteries. Cardiac catheterization and ventriculography after ASO is reserved for only complex cases in whom incremental information is needed following advanced imaging.


Congenital or Acquired Heart Disease

Congenital or Acquired Heart Disease. Angiography is performed to assess for coronary artery stenosis after coronary artery reimplantation or during interventional procedures such as branch pulmonary artery balloon dilation and stent placement. In patients with complex coronary anatomy, angiography is useful in demonstrating dynamic compression and angulation of the coronary arteries in patients with an interarterial course or in those with a muscular bridge [21]. Arteriography Pulmonary Pulmonary arteriography is performed during interventions such as branch pulmonary artery balloon dilation and stent placement. CT Heart Function and Morphology CT is an alternative imaging modality to provide incremental information to echocardiography. CT functional assessment is more useful over CMR in patients who are hemodynamically unstable. It is the most useful modality if anatomic restenosis is suspected in the setting of stents. CTA Chest CTA of the chest is useful to study airway compromise, which may happen related to the aortic root or ascending aortic dilatation after ASO. A dynamic CTA may be helpful in this setting to distinguish intrinsic from extrinsic causes of airway obstruction. CTA is the most useful modality if anatomic restenosis of pulmonary arteries is suspected in the setting of stents or presence of a metal susceptibility artifact that may hamper the use of MRA for this purpose. CTA Coronary Arteries Obstructed coronary arteries occur in 8% of survivors and is a common cause of morbidity and mortality after the ASO [23]. ECG-triggered CTA is currently the most useful modality for the primary evaluation of coronary arteries. Its high spatial and temporal resolution allows for the reliable visualization of coronary arteries and screening for potential stenosis, usually without the use of sedation [19,24].