Chronic Hand and Wrist Pain

Chronic Hand and Wrist Pain. Some authors have advocated for the use of US as the confirmatory test of choice or as a complementary test for the suspected diagnosis of CTS due to the ability to identify space occupying lesions, anatomic variants including bifid median nerve and persistent median artery, and tendon pathology in the carpal tunnel and the false-positive rate of electrodiagnostic studies [70-73]. Despite evidence supporting the diagnostic capabilities of US in the setting of CTS, there is disagreement among hand surgeons regarding the necessity of diagnostic tests [73,74]. The 2016 American Academy of Orthopedic Surgeons guidelines reports limited evidence supports not routinely using US for the diagnosis of CTS [60]. Variant 6: Adult. Chronic hand or wrist pain. Radiographs normal or show nonspecific arthritis. Suspect tendon injury, tenosynovitis, or tendon pathology. Next imaging study. Bone Scan Area of Interest There is no relevant literature to support the use of bone scan in the setting of chronic hand and wrist pain with clinical concern for tendon injury, tenosynovitis, or tendon pathology. CT Area of Interest With IV Contrast There is no relevant literature to support the use of CT with IV contrast in the setting of chronic hand and wrist pain with clinical concern for tendon injury, tenosynovitis, or tendon pathology. CT Area of Interest Without and With IV Contrast There is no relevant literature to support the use of CT without and with IV contrast in the setting of chronic hand and wrist pain with clinical concern for tendon injury, tenosynovitis, or tendon pathology. CT Area of Interest Without IV Contrast There is no relevant literature to support the use of CT without IV contrast in the setting of chronic hand and wrist pain with clinical concern for tendon injury, tenosynovitis, or tendon pathology.


Chronic Hand and Wrist Pain

Chronic Hand and Wrist Pain. CT Arthrography Area of Interest There is no relevant literature to support the use of CT arthrography in the setting of chronic hand and wrist pain with clinical concern for tendon injury, tenosynovitis, or tendon pathology. MR Arthrography Area of Interest There is no relevant literature to support the use of MR arthrography in the setting of chronic hand and wrist pain with clinical concern for tendon injury, tenosynovitis, or tendon pathology. MRI Area of Interest Without and With IV Contrast The inclusion of postcontrast images to MRI of the wrist improves detection of tenosynovitis [43,75]. MRI Area of Interest Without IV Contrast The contrast resolution of MRI makes it ideal to assess soft tissue abnormalities in the hand and wrist. MRI of the hand or wrist without IV contrast can diagnose or confirm a multitude of tendon abnormalities including tendinopathy, tendon tear, intersection syndrome, tenosynovitis, stenosing tenosynovitis, pulley injuries, sagittal band, and palmar fibromatosis [13,43,76,77]. Radiographic Arthrography Area of Interest There is no relevant literature to support the use of MR arthrography in the setting of chronic hand and wrist pain with clinical concern for tendon injury, tenosynovitis, or tendon pathology. US Area of Interest Tendon injuries of the hand and wrist are well suited to US evaluation due to their superficial location and the ability to dynamically assess the tendons. US of the hand or wrist can diagnose or confirm a multitude of tendon abnormalities including tendinopathy, tendon tear, intersection syndrome, tenosynovitis, stenosing tenosynovitis, pulley injuries, sagittal band, and palmar fibromatosis [6,13,46,77,78]. US assists in operative and injection planning in patients with De Quervain tenosynovitis with accurate identification of an intracompartmental septum [79].


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs.  This document is specific to malignant or aggressive primary tumors of bone or soft tissue origin. This document specifically does not pertain to 1) metastatic disease to bone or soft tissues, 2) primary tumors of spine or neuroaxis origin, 3) primary tumors of head or neck origin, 4) intraabdominal or retroperitoneal tumors, 5) primary tumors of skin origin, and 6) plasma cell or other hematologic disorders that involve bone (ie, multiple myeloma). The variants in this document assume a diagnosis of a primary malignant or aggressive bone or soft tissue tumor has already been established. This document does not address the evaluation of chemotherapy or radiation therapy effectiveness or issues of cost-effectiveness and radiation dose. Special Imaging Considerations Hardware reconstruction is often needed following limb-sparing surgery for the management of bone tumors and occasionally for soft tissue tumors. This hardware creates artifact and limits evaluation of the adjacent structures with traditional CT, PET/CT, and MRI sequences and techniques. Although metal artifact can negatively impact CT, PET/CT, and/or MRI image quality, this document assumes metal artifact can be minimized with current metal artifact reduction protocols. There may still be instances where metal artifact cannot be sufficiently suppressed, and CT, PET/CT, and/or MRI become of limited benefit. In these cases, deviations from the variant recommendations may be necessary and should be informed by the clinical experience and expertise of the treatment team. aResearch Author, Mayo Clinic Florida, Jacksonville, Florida. bDiagnostic Imaging Associates, Chesterfield, Missouri. cPanel Chair, Mayo Clinic, Jacksonville, Florida. dPanel Vice-Chair, Wake Forest University School of Medicine, Winston Salem, North Carolina. eThe Johns Hopkins University School of Medicine, Baltimore, Maryland.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. fMallinckrodt Institute of Radiology Washington University School of Medicine, Saint Louis, Missouri. gNova Southeastern University, Fort Lauderdale, Florida. hMoffitt Cancer Center and University of South Florida Morsani College of Medicine, Tampa, Florida; MSK-RADS (Bone) Committee. iMayo Clinic Florida, Jacksonville, Florida. jStritch School of Medicine Loyola University Chicago, Maywood, Illinois; Commission on Radiation Oncology. kUniversity of Texas Health Science Center, Houston, Texas; American Academy of Orthopaedic Surgeons. lBrigham & Women's Hospital & Harvard Medical School, Boston, Massachusetts; American Association of Neurological Surgeons/Congress of Neurological Surgeons. mMayo Clinic Florida, Jacksonville, Florida, Primary care physician. nUniversity of Virginia, Charlottesville, Virginia. oSUNY Downstate Health Sciences University, Brooklyn, New York. pMayo Clinic, Jacksonville, Florida; Commission on Nuclear Medicine and Molecular Imaging. qSpecialty Chair, University of Kentucky, Lexington, Kentucky. 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 Discussion of Procedures by Variant Variant 1: Malignant or aggressive primary musculoskeletal tumor. Initial staging. Evaluation for pulmonary metastasis. Approximately 20% of patients with primary extremity sarcomas will have or develop distant metastatic disease. Pulmonary metastases account for approximately 75% of all sarcoma metastases, with variations of incidence depending on tumor histology and grade [4,5].


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. Metastatic disease decreases survival, with pulmonary metastases as the primary cause of death in patients with osteosarcoma [6,7]. Metastasectomy improves survival, and thermal ablation and radiation therapy are emerging as promising alternative treatment options [8-10]. Therefore, evaluation for pulmonary metastases is an essential part of primary musculoskeletal tumor initial staging. CT Chest With IV Contrast There is no relevant literature regarding the specific use of CT chest with intravenous (IV) contrast in the evaluation of pulmonary metastasis from malignant or aggressive primary musculoskeletal tumors. However, IV contrast may lead to equivocal assessment of mineralization, which can be a useful morphologic feature to distinguish benign versus malignant pulmonary nodules. Therefore, CT chest with IV contrast is not generally useful as the sole imaging technique, and there is felt to be little additional benefit in the CT assessment of pulmonary nodules without and with IV contrast compared with CT chest without IV contrast in this setting. CT Chest Without and With IV Contrast There is no relevant literature regarding the specific use of CT chest without and with IV contrast in the evaluation of pulmonary metastasis from malignant or aggressive primary musculoskeletal tumors. However, IV contrast may lead to equivocal assessment of mineralization, which can be a useful morphologic feature to distinguish benign versus malignant pulmonary nodules. Therefore, CT chest with IV contrast is not generally useful as the sole imaging technique, and there is felt to be little additional benefit in the CT assessment of pulmonary nodules without and with IV contrast compared with CT chest without IV contrast in this setting. CT Chest Without IV Contrast CT chest is the most sensitive imaging modality for identifying pulmonary nodules compared with radiography, fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT, or FDG-PET/MRI.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. However, studies have shown that even CT underestimates the number of pulmonary metastases compared with lung palpation during thoracotomy. Specific to osteosarcoma pulmonary metastases, CT missed approximately 10% of palpable lung lesions, of which nearly half were confirmed metastases in a series of 118 patients with osteosarcoma [9]. A smaller series of 28 patients with osteosarcoma also showed that CT missed 26% of viable metastases compared with palpation [11]. However, as CT technology improves and slice thickness decreases, more and smaller pulmonary nodules can be identified resulting in the dilemma of increased false-positive rates. A study of 283 lung nodules in patients with osteosarcoma found a statistically significant cutoff of 6 mm to differentiate benign and malignant pulmonary nodules (specificity 89.8%) [9]. A study of 311 subcentimeter pulmonary nodules in 195 patients with soft tissue sarcoma found combining morphologic criteria, in addition to size criteria, helped differentiate benign and malignant pulmonary nodules, with round solid nodules >5 mm more likely to be malignant (76% P = . 002) and complex ground-glass nodules <5 mm more likely to be benign (84%, P < . 0001) [12]. Given the survival benefit of treating pulmonary metastases, if pulmonary nodules are identified on any other modality in patients with primary musculoskeletal sarcoma, CT chest is then often indicated for biopsy and/or pretreatment planning. FDG-PET/CT Whole Body A meta-analysis of FDG-PET/CT for the staging of patients with osteosarcoma demonstrated 81% combined sensitivity and 94% specificity for detection of lung metastases [6]. The superiority of PET when combined with CT has been established [13].


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. Comparison studies between PET imaging alone versus CT acquired during FDG- PET/CT have been reported, although the CT acquired for attenuation correction and anatomic registration is not regarded as equivalent to dedicated diagnostic CT chest imaging [13]. Roberge et al [14] compared FDG-PET/CT with conventional imaging in a cohort of 109 patients during staging of extremity and body wall soft tissue sarcomas. In this cohort, 16 of the 109 patients had lung metastases, 10 of which were only identified on CT chest. Only 1 of the 16 patients with lung metastases was identified with FDG-PET/CT imaging but not CT chest. The authors concluded that FDG-PET/CT added little benefit over CT chest alone in evaluating for pulmonary metastasis [14]. A study comparing staging and follow-up imaging studies in 41 children with primary bone sarcomas showed greater sensitivity of CT chest (93%) versus FDG-PET/CT (80%) in detecting pulmonary metastases (although 4 Malignant or Aggressive Primary Musculoskeletal Tumor specificity was higher with FDG-PET/CT at 96% compared with 87% for CT chest). Of the false-negative FDG- PET/CT results in that study, half were pulmonary nodules <10 mm [15]. Evaluation of subcentimeter pulmonary nodules is a known limitation of FDG-PET/CT because of the inherent resolution constraints of PET/CT technology and respiratory motion artifact. However, a study of 63 lung nodules in 18 pediatric patients with bone sarcoma did demonstrate the value of using an FDG-PET standardized uptake value (SUV) cutoff in evaluating small pulmonary nodules; using an SUVmax >1 cutoff value and a nodule diameter cutoff of 6 mm can differentiate benign and malignant nodules with an accuracy of 92.1% compared with an accuracy of 88.9% with FDG-PET/CT visual analysis alone [16]. FDG-PET/MRI Whole Body Literature specific to sarcoma staging with FDG-PET/MRI is scarce.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. A single study by Platzek et al [17] in 2017 evaluated FDG-PET/MRI in sarcoma staging in 29 patients and compared results with conventional CT or MRI studies. Eight of the 29 patients had lung metastases, which were identified on both the FDG-PET/MRI and conventional imaging. However, the small sample size precludes application of this data to larger populations. The inherent decreased spatial resolution of MRI compared to CT raises doubts about the ability to identify small pulmonary metastases with FDG-PET/MRI as accurately as CT. MRI of the lungs relies heavily on the ability to minimize respiratory motion. Radiography Chest There is no relevant literature to support the use of chest radiography in the evaluation of pulmonary metastases in the initial staging of malignant or aggressive primary musculoskeletal tumors. Variant 2: Malignant or aggressive primary musculoskeletal tumor. Initial staging. Evaluation for extrapulmonary metastasis. The body regions covered in this clinical scenario are ankle, chest, shoulder, elbow, femur, foot, forearm, hand, humerus, knee, pelvis, tibia/fibula, and wrist. Bone Scan Whole Body Although historically Tc-99m bone scan has been used to detect bone metastasis, more recent studies have shown Tc-99m bone scan is inferior to FDG-PET/CT in the detection of bone metastases in general oncologic populations [23]. This conclusion has also been supported in patients with bone sarcoma. A study of 206 patients with stage IV osteosarcoma who underwent both Tc-99m bone scan and FDG-PET/CT calculated a 95% sensitivity and 98% accuracy for FDG-PET/CT versus 76% and 96%, respectively, for Tc-99m bone scan [24]. A smaller study of 64 pediatric patients with bone sarcoma also showed greater accuracy of FDG-PET/CT (84%) versus Tc-99m bone scan (70%) in detecting bone metastases during initial staging [22].


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. Other studies have suggested that this FDG- PET/CT superiority may be specific only to osteolytic metastases but not osteoblastic metastases [25-27]. The ability to detect extraosseous metastases that are usually occult on Tc-99m bone scan is an additional benefit of FDG-PET/CT [28]. Similarly, studies have demonstrated MRI whole body is superior to Tc-99m bone scan in detecting bone metastases in general populations. A study specific to patients with Ewing sarcoma of bone that had both MRI whole body and Tc-99m bone scan showed not only more bone metastases were identified with MRI, but 4 of the 71 patients had bone metastases only detected on MRI which changed the tumor stage for these patients [29]. Bone Scan Whole Body with SPECT or SPECT/CT Area of Interest The addition of single-photon emission computed tomography (SPECT) and SPECT/CT to Tc-99m bone scans can increase diagnostic confidence. A study of 2,954 Tc-99m bone scans in a general oncologic population increased diagnostic confidence by 75% and reduced equivocal findings by 27% [30]. However, there is no relevant literature 5 Malignant or Aggressive Primary Musculoskeletal Tumor to support the specific use of SPECT or SPECT/CT with bone scans in the initial staging for extrapulmonary metastasis of malignant or aggressive musculoskeletal tumors. CT Area of Interest With IV Contrast CT can be used to evaluate an area of interest identified clinically or from another imaging modality. There is no relevant literature to support the use of localized CT at an area of interest in the initial staging for extrapulmonary metastasis of malignant or aggressive musculoskeletal tumors; rather, a systemic approach to initial staging is recommended. CT Area of Interest Without and With IV Contrast CT can be used to evaluate an area of interest identified clinically or from another imaging modality.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. There is no relevant literature to support the use of localized CT at an area of interest in the initial staging for extrapulmonary metastasis of malignant or aggressive musculoskeletal tumors; rather, a systemic approach to initial staging is recommended. CT Area of Interest Without IV Contrast CT can be used to evaluate an area of interest identified clinically or from another imaging modality. There is no relevant literature to support the use of localized CT at an area of interest in the initial staging for extrapulmonary metastasis of malignant or aggressive musculoskeletal tumors; rather, a systemic approach to initial staging is recommended. FDG-PET/CT Whole Body A meta-analysis of FDG-PET/CT for the staging of patients with osteosarcoma demonstrated an overall sensitivity of 93% and a specificity of 97% for detection of bone metastases [6]. Coverage of a whole body FDG-PET/CT varies and usually extends either from skull base to thighs or skull vertex to feet. A study of FDG-PET/CT in patients with sarcoma and melanoma showed inclusion of the entire lower extremities does not add additional benefit in identifying metastases [31]. FDG-PET/CT is considered superior to Tc-99m bone scan in the detection of osseous metastases. Literature has concluded this in both general oncologic and bone sarcoma populations [30]. FDG-PET/CT is also superior to CT imaging in this regard. Quartuccio et al [22] studied 64 pediatric patients with bone sarcoma and found greater accuracy of FDG-PET/CT (85% accuracy) versus CT (44% accuracy) in detecting bone metastases during initial staging of patients with Ewing sarcoma. There are mixed conclusions when comparing FDG-PET/CT versus MRI whole body in detecting osseous metastases in general oncology populations [32-34]. In a small study of 20 patients with Ewing sarcoma comparing FDG-PET/CT with MRI whole body, a single patient had a false-positive bone finding on FDG-PET/CT.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. Overall, 39% more bone lesions in this study were identified with MRI whole body versus FDG-PET/CT [35]. In the Quartuccio et al [22] study of 64 pediatric patients with bone sarcoma, when FDG- PET/CT was compared with MRI for the detection of bone metastases, accuracy was similar (85% versus 89%). MRI better discriminates bone metastases from hematopoietic marrow, both of which can have increased metabolic activity on PET imaging. An advantage of PET over MRI is the ability to quantify tumor metabolic activity, which can serve as a prognostic indicator [15]. FDG-PET/CT can also be useful to detect nonskeletal metastases, more frequently in the lung, but also lymph nodes and other organs. FDG-PET/CT can detect a greater number of nodal metastases in soft tissue sarcoma versus conventional imaging alone [36,37]. The incidence of nodal metastases is dependent on tumor histology. FDG-PET/MRI Whole Body Literature specific to sarcoma staging with FDG-PET/MRI is scarce. A study of 29 patients with sarcoma who underwent FDG-PET/MRI and conventional imaging (CT chest/abdomen and/or local MRI) showed no significant difference in accuracy for detecting metastases with sensitivities and specificities of 97.8% and 100% for FDG- PET/MRI compared with 94.4% and 100% for conventional imaging. Of the 10 patients in this study with metastases, 6 had extrapulmonary metastases [17]. Another study of 98 bone lesions in a general oncologic population undergoing simultaneous FDG-PET/CT and FDG-PET/MRI showed these modalities to be equivalent for the detection and characterization of bone lesions [38]. Although FDG-PET/MRI whole body scans may prove to be useful in this setting, additional evidence is needed to compare its utility with existing modalities. Fluoride PET/CT Whole Body Fluoride PET/CT can increase diagnostic confidence when detecting bone metastases in general oncologic populations when compared with planar Tc-99m bone scans [39].


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. There is no relevant literature to specifically 6 Malignant or Aggressive Primary Musculoskeletal Tumor support the use of fluoride PET/CT in the initial staging for extrapulmonary metastasis of malignant or aggressive musculoskeletal tumors. Specifically, extraosseous extrapulmonary metastases will usually be occult on fluoride PET/CT whole body scans. MRI Whole Body Without and With IV Contrast There is no relevant literature to support the use of MRI whole body without and with IV contrast in the initial staging for extrapulmonary metastasis of malignant or aggressive musculoskeletal tumors. However, the addition of IV contrast can be helpful for assessing soft tissue masses and therefore could be beneficial in this setting. MRI Whole Body Without IV Contrast The ability of MRI to characterize soft tissue and bone marrow make it ideal for identifying extrapulmonary metastases. MRI is particularly useful in identifying and accurately characterizing bone marrow abnormalities as metastases versus nonmalignant processes. Hematopoietic marrow, or red marrow, is a frequently encountered nonmalignant marrow abnormality that can be mistaken for a metastasis on other modalities, particularly on PET imaging, when there is relatively increased metabolic activity. Hematopoietic marrow is abundant in the pediatric and young adult populations making it problematic for the staging of bone sarcomas in these populations. Multiple medications and other systemic illnesses can activate hematopoietic marrow in the adult population. Specific to myxoid liposarcoma, a sarcoma subtype known to metastasize preferentially to extrapulmonary locations, multiple studies have found MRI to be more accurate than FDG-PET, FDG-PET/CT, CT, radiography, and bone scintigraphy imaging to detect extrapulmonary metastases [40-44].


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. A small study in patients with Ewing sarcoma showed more bone lesions were more accurately identified on MRI whole body when compared with FDG-PET/CT [35]. There are mixed conclusions when comparing FDG-PET/CT versus MRI whole body in detecting osseous metastases in general oncology populations [32-34]. MRI whole body is more sensitive than Tc-99m bone scan for detecting osseous metastasis in a variety of tumors known to metastasize to bone. Sensitivity was also higher specifically in patients with Ewing sarcoma [29]. Radiography Area of Interest Radiographs could be used to evaluate an area of interest identified clinically or from another imaging modality. There is no relevant literature to support the use of radiography at an area of interest in the initial staging for extrapulmonary metastasis of malignant or aggressive musculoskeletal tumors. US Area of Interest There is no relevant literature to support the use of ultrasound (US) area of interest in the initial staging for extrapulmonary metastasis of malignant or aggressive musculoskeletal tumors. US could be used to evaluate an area of interest identified clinically or from another imaging modality. US is more useful to evaluate superficial soft tissue masses as opposed to bone lesions, which are usually occult if there is no cortical breakthrough. Variant 3: Malignant or aggressive primary musculoskeletal tumor with no suspected or known recurrence. Surveillance for pulmonary metastasis. Pulmonary metastases account for the majority of distant metastatic disease in patients with primary extremity sarcoma as a whole. Risk of pulmonary metastasis varies with tumor histology and grade. Although patients with high-grade soft tissue sarcomas develop lung metastasis at a rate of ~60%, those with low-grade sarcomas have lung metastasis rates <10% [45,46]. Therefore, guidance regarding modality for lung screening often differ between low-risk and high-risk patients.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. There is also debate concerning the frequency of lung surveillance. Given most pulmonary metastases will occur within 2 years of primary resection [47], many experts support more frequent surveillance initially in the first few years after diagnosis. Surveillance regimens usually de-escalate to annual follow-up after 5 years postresection [48-52]. Although these dynamic protocols are often used, a prospective randomized trial of 500 patients with resected extremity sarcomas and no baseline metastatic disease found no difference in overall survival or recurrence-free survival between groups whether surveilled at 3 month or 6-month consistent intervals [53,54]. Pulmonary metastases are associated with a worse prognosis [45], and treatment of these pulmonary metastases can improve survival [8,10]. Identification of pulmonary metastases is an essential part of primary musculoskeletal tumor screening. There is little to no variation in the ability of a certain modality to detect pulmonary metastasis whether performed at initial staging (see Variant 1), surveillance, or restaging in the setting of recurrence. 7 Malignant or Aggressive Primary Musculoskeletal Tumor CT Chest With IV Contrast There is no relevant literature regarding the specific use of CT chest with IV contrast in the evaluation of pulmonary metastasis from malignant or aggressive primary musculoskeletal tumors. However, IV contrast may lead to equivocal assessment of mineralization, which can be a useful morphologic feature to distinguish benign versus malignant pulmonary nodules. Therefore, CT chest with IV contrast is not generally useful as the sole imaging technique, and there is felt to be little additional benefit in the CT assessment of pulmonary nodules without and with IV contrast compared to CT chest without IV contrast in this setting.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. CT Chest Without and With IV Contrast There is no relevant literature regarding the specific use of CT chest without and with IV contrast in the evaluation of pulmonary metastasis from malignant or aggressive primary musculoskeletal tumors. However, IV contrast may lead to equivocal assessment of mineralization which can be a useful morphologic feature to distinguish benign versus malignant pulmonary nodules. Therefore, CT chest with IV contrast is not generally useful as the sole imaging technique, and there is felt to be little additional benefit in the CT assessment of pulmonary nodules without and with IV contrast compared to CT chest without IV contrast in this setting. CT Chest Without IV Contrast CT chest is the most sensitive imaging modality for the detection of pulmonary metastases. CT imaging for lung metastases has been criticized by some as being too sensitive. Several studies have attempted to find size and morphologic criteria to help discriminate between malignant and benign pulmonary nodules [9,12]. Rissing et al [55] showed that those only with pulmonary lesions <5 mm were associated with equivalent survival to those with normal scans. Often when a pulmonary metastasis is identified on a different imaging modality, CT is then required for biopsy or treatment planning. Guidance varies regarding whether to use CT chest versus chest radiography as surveillance for lung metastases in patients with sarcoma. Much of the debate also takes cost-analysis and radiation exposure into consideration. A retrospective study by Cho et al [56] of 176 patients with stage II or stage III high-grade extremity sarcomas calculated similar 5-year survival rates whether surveilled with chest radiography or CT chest. However, when stratifying survival rates by stage, they found a survival benefit for stage III patients when monitored with CT chest likely related to the increased rates of lung metastasis with high-grade sarcoma.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. Other studies have differing conclusions. A large multicenter retrospective study by Gamboa et al [45] comparing lung surveillance in 909 patients with extremity, truncal, or retroperitoneal high-grade soft tissue sarcomas found the 5-year survival rate was noninferior for patients followed with chest radiography versus CT chest (71% versus 60%). This study also found there was no difference in the rate or type of intervention for these lung metastases when detected. Selection bias was a limitation of both of these retrospective studies because the rationale of which modality used to screen was not known or reported. Additionally, the Gamboa et al [45] study included 151 patients with retroperitoneal sarcoma, which has a high rate of local recurrence; this group was overrepresented in the CT imaging group, which had the worse survival rate. A prospective randomized trial of 500 patients with resected extremity bone and soft tissue sarcomas without baseline metastases showed noninferiority of chest radiography compared with CT chest with similar overall survival (56% versus 53% respectively) and recurrence-free survival (59% versus 54% respectively) when used for lung surveillance [53,54]. FDG-PET/CT Whole Body Although FDG-PET/CT is not as sensitive for detecting pulmonary metastases as CT chest imaging, it has been shown to be more specific and therefore may be useful as a problem-solving tool when an indeterminate pulmonary nodule is detected on diagnostic chest CT. A study comparing staging and follow-up imaging studies in 41 children with primary bone sarcomas showed greater sensitivity of CT chest (93%) versus FDG-PET/CT (80%) in detecting pulmonary metastases (although specificity was higher with FDG-PET/CT at 96% compared with 87% for CT chest). Of the false-negative FDG-PET/CT results in that study, half were pulmonary nodules <10 mm [15].


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. Evaluation of subcentimeter pulmonary nodules is a known limitation of FDG-PET/CT because of the inherent resolution constraints of PET/CT technology and respiratory motion artifact. However, a study of 63 lung nodules in 18 pediatric patients with bone sarcoma did demonstrate the benefit of using an FDG-PET SUV cutoff in evaluating small pulmonary nodules; using an SUVmax >1 cutoff value and a nodule diameter cutoff of 6 mm can differentiate benign and malignant nodules with an accuracy of 92.1% compared with an accuracy of 88.9% with FDG-PET/CT visual analysis alone [16]. 8 Malignant or Aggressive Primary Musculoskeletal Tumor FDG-PET/MRI Whole Body There is no relevant literature to support the use of FDG-PET/MRI in the evaluation of pulmonary metastases during surveillance of malignant or aggressive primary musculoskeletal tumors. The inherent decreased spatial resolution of MRI compared with CT raises doubts about the ability to identify small pulmonary metastases with FDG- PET/MRI as accurately as CT. MRI of the lungs relies heavily on the ability to minimize respiratory motion. Radiography Chest Chest radiography is less sensitive than CT chest imaging for the detection of pulmonary nodules. Whooley et al [57] found that 83% of asymptomatic metastases were detected radiographically with a positive predictive value of 92% and a negative predictive value of 97%. However, the detection of more and smaller pulmonary metastases with CT versus radiography has definitely not improved survival rates. Although radiography is less sensitive for detection of lung metastases, how that correlates with clinically significant metastases is less certain. Variant 4: Malignant or aggressive primary bone tumor. Surveillance for local recurrence. The body regions covered in this clinical scenario are ankle, chest, elbow, shoulder, femur, foot, forearm, hand, humerus, knee, pelvis, tibia/fibula, and wrist.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. Local recurrence rates following primary resection of a malignant or aggressive bone tumor vary and depend on tumor grade and histology. Local recurrence rates of bone sarcomas are reported to be approximately 10% to 15% in patients with osteosarcoma and Ewing sarcoma [58-61]. Prognosis is poor for locally recurrent malignant or aggressive bone tumors, with postrecurrence 5-year survival rates reported approximately 15% to 30% in patients with osteosarcoma and 5% in patients with Ewing sarcoma [60,62]. Factors associated with poorer prognosis in patients with osteosarcoma were size of local recurrence (>5 cm) and presence of distant metastasis [60]. Recommendations for local recurrence surveillance imaging vary amongst expert guidelines, although all acknowledge the benefit of clinical evaluation. Locally recurrent bone tumors can often present as a soft tissue mass, and in a study of osteosarcoma local recurrences, the majority (approximately 75%) were soft tissue masses rather than bone lesions [60]. Some guidelines recommend clinical examination to be performed solely, whereas others recommend in combination with imaging [49,51,52,63]. Time to recurrence also varies with tumor histology. Most osteosarcoma local recurrences have been shown to occur within 5 years of resection. However, late recurrence of both osteosarcoma and Ewing sarcoma have been reported [60,61]. In a study of locally recurrent osteosarcoma, survival rates decreased from 30% at 5 years to 13% at 10 years, suggesting long-term follow-up beyond 5 years is beneficial. Tumor histology, grade, and clinical scenario remain paramount when deciding how to surveil for local recurrence. Bone Scan Whole Body Historically, bone scans have been used for the surveillance of local recurrence.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. Increased bone uptake at the primary resection site is nonspecific and can occur for many reasons, including stress changes from adjacent hardware, fractures, and possibly recurrence. With advances in MRI, CT, and PET imaging, the use of bone scan for local recurrence surveillance has decreased. Studies have shown superiority of FDG-PET/CT and MRI versus bone scan for assessment of bone metastases (see Variant 2). Although historically, Tc-99m bone scan has been used to detect bone metastasis, more recent studies have shown Tc-99m bone scan is inferior to FDG-PET/CT in the detection of bone metastases in general oncologic populations [23]. A smaller study of 64 pediatric patients with bone sarcoma also showed greater accuracy of FDG-PET/CT (84%) versus Tc-99m bone scan (70%) in detecting bone metastases during initial staging [22]. There is no relevant literature to support the use of bone scan whole body for surveillance of local recurrence of malignant or aggressive primary bone tumors. Bone Scan Whole Body with SPECT or SPECT/CT Area of Interest There is no relevant literature to support the use of bone scan whole body with SPECT or SPECT/CT area of interest for surveillance of local recurrence of malignant or aggressive primary bone tumors. CT Area of Interest With IV Contrast CT can be useful for surveillance of local recurrence when MRI is unable to be obtained. CT imaging can also be of benefit if metal artifact on MRI cannot be resolved, although it should be noted, CT is also susceptible to artifact from metal hardware. Although IV contrast does not provide added benefit for evaluation of bone, given many bone sarcoma recurrences present as soft tissue masses, IV contrast can be useful to increase the conspicuity of enhancing soft tissue tumors. 9 Malignant or Aggressive Primary Musculoskeletal Tumor


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. CT Area of Interest Without and With IV Contrast CT can be useful for surveillance of local recurrence when MRI is unable to be obtained. CT imaging can also be of benefit if metal artifact on MRI cannot be resolved, although it should be noted, CT is also susceptible to artifact from metal hardware. Although IV contrast does not provide added benefit for evaluation of bone, given many bone sarcoma recurrences present as soft tissue masses, IV contrast can be useful to increase the conspicuity of enhancing soft tissue tumors. However, given increased radiation dose without clinical benefit, CT without and with IV contrast is usually not recommended over CT with IV contrast alone. CT Area of Interest Without IV Contrast CT can be useful for surveillance of local recurrence when MRI is unable to be obtained. CT imaging can also be of benefit if metal artifact on MRI cannot be resolved, although it should be noted, CT is also susceptible to artifact from metal hardware. Although IV contrast does not provide added benefit for evaluation of bone, given many bone sarcoma recurrences present as soft tissue masses, IV contrast can be useful to increase the conspicuity of enhancing soft tissue tumors and is usually recommended in this setting. FDG-PET/MRI Whole Body There is no relevant literature to support the use of FDG-PET/MRI whole body as surveillance of local recurrence of malignant or aggressive primary bone tumors. Fluoride PET/CT Whole Body There is no relevant literature to support the use of fluoride PET/CT whole body as surveillance of local recurrence of malignant or aggressive primary bone tumors. MRI Area of Interest Without and With IV Contrast MRI of the primary tumor resection site has further asserted its usefulness for surveillance of local recurrence with improvements in metal artifact reduction.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. Given the preference for limb-sparing surgeries, many bone tumor resections require the implantation of hardware which creates local artifact that can obscure the adjacent tissues. Few studies comparing the use of MRI for local recurrence of bone tumors compared with other modalities have been published in recent years likely given its widespread adoption clinically. MRI is often requested before surgery and radiation when local recurrence is established. Given many local recurrences are soft tissue masses, the use of IV contrast remains beneficial to help characterize masses as malignant or benign and can also increase reader confidence [67,68]. MRI Area of Interest Without IV Contrast MRI of the primary tumor resection site has further asserted its usefulness for surveillance of local recurrence with improvements in metal artifact reduction. Given the preference for limb-sparing surgeries, many bone tumor resections require the implantation of hardware, which creates local artifact that can obscure the adjacent tissues. Few studies comparing the use of MRI for local recurrence of bone tumors compared with other modalities have been published in recent years likely given its widespread adoption clinically. MRI is often requested before surgery and radiation when local recurrence is established. Given many local recurrences are soft tissue masses, the use of IV contrast remains beneficial to help characterize masses as malignant or benign and can also increase reader confidence. However, the inherent contrast resolution of MRI, even in the absence of IV contrast, makes this a useful modality to assess for local recurrence of malignant or aggressive primary bone tumors [67,68]. 10 Malignant or Aggressive Primary Musculoskeletal Tumor Radiography Area of Interest Not only is radiography useful to evaluate for bone tumor recurrence, but it is also an invaluable adjunct to MRI interpretation.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. When hardware is present, even with modern metal-artifact reduction techniques, radiography can visualize the bone-metal or bone-cement interface, which can be critical to evaluate for tumor recurrence. Radiographs are recommended for the surveillance of local recurrence of malignant or aggressive primary bone tumors. US Area of Interest US is not useful for evaluating bone lesions when there is no extraosseous tumor extension. However, US may be beneficial if a mass is identified clinically. There is no relevant literature to support the use of US as surveillance for asymptomatic local recurrence of malignant or aggressive primary bone tumors. Variant 5: Malignant or aggressive primary soft tissue tumor. Surveillance for local recurrence. The body regions covered in this clinical scenario are abdomen, ankle, chest, elbow, shoulder, thigh, foot, forearm, hand, arm, knee, pelvis, leg, and wrist. Local recurrence rates of soft tissue sarcomas have been reported to occur at rates of 5% to 25% in larger historic studies [69-72]. Although rates of local recurrence following primary resection depend on tumor histology and grade, several other factors have been identified that increase risk. Tumor location is associated with local recurrence, with those tumors located deep to fascia or in the upper extremities/trunk as more likely to recur [73]. Positive or close resection margins have also been associated with increased likelihood of local recurrence [70,73,74]. Local recurrence is associated with metastatic disease and increased mortality [70], and if the recurrence can be treated before developing metastatic disease there is a survival benefit [73]. Size of the recurrence has also been linked with not only survival [75] but also morbidity, because larger tumors often require more extensive surgery [48]. Therefore, surveillance for local recurrence is important to reduce both mortality and morbidity.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. There remains some controversy not only on how to surveil resected soft tissue sarcomas but also if imaging surveillance is even necessary. The primary dispute against the need for imaging surveillance is the argument that recurrences are usually clinically detectable [54,76]. The literature also has some conflicting evidence on this topic. For example, a prospective study of 500 patients with sarcoma found 90% of local recurrences were clinically detected [54]. Conversely, a large recent study of 325 patients with soft tissue sarcomas found a rate of 60% of the local recurrences were not detected clinically [77]. Expert guidelines vary on recommendations for local recurrence imaging, although all acknowledge the benefit of clinical evaluation; some guidelines recommend clinical examination to be performed solely, whereas others recommend in combination with imaging [49,51,52,63]. Clinical evaluation of deep soft tissue local recurrence remains a limitation of this approach. Most local recurrences of soft tissue sarcomas occur within 5 years of primary resection [78]. Therefore, those guidelines that recommend imaging usually advocate for more aggressive imaging in the first 5 years that taper off to annual imaging. Tumor histology, grade, and clinical scenario remain paramount when deciding how to surveil for local recurrence. CT Area of Interest With IV Contrast CT remains useful for surveillance of local recurrence when MRI is unable to be obtained. CT imaging can also be of benefit if metal artifact on MRI cannot be resolved, although it should be noted CT is also susceptible to artifact from metal hardware. When evaluating the soft tissues, postcontrast imaging is recommended to increase the conspicuity of enhancing tumors and, if so, areas of necrosis that can help with biopsy planning and to serve as a baseline for future therapy response assessment.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. CT Area of Interest Without and With IV Contrast CT remains useful for surveillance of local recurrence when MRI is unable to be obtained. CT imaging can also be of benefit if metal artifact on MRI cannot be resolved, although it should be noted CT is also susceptible to artifact from metal hardware. When evaluating the soft tissues, postcontrast imaging is recommended to increase the conspicuity of enhancing tumors and, if so, areas of necrosis that can help with biopsy planning and to serve as a baseline for future therapy response assessment. However, CT without and with IV contrast is usually not recommended over CT with IV contrast alone. CT Area of Interest Without IV Contrast CT remains useful for surveillance of local recurrence when MRI is unable to be obtained. CT imaging can also be of benefit if metal artifact on MRI cannot be resolved, although it should be noted CT is also susceptible to artifact from metal hardware. When evaluating the soft tissues, postcontrast imaging is recommended to increase the 11 Malignant or Aggressive Primary Musculoskeletal Tumor conspicuity of enhancing tumors and, if so, areas of necrosis that can help with biopsy planning and to serve as a baseline for future therapy response assessment. FDG-PET/CT Whole Body FDG-PET/CT has the added benefit of not only thin-slice CT imaging but also the ability to detect metabolically active disease. FDG-PET/CT is highly accurate in detecting recurrent soft tissue and bone sarcomas, and may be useful as a problem-solving tool when other imaging of the area of interest is equivocal. A retrospective single- institution study of 43 patients with bone or soft tissue sarcomas found better sensitivity and specificity of FDG- PET/CT follow-up versus contrast-enhanced CT imaging (94% and 92% versus 78% and 67%, respectively) [79].


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. A retrospective single-institution study of 152 patients with soft tissue sarcomas comparing whole body FDG- PET/CT with MRI at the primary treatment site did not detect a significant difference in performance for detecting local recurrence (MRI sensitivity of 90% and specificity of 98%, compared with FDG-PET/CT sensitivity of 95% and specificity of 96%) [80]. FDG-PET/MRI Whole Body A retrospective single-institution study of 41 patients with resected soft tissue sarcomas and with clinically suspicious recurrence underwent FDG-PET/MRI, either whole body if a truncal primary or localized to the primary tumor site if an extremity sarcoma. The MRI portion and then FDG-PET/MRI portions were interpreted independently. With the addition of FDG-PET imaging to the MRI, sensitivity increased from 82% to 96%, although specificity mildly decreased from 85% to 79%. Diagnostic confidence increased for the readers [81]. FDG- PET/MRI whole body may be useful as a problem-solving tool when other imaging of the area of interest is equivocal. MRI Area of Interest Without and With IV Contrast MRI used as surveillance of the primary soft tissue tumor site is the mainstay for evaluating local recurrence. Few studies regarding the diagnostic utility of MRI for local recurrence of soft tissue sarcomas have been published in recent years, likely given its widespread adoption clinically. MRI is useful not only for asymptomatic surveillance but also if a clinical area of concern at the resection site develops. MRI is often requested before surgery and radiation when local recurrence is established. A retrospective single-institution study by Park et al [77] of 325 patients with extremity sarcoma with a local recurrence rate of 11% found MRI detected 60% of those patients with recurrence not identified clinically or with US. Those with MRI detected local recurrence trended towards better survival, but this did not reach statistical significance.


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. MRI has been criticized as having many false-positive results, leading to unnecessary procedures and emotional distress [82]. A retrospective single-institution study of 11 local recurrences in 124 patients with soft tissue sarcoma found MRI had a positive predictive value of only 42% with 11 false-positive examinations in this cohort and advocated for clinical surveillance only [83]. However, the Park et al [77] larger single-institution studies found a positive predictive value of 93%. Postcontrast imaging has been shown to add benefit in evaluation of soft tissue tumors to differentiate benign versus malignant lesions [68]. A more recent retrospective study assessing the added value of postcontrast MRI showed contrast improved reader confidence even for experienced readers and improved accuracy of a more inexperienced reader from 65% to 72% [67]. MRI Area of Interest Without IV Contrast MRI used as surveillance of the primary soft tissue tumor site is the mainstay for evaluating local recurrence. Few studies regarding the diagnostic utility of MRI for local recurrence of soft tissue sarcomas have been published in recent years, likely given its widespread adoption clinically. MRI is useful not only for asymptomatic surveillance but also if a clinical area of concern at the resection site develops. MRI is often requested before surgery and radiation when local recurrence is established. A retrospective single-institution study by Park et al [77] of 325 patients with extremity sarcoma with a local recurrence rate of 11% found MRI detected 60% of those patients with recurrence not identified clinically or with US. Those with MRI detected local recurrence trended towards better survival but this did not reach statistical significance. MRI has been criticized as having many false-positive results leading to unnecessary procedures and emotional distress [82].


Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. A retrospective single-institution study of 11 local recurrences in 124 patients with soft tissue sarcoma found MRI had a positive predictive value of only 42% with 11 false-positive examinations in this cohort and advocated for clinical surveillance only [83]. However, the Park et al [77] larger single-institution studies found a positive predictive value of 93%. 12 Malignant or Aggressive Primary Musculoskeletal Tumor Postcontrast imaging has been shown to add benefit in evaluation of soft tissue tumors to differentiate benign versus malignant lesions [68]. A more recent retrospective study assessing the added value of postcontrast MRI showed contrast improved reader confidence even for experienced readers and improved accuracy of a more inexperienced reader from 65% to 72% [67]. However, MRI without IV contrast is still highly sensitive in detecting local recurrence of soft tissue tumor because of an inherent soft tissue contrast of MRI and therefore is still of benefit. Radiography Area of Interest In rare instances of a primary soft tissue tumor that produces osseous or chondroid matrix, there may be limited benefit of radiography area of interest for detecting local recurrence, but in general this modality is usually not helpful for most patients. There is no relevant literature to support the use of radiography alone as surveillance for local recurrence of malignant or aggressive primary soft tissue tumors. US Area of Interest Local recurrence of a soft tissue tumor can be detected with US. Note that most studies comparing US with MRI are outdated because both US and MRI technology have advanced significantly.


Scoliosis Child

Scoliosis Child.  It should be noted that the diagnosis of idiopathic scoliosis is of exclusion. This includes exclusion of a variety of neuromuscular disorders commonly associated with scoliosis, such as cerebral palsy and muscular dystrophy. Intramedullary, extramedullary, and vertebral tumors can be associated with scoliosis, with osteoid osteoma of the posterior elements perhaps being the most well-known. Vertebral infections, such as tuberculosis, may also result in kyphoscoliosis [1,2]. Conditions with dysplastic skeletal development should also be clinically excluded, including osteogenesis imperfecta, neurofibromatosis type I, Marfan syndrome, Ehlers-Danlos syndrome, and achondroplasia. Clinical presentation and physical examination in idiopathic scoliosis are negative for cutaneous stigmata that suggest underlying spinal dysraphism (hemangioma, hairy patches, nevi, dermal appendages, or sinus tracts) [10]. When radiographs reveal anomalies of vertebral formation or segmentation, the scoliosis is termed congenital, accounting for up to 10% of surgical patients [2]. Neural axis anomalies, such as hydrosyringomyelia, Chiari malformation, and cord tethering, have been reported to occur in more than 20% of such patients who thus may benefit from routine preoperative MRI [11]. 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 MRI MRI of the spine, with its superior soft-tissue contrast is selectively used in the setting of scoliosis to detect and characterize suspected intraspinal abnormalities.


Scoliosis Child

Scoliosis Child. Intravenous (IV) gadolinium-based contrast agents are not routinely used in the setting of scoliosis, except in those instances when tumor or infection is a consideration. CT Multiplanar and 3-D reconstruction CT of the bony spine can help in selected cases for presurgical planning. In addition, the volumetric CT data can be used for surgical navigation [16,17]. CT may also be used to characterize and define the extent of the lesion, such as with the nidus of an osteoid osteoma. CT can be rapidly acquired, and low-dose protocols have been developed and implemented [18]. IV iodine-based contrast is almost never warranted in the perioperative setting, the exception being when tumor or infection is suspected and MRI with contrast cannot be obtained because of a contraindication. Bone Scan Tc-99m methyl diphosphonate (MDP) bone scintigraphy has been advocated in the specific setting of painful scoliosis and is particularly sensitive in cases with primary bone tumors, such as osteoid osteoma or osteoblastoma, spondylolysis, and infection. However, generalized pain is common in scoliosis, occurring in up to a third of idiopathic cases, and radiography often demonstrates the etiology in those individuals with an underlying bone abnormality [19]. Bone scintigraphy findings are usually not specific. Therefore, after initial evaluation with radiography, MRI is generally the second-line imaging modality even in the setting where a primary bone tumor, such as osteoid osteoma, is a consideration [20]. Discussion of Procedures by Variant Variant 1: Child. Congenital scoliosis. Initial imaging. The body regions covered in this clinical scenario are the cervical, thoracic, and lumbar spine. These body regions might be evaluated separately or in combination as guided by physical examination findings, patient history, and other available information, including prior imaging.


Scoliosis Child

Scoliosis Child. MRI Complete Spine Congenital scoliosis as a result of abnormal vertebral formation and segmentation has been shown to be associated with a high incidence of intraspinal anomalies, with a reported prevalence ranging from 20% to 58% [11]. Underlying anomalies include tethered cord, filar lipoma, syringohydromyelia, and diastematomyelia [11]. In a study of 76 patients, Belmont et al [11] noted a prevalence of intraspinal anomalies in 28% of patients with isolated hemivertebra and 21% of patients with more complex vertebral anomalies. Interestingly, history and physical examination only demonstrated an accuracy of 62% for diagnosing an intraspinal anomaly with a hemivertebra. Shen et al [24], in a study of 226 Chinese surgical cases for congenital scoliosis, found a 43% incidence of intraspinal anomalies, the most common being diastematomyelia. Again, similar to the study by Belmont et al, a negative neurologic examination did not predict a normal MRI examination. MRI was suggested in both of these studies for the complete evaluation of congenital scoliosis. CT Spine CT may play a role in the initial imaging evaluation of congenital scoliosis. Multiplanar and 3-D volume rendered reformatted images derived from the axially acquired data set provide multiple views of the spine, allowing a perspective not readily available with conventional radiographs [25,26]. CT may specifically aid in the visualization and characterization of the osseous septum in type I split cord malformations [27]. CT is also helpful in presurgical planning for congenital scoliosis, facilitating visualization of the bony malformations and reducing instrumentation-related complications. Wu et al [26] reported a reduction in the rate of screw misplacement using CT-assisted planning, 6.5% as compared to 15.3% when using C-arm alone. Bone Scan Complete Spine Tc-99m MDP is not a primary imaging modality in the setting of congenital scoliosis as it provides no intraspinal information. Variant 2: Child (0 to 9 years of age).


Scoliosis Child

Scoliosis Child. Early onset idiopathic scoliosis. Initial imaging. The body regions covered in this clinical scenario are the cervical, thoracic, and lumbar spine. These body regions might be evaluated separately or in combination as guided by physical examination findings, patient history, and other available information, including prior imaging. MRI Complete Spine Juvenile idiopathic scoliosis carries higher risk for intraspinal anomalies as compared with adolescent idiopathic scoliosis with a range of 13% to 27% [28-30]. Some suggest selective MRI for curve progression, neurologic status change, or routinely when surgical intervention is planned [30], or presurgically when there is back pain [9]. Other authors recommend total spine MRI for all patients with juvenile idiopathic scoliosis [28]. CT Spine CT does not play a significant role in the initial diagnostic assessment of early onset idiopathic scoliosis as it is limited with respect to intraspinal assessment. Bone Scan Complete Spine Tc-99m MDP is not a primary imaging modality in the setting of early onset idiopathic scoliosis as it provides no intraspinal information. Variant 3: Adolescent (10 to 17 years of age). Adolescent idiopathic scoliosis. No risk factors. Initial imaging. The body regions covered in this clinical scenario are the cervical, thoracic, and lumbar spine. These body regions might be evaluated separately or in combination as guided by physical examination findings, patient history, and other available information, including prior imaging. Surgical decision making and planning is also influenced by the flexibility of the curves, which can be assessed using a variety of radiographic techniques, such as side bending, push prone, fulcrum bending, and traction radiographs [33-37]. Cheh et al [38] found that a single supine spine radiograph can predict curve type, flexibility, and structurality.


Scoliosis Child

Scoliosis Child. SOSORT suggests limiting spine radiographs to once every 12 months for adolescent patients at Risser stages 0 to 3 and every 18 months for patients at Risser stages 4 to 5 unless there are objective clinical changes in the appearance of the scoliosis [39]. CT Spine CT of the spine in adolescent idiopathic scoliosis is not routinely used in initial diagnostic assessment. Rather, some orthopedists use perioperative CT for presurgical planning and intraoperative navigation to optimize screw placement [16,17,40,41]. Bone Scan Complete Spine Tc-99m MDP is not a primary imaging modality in the setting of adolescent idiopathic scoliosis as it provides no intraspinal information. Variant 4: Adolescent (10 to 17 years of age). Adolescent idiopathic scoliosis. Risk factors. Initial imaging. The body regions covered in this clinical scenario are the cervical, thoracic, and lumbar spine. These body regions might be evaluated separately or in combination as guided by physical examination findings, patient history, and other available information, including prior imaging. Surgical decision making and planning is also influenced by the flexibility of the curves, which can be assessed using a variety of radiographic techniques, such as side bending, push prone, fulcrum bending, and traction radiographs [33-37]. Cheh et al [38] noted that a single supine spine radiograph can predict nonstructural minor curves as well. SOSORT suggests limiting spine radiographs to once every 12 months for those adolescent patients at Risser stages 0 to 3 and every 18 months for patients at Risser stages 4 to 5, unless there are objective clinical changes in the appearance of the scoliosis [39]. MRI Complete Spine Up to 2% to 4% of adolescents with scoliosis have an intrinsic anomaly of their spinal cord or spinal contents that can only be identified with MRI [4,5]. The most common abnormalities revealed by MRI include Chiari I malformation, cord syrinx, cord tethering, and, more rarely, intrinsic spinal cord tumor [4,6].


Palpable Abdominal Mass Suspected Neoplasm.  Discussion of Procedures by Variant Variant 1: Palpable abdominal mass. Suspected intra-abdominal neoplasm. Initial imaging. Little has been written about the use of imaging in evaluating palpable abdominal masses since the 1980s. Newer reviews and case reports have focused on evaluation of specific masses using CT, ultrasound (US), and MRI. Radiography of the abdomen and fluoroscopy play a limited role in the diagnosis and workup of a palpable intra-abdominal mass. CT Abdomen There have been no recent studies on the diagnostic yield of CT for abdominal masses; however, it is widely used and assumed to be accurate in patients presenting with varying pathologies that may cause an abdominal mass [4- 7]. Most data on diagnostic accuracy stem from studies that are >30 years old. In a controlled trial from 1981 by Dixon et al [8], CT established diagnosis more quickly and reduced inpatient workup times in patients with abdominal masses when compared against conventional radiography and workup. In another study from 1984 by Williams et al [9], CT demonstrated high positive predictive value (99%) and negative predictive value (97%) for determining the presence or absence of a mass and correctly identified the organ of origin in 93% of patients with palpable abnormalities on clinical examination. The Dixon et al [8] study demonstrated that, compared with strategies not using CT, the use of CT can result in savings in time for diagnosis. Accordingly, when US findings are indeterminate, CT imaging should be obtained in a timely manner. Organomegaly (ie, enlargement of the liver, spleen, or kidneys), may present with a palpable mass. The differential diagnosis is lengthy, including lymphoma, primary organ disease, metastatic disease, extramedullary hematopoiesis, granulomatous disease, and infections. CT can provide clues to help narrow the differential aPanel Vice-Chair, Mallinckrodt Institute of Radiology, Saint Louis, Missouri.


Palpable Abdominal Mass Suspected Neoplasm. bVirginia Tech Carilion School of Medicine, Roanoke, Virginia. cPanel Chair, University of Wisconsin Hospital & Clinics, Madison, Wisconsin. dUniversity of Texas Health Science Center at Houston and McGovern Medical School, Houston, Texas; American Gastroenterological Association. eNewton-Wellesley Hospital, Newton, Massachusetts. fThe University of Texas MD Anderson Cancer Center, Houston, Texas; American College of Surgeons. gH. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida. hMassachusetts General Hospital, Boston, Massachusetts. iMedstar Georgetown University Hospital, Washington, District of Columbia. jCleveland Clinic, Cleveland, Ohio. kDuke University Medical Center, Durham, North Carolina. lEmory University, Atlanta, Georgia. mPenn State Health, Hershey, Pennsylvania. nUniversity of Alabama at Birmingham, Birmingham, Alabama. oBeth Israel Deaconess Medical Center, Boston, Massachusetts. pSpecialty Chair, Virginia Commonwealth University Medical Center, Richmond, Virginia. 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 Palpable Abdominal Mass-Suspected Neoplasm diagnosis, although biopsy is often warranted [6,10]. CT is considered safe and effective for guiding percutaneous biopsies if the pathology can be visualized and the operator has knowledge of technical parameters, such as the need for breath holding, triangulation methods, gantry angling, and appropriate patient positioning [11-13]. There are no recent studies that specifically address the question of whether CT should be performed with or without intravenous (IV) contrast for a palpable mass.


Palpable Abdominal Mass Suspected Neoplasm. Acquisition of CT both with and without contrast does not generally add diagnostic value. Although available evidence and experience generally supports the appropriateness of CT with IV contrast over that of noncontrast CT for evaluation of intra-abdominal organs and pathology [12,14,15], the use of noncontrast CT may be of value in some circumstances. US Abdomen US has many positive attributes and is a useful tool for detecting and diagnosing potential intra-abdominal masses [4-6,16-19]. In a retrospective study including 104 patients with palpable masses referred for US evaluation, 69 had a correlative mass and US correctly identified the organ of origin in 88% of patients [17]. The 3 cases where the organ of origin was not positively identified were all masses arising in the pelvis (endometriosis, uterine fibroids, and ovarian tumor), which were later defined on CT. Despite the failure in these cases, the positive predictive value was 99% and negative predictive value 97% for identifying or excluding a mass. The one false- negative case was a patient with palpable mass on examination who had a negative US but subsequently positive CT demonstrating transverse colon cancer. The accuracy for identifying the organ of origin ranges from 88% to 91%, and 77% to 81% for correctly suggesting the underlying pathology [16,17,20,21]. Although highly accurate, US visibility of the abdominal cavity may be limited because of bowel gas and body habitus. On the other hand, US has the benefit of real-time imaging. This can be very advantageous in the setting of palpable abnormality, providing additional information, such as tenderness, direct correlation, and dynamic changes like Valsalva maneuvers, when assessing for hernias. Studies have suggested that portable US units may improve diagnostic accuracy for detecting organomegaly [22] and may help to determine the need for additional diagnostic testing with a sensitivity of 91% and specificity of 83% [23].


Palpable Abdominal Mass Suspected Neoplasm. US is considered highly useful for real- time guidance for biopsy and establishing definitive diagnosis [11,12]. MRI Abdomen No comparative studies are available in the literature; however, there are several potential advantages to MRI that may advocate for its use in some instances. MRI possesses very high soft-tissue contrast, allowing depiction and differentiation of cystic structures, soft-tissue components, fat, and blood products [10]. This can be especially useful for defining benign from malignant lesions in organs such as the adrenal glands, kidneys, ovaries, and liver. Although MRI offers potential advantages, its exact performance in evaluating palpable masses relative to US and CT remains unclear given the absence of data; however, it is likely at least comparable. Although not always a first-line option, MRI can be very useful as a second-line imaging modality to further evaluate indeterminate masses detected on CT or US. Similar to CT, there is no evidence evaluating the utility and added benefit of IV contrast versus noncontrast MRI in the setting of a palpable intra-abdominal mass. Experience and evidence related to solid organ evaluation (liver, pancreas, and kidneys) suggests that IV contrast improves visualization of normal organs and pathology. However, there is some value in noncontrast MRI as it may still depict soft-tissue structures and delineate a mass. Radiography Abdomen Radiography is often not sufficient as a first step in evaluation of a palpable mass and hence the acquisition of cross-sectional imaging would likely be required for diagnosis regardless of the results of the radiograph [24,25]. Radiography may also be considered as a first step in rare situations. If the patient reports constipation, a radiograph could be used to confirm that diagnosis or to offer alternative diagnosis, such as bowel obstruction [26,27].


Palpable Abdominal Mass Suspected Neoplasm. Fluoroscopy Procedures (Contrast Enema, Upper GI Series, Small-Bowel Follow-Through) Fluoroscopy studies, such as contrast enema, upper gastrointestinal (GI) series, and small-bowel follow-through (SBFT), are usually not first-line imaging studies for palpable masses in adults. However, they may be used to further characterize associated degree of obstruction or abnormalities in GI function or transit [28]. As extraluminal findings are commonly not evaluated by contrast enema or upper GI series, additional imaging may be required even if an intraluminal mass is detected. Palpable Abdominal Mass-Suspected Neoplasm FDG-PET/CT Skull Base to Mid-Thigh In the absence of a known diagnosis, there is a very limited role for fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT in patients with palpable abnormalities. There is no literature to support its use as an initial imaging modality. The main role of FDG-PET/CT would be to stage a known neoplasm, potentially presenting with a new palpable abnormality. Variant 2: Palpable abdominal mass. Suspected abdominal wall mass. Initial imaging. The annual incidence of benign soft-tissue masses is approximately 3,000 per million population [29]. The rate of malignancy ranges from 5% to 42% in large series [30,31]. Clinical evaluation and history are important for developing a differential diagnosis, with features of large size, location within the abdominal cavity, growth, and recurrence at an excision site in a patient with a history of malignancy all raising suspicion of malignancy [31]. Imaging often plays a central role in further narrowing the differential diagnosis and guiding management. However, similar to Variant 1, there are few recent studies, and the overall quality of the literature is poor and primarily focused on specific disease processes rather than a diagnostic approach to palpable masses [32-36].


Palpable Abdominal Mass Suspected Neoplasm. The differential diagnosis related to the abdominal wall includes soft-tissue neoplasms of the skin, muscle, fat, bone, and vasculature. Additionally, hernias, congenital abnormalities, hematomas, and infections may present as abdominal wall masses. Differentiation of tissue components, such as blood products, fat, and vascularity, is important for narrowing the differential diagnosis and defining the relationship of the mass to tissue planes and structures is imperative in guiding management. US Abdomen Although no recent studies have evaluated the diagnostic accuracy of US specifically for abdominal wall masses, it is typically considered a first-line imaging modality [29,30,32]. This is due to the many advantages of US, such as capability of real-time imaging, Doppler evaluation of blood flow, and ability to assess for clinical features, such as tenderness. US can sometimes depict classic features of benign lesions, such as lipomas, desmoid tumors, vascular malformations, rectus sheath hematomas, infections, pseudoaneurysms, and endometriosis [30,32-34,36- 38]. However, in the setting of solid lesions, further workup and potentially tissue sampling is often needed. Although perhaps not widely used as a first-line imaging option, US can also confirm the presence of malignant masses, such as metastatic disease, sarcomas, and lymphomas. In a prospective study of 358 patients presenting with soft-tissue masses, US was performed as an initial imaging modality, yielding effective triage results with 100% specificity in referring indeterminate or potentially malignant masses on to more definitive imaging (MRI) and subsequent workup [31]. In patients with suspected abdominal wall endometriosis, which presents as a mass in many instances, US correctly detected disease in approximately 97% of cases in a retrospective series of 151 patients evaluated surgically [36].


Palpable Abdominal Mass Suspected Neoplasm. In a systematic review of the literature on abdominal wall endometriosis, the authors concluded that the overall quality of evidence is poor with no prospective studies; however, US or MRI can assist with localization and aid in surgical planning [39]. US has several limitations. It can be less specific than other imaging modalities for characterizing masses [31]. US visibility of the abdominal wall is usually possible with few limitations. However, US may not provide details of deeper structures and relationship of masses to anatomic fascial planes. US also has advantages; it has the benefit of real-time imaging, such as assessing dynamic changes like Valsalva maneuvers, when evaluating for hernias. US is considered highly useful for real-time guidance for biopsy, but percutaneous biopsy should be considered carefully and in conjunction with oncologic specialist when a sarcoma is suspected [30]. MRI Abdomen There is little recent literature on the diagnostic accuracy of MRI for abdominal wall mass evaluation. MRI acquired without and with IV contrast is recognized as a useful modality to further narrow the differential diagnosis of detected masses, because of its high soft-tissue contrast resolution, ability to differentiate fat and enhancement within structures, and sequences that identify iron and blood products that may aid in differential considerations, such as endometriosis or extramedullary hematopoiesis [10,35]. MRI acquired without and with IV contrast can depict specific imaging features for many entities, including endometriosis, simple lipomas, epidermoid cysts, desmoid tumors, and hematomas [38]. MRI acquired without IV contrast may also still depict soft-tissue structures and define anatomy/pathology. MRI may be a useful second-line examination, often recommended if a malignant or indeterminate mass is detected on US [29,30]. In a series of 126 consecutive cases


Palpable Abdominal Mass Suspected Neoplasm. Palpable Abdominal Mass-Suspected Neoplasm of fatty masses, MRI had a sensitivity of 100%, specificity of 83%, accuracy of 84%, and negative predictive value of 100% for differentiating simple lipoma from liposarcoma [40]. Although helpful in defining relationship of masses to adjacent fascia, muscles, and vessels, MRI is often not specific enough to establish a definitive diagnosis, and biopsy or excision is usually required following consultation or referral by oncologic specialists [29,38]. CT Abdomen There is little recent literature on the accuracy and diagnostic yield of CT for abdominal wall masses; however, CT is widely considered fast and accurate for excluding or confirming a mass. Because of the relative lack of soft- tissue resolution compared with MRI, it may not be a first- or second-line option for evaluation of abdominal masses. CT may be additionally helpful in the setting of suspected hernia, congenital abnormalities, hematomas, and infections [41,42]. Additionally, there may be a role in the setting of endometriosis for differentiation from other masses [43]. When malignant masses are suspected, CT may provide benefit of staging information related to metastatic disease in addition to defining the size, location, and relationship of a mass to adjacent structures. There are no recent studies that specifically address the question of whether CT should be performed with or without IV contrast for a palpable mass. Acquisition of CT both with and without contrast does not generally add diagnostic value. Although available evidence and experience generally supports the appropriateness of CT with IV contrast over that of noncontrast CT for evaluation of intra-abdominal organs and pathology [12,14,15], the use of noncontrast CT may be of value in some circumstances. CT may be of benefit in guiding biopsy and should be considered carefully and in conjunction with oncologic specialist when a sarcoma is suspected [30].


Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age.  Twins As an independent marker of fetal aneuploidy, nuchal translucency is particularly useful in twins because of the inability of maternal serum markers or age to identify the fetus at risk. Nuchal translucency measurement allows each fetus of a twin pregnancy to be assessed individually; the distribution of measurements does not differ significantly between singletons and twins so that standard thresholds can be used [9,10]. In dichorionic twins, fetus-specific risks are calculated on the assumption each twin has an independent risk reflected by its own nuchal translucency [2,11,12]. In monochorionic twins, a pregnancy-specific risk is calculated using the average nuchal translucency thickness of both fetuses [2,13]. As in singletons, increased nuchal translucency may also be a marker of fetal structural anomalies, genetic syndromes, and intrauterine demise in twins. 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 Nuchal Translucency Evaluation Special Imaging Considerations Measurement of the nuchal translucency has been standardized in order to improve its performance in screening for fetal aneuploidy. Quality assurance programs for nuchal translucency assessment have been established by the Fetal Medicine Foundation in London and the Nuchal Translucency Quality Review in the United States.


Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age. The ACR Appropriateness Criteria methodology assumes that each imaging procedures is performed and interpreted by an expert, but it should be noted that there remains considerable inter- and intra-observer variability in nuchal translucency measurements, highlighting the importance of ongoing quality assessment [14,15]. First trimester screening algorithms can be improved by assessing for the presence or absence of the nasal bone and adjusting aneuploidy risk calculations accordingly [16]. The absence of the nasal bone at 11 to 14 weeks is another powerful US marker of fetal aneuploidy; it improves the performance of early screening by decreasing the false- positive rate to 2.5% [16]. Other first trimester US markers of fetal aneuploidy such as increased frontomaxillary facial angle, an aberrant right subclavian artery, presence of tricuspid regurgitation, reversed a-wave in the ductus venosus, and increased iliac wing angle have not been incorporated into routine screening algorithms and their clinical usefulness in the general population remains uncertain [17]. The role of nuchal translucency measurement in the new era of cell-free fetal DNA screening is also uncertain. It is recommended that a first trimester US for the sole purpose of nuchal translucency screening not be performed in patients with negative cell-free fetal DNA [18]. OR Discussion of Procedures by Variant Variant 1: Routine nuchal translucency measurement at 11 to 14 weeks of gestation for single or twin gestations. Initial imaging. US Duplex Doppler Pregnant Uterus Although the utility of Doppler imaging has been investigated in research protocols, there is no literature to support a recommendation to universally incorporate Doppler studies into routine first trimester screening algorithms for fetal aneuploidy [17].


Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age. Given the theoretical risk of thermal damage to the developing fetus from the use of color and pulsed Doppler US, its use is not advised when the nuchal translucency is of normal thickness or below the threshold of 3 mm at 11 to 14 weeks of gestation [2,19]. US Echocardiography Fetal In the absence of other maternal or fetal risk factors, there is no literature to support the routine use of fetal echocardiography in patients with normal nuchal translucency measurements at 11 to 14 weeks of gestation [20]. US Pregnant Uterus Transabdominal ACOG recommends aneuploidy screening or diagnostic testing be offered to all women in early pregnancy [2]. For women who choose screening over invasive diagnostic testing, first trimester combined screening with nuchal translucency and maternal serum markers remains a reasonable option for single and twin gestations [2,18,21]. Although ACOG does not endorse a specific screening test, citing that no one screening test is superior to another in all test characteristics, there are several benefits of first trimester screening, including maternal privacy, early reassurance, and timely detection of fetal abnormalities with the option for earlier and safer pregnancy termination [2]. Using the nuchal translucency measurement and maternal serum pregnancy-associated plasma protein A and free beta subunit of human chorionic gonadotropin levels, most laboratories will report specific risk estimates for trisomy 21, 18, and 13 after adjusting for crown-rump length and maternal factors such as age, prior history of aneuploidy, weight, and race [2]. In clinical practice, first trimester combined screening for aneuploidy detects about 90% of affected pregnancies at a false positive rate of 5% for single gestations with slightly lower sensitivities reported for twins [12,17].


Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age. US Pregnant Uterus Transvaginal Transvaginal US may be utilized for first trimester aneuploidy screening if optimal views of the nuchal translucency cannot be obtained using the transabdominal approach, which occurs in about 5% of patients [5,24,28]. The higher resolution of transvaginal US can be particularly helpful when imaging women with high body mass indexes. The transvaginal approach may also be favored in patients with multiple abdominal surgeries or presenting with a transverse fetal lie in the lower aspect of the uterus. However, reduced probe mobility limits the available image planes, so using a combination of transabdominal and transvaginal US may be necessary to fully assess the first trimester fetus. Fetal nuchal translucency measurements are similar whether measured by transabdominal or transvaginal US as long as the same principles for image acquisition and nuchal translucency measurement are applied [29]. The transvaginal approach may produce better quality images to assess the nasal bone than transabdominal US [65]. However, perhaps because of the restricted range of movement, a 3-fold higher failure of nasal bone imaging has been reported with transvaginal US [30]. If there is difficulty obtaining the nuchal translucency measurement, there is likely to be difficulty in obtaining the proper image to assess for the presence or absence of nasal bone regardless of approach. The ductus venosus can be easily identified by its accelerated flow velocity on color Doppler and then interrogated with pulsed Doppler to assess its flow characteristics. The triphasic waveform of the ductus venosus, reflecting the phases of the cardiac cycle, normally has forward flow toward the heart at all times; a reversed a-wave, corresponding to retrograde flow during atrial contraction, is abnormal.


Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age. Although the cause of this abnormality in fetal aneuploidy is uncertain, a reversed a-wave is seen in 3% to 4% of euploid fetuses compared to about 70% of trisomy 21 and trisomy 18, 65% of trisomy 13, and 75% of Turner syndrome fetuses [34]. The addition of ductus venosus Doppler assessment to nuchal translucency measurement improves the detection rate of trisomy 21 to 96% with 3% false positive rate [34]. Ductus venosus a-wave abnormalities are also associated with congenital heart disease [35]. In chromosomally normal fetuses with an increased nuchal translucency, a reversed a-wave in the ductus venosus is associated with a 3-fold increase in the likelihood of a major heart anomaly; a normal ductus Nuchal Translucency Evaluation Nuchal Translucency Evaluation The risk of an adverse pregnancy outcome is proportional to the degree of nuchal translucency enlargement; there is an increased risk of intrauterine demise in fetuses with large nuchal translucencies, even in the absence of associated chromosomal or structural abnormalities [22,23]. Although there are no studies that specifically address the optimal management of these pregnancies after the initial US evaluation and diagnostic testing, serial fetal surveillance is usually added to routine prenatal care with periodic US examinations to monitor fetal growth and well-being [2,45]. US Pregnant Uterus Transvaginal A transvaginal US may be advantageous in patients with an increased nuchal translucency, particularly if planning to assess for additional first trimester markers of fetal aneuploidy or screen for major anomalies in women with increased body mass indexes, abdominal wall scarring, or fetal positioning in the lower uterus. Fetal nuchal translucency measurements are similar as long as the same principles for image acquisition are applied, so obtaining a transvaginal measurement is not required if transabdominal imaging is satisfactory [29].


Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age. However, high resolution transvaginal US may more clearly identify the amnion and nuchal translucency borders to ensure an accurate maximal measurement in patients with suboptimal transabdominal views. US Echocardiography Fetal An increased nuchal translucency in a dichorionic twin is an indication to obtain a fetal echocardiogram [20]. Performing fetal echocardiography on twins is challenging because of both maternal factors, such as increased body mass index or inability to rest comfortably during a lengthy examination, and fetal factors, such as unfavorable fetal position or limited views due to the presence of a co-twin. Although early fetal echocardiography may be attempted, a standard fetal echocardiogram at 18 to 22 weeks with an expected detection rate of over 80% for major cardiac anomalies is recommended when increased nuchal translucency is detected in dichorionic twins [26,44]. One of the advantages of nuchal translucency screening in dichorionic twins is the ability to perform individual measurements on each fetus and generate fetus-specific risks [45]. The management of a positive screen or an increased nuchal translucency is similar in twins and singletons; genetic counseling, diagnostic testing, and in continuing pregnancies with a history of increased nuchal translucency or diagnosed with fetal aneuploidy, a detailed anatomic survey, and fetal echocardiography in the second trimester are recommended. The prevalence of increased nuchal translucency in dichorionic twins with a normal karyotype is similar to that in singletons [56]. Although an individual risk can be estimated for each twin and a patient may opt for only sampling the twin suspected to be at risk, it is customary to sample both twins at the time of diagnostic testing to avoid a missed diagnosis because of averaged maternal biochemistries or incorrect assignment of chorionicity [57].


Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age. For those who decline diagnostic testing, an evaluation for additional first trimester markers of fetal aneuploidy such as the presence or absence of the nasal bone may assist in patient counseling; however, nasal bone assessment is more challenging in twin pregnancies [58]. Nuchal Translucency Evaluation After the second trimester anatomy survey and fetal echocardiogram, there are no robust evidence-based recommendations for the US follow-up of dichorionic twins with increased nuchal translucency. However, given the risk for intrauterine demise, it is reasonable that serial surveillance of fetal growth and well-being be performed in the third trimester [45,59,60]. US Pregnant Uterus Transvaginal As in singleton pregnancies, transvaginal US can be utilized at 11 to 14 weeks of gestation to assess the nuchal translucency, additional markers of aneuploidy, as well as early fetal anatomy in dichorionic twins. Fetal nuchal translucency measurements are similar as long as the same principles for image acquisition and measurement are employed [29]. Given the larger uterine dimensions from the presence of two fetuses, two sacs of amniotic fluid, and two placentas, a combination of both transabdominal and transvaginal imaging may be optimal to fully assess dichorionic twins with increased nuchal translucency. Variant 4: Increased nuchal translucency in monochorionic twins at 11 to 14 weeks of gestation. US Duplex Doppler Pregnant Uterus The detection of abnormal flow across the tricuspid valve or in the ductus venosus by color and pulsed Doppler increases the likelihood of fetal aneuploidy in monochorionic twins with increased nuchal translucency. In addition, both reversed or absent a-waves in the ductus venosus have been reported to be markers for congenital heart disease and the development of twin-twin transfusion syndrome later in gestation [61,62].


Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age. Although Doppler imaging is likely of little to no value in uncomplicated monochorionic twins, serial assessment of the ductus venosus, umbilical artery and vein, and middle cerebral artery may be useful in cases complicated by unequal placental sharing, twin- twin transfusion syndrome, or twin anemia polycythemia sequence [45]. US Echocardiography Fetal Because of the substantial risk of congenital heart disease, there is strong evidence to support the use of fetal echocardiography for all monochorionic twins, regardless of the nuchal translucency measurement [20]. The overall risk of congenital heart disease in monochorionic twins is 2%, double the background risk of a singleton, and increases to 5% in cases of twin-twin transfusion syndrome, particularly among recipient twins [63]. Recipient twins often demonstrate evidence of volume overload with increased pulmonary and aortic velocities, cardiomegaly, and atrioventricular regurgitation, which, over time, can result in biventricular hypertrophy and diastolic dysfunction [64]. Poor right ventricular systolic function can lead to functional right ventricular outflow tract obstruction in up to 10% of recipient twins, which may progress to severe pulmonic stenosis and a poor prognosis [64]. In contrast, recipient twins with normal cardiac function have improved survival [65]. Therefore, in addition to excluding structural heart defects in monochorionic twins, fetal echocardiography with a detailed functional assessment may be useful in identifying cases of twin-twin transfusion syndrome that would benefit from fetoscopic laser therapy and in evaluating the response to treatment.


Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age. Although an increased nuchal translucency may prompt early echocardiography in monochorionic twins, standard second trimester fetal echocardiography is warranted in all monochorionic twins because of the substantial risk of both structural and functional heart abnormalities regardless of the nuchal translucency measurements [59,65]. US Pregnant Uterus Transabdominal First trimester combined screening with nuchal translucency and maternal serum markers is currently a common choice for aneuploidy screening in monochorionic twins [53,54]. In monochorionic twins, each fetus is assumed to have the same risk of aneuploidy equivalent to the maternal age risk of a singleton. Therefore, aneuploidy risk estimates for trisomy 21, 18, and 13 are calculated using the mean nuchal translucency measurement of the twins, usually obtained via transabdominal US. Overall, first trimester combined screening in monochorionic twins provides detection rates of fetal aneuploidy similar to that reported in singletons but with a higher false positive rate [11,53]. A meta-analysis of first trimester combined aneuploidy screening reported a sensitivity of 87.4% for monochorionic twins compared to 86.2% for dichorionic twins [54]. Nuchal translucency measurements have been observed to be higher in monochorionic twins compared to dichorionic twins, which may explain the higher false- positive rate of aneuploidy screening in monochorionic twin pregnancies. In monochorionic twins with increased nuchal translucency thickness, an assessment for additional first trimester markers of fetal aneuploidy, such as the absence of the nasal bone, may be helpful to patients trying to decide whether to undergo invasive diagnostic testing [58]. Increased nuchal translucency thickness in a monochorionic twin may also be an early manifestation of inter- fetal transfusion and early hypervolemic congestion in a recipient twin.


Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age. Indeed, both nuchal translucency abnormalities and crown-rump length discrepancies have been associated with an increased risk of twin-twin Nuchal Translucency Evaluation transfusion syndrome [66-68]. A crown-rump discrepancy of >10% is associated with almost a doubling the risk of developing twin-twin transfusion syndrome [67,68]. Nuchal translucency discordance >20% has been associated with a >30% risk of severe twin-twin transfusion syndrome and early fetal death compared with a <10% risk when the discordance is <20% [69]. As in singletons and dichorionic twins, an increased nuchal translucency in monochorionic twins is associated with fetal aneuploidy, genetic syndromes, structural anomalies, and intrauterine demise. Genetic counseling, invasive diagnostic testing, fetal anatomic surveys, and fetal echocardiography are recommended in monochorionic twin pregnancies complicated by increased nuchal translucency thickness affecting one or both twins. Serial US surveillance of monochorionic twins is advised because of complications associated with sharing a single placenta such as twin-twin transfusion syndrome, unequal placental sharing with discordant twin growth and selective intrauterine growth restriction, and twin anemia polycythemia sequence [64,70]. Because of these unique complications, women with monochorionic pregnancies are followed more closely than dichorionic pregnancies; serial US evaluations every 2 weeks starting at 16 weeks until delivery should be considered [45]. Despite its potential value, a recent review concluded that it is not currently possible to predict adverse outcomes in monochorionic twin pregnancies based on nuchal translucency assessment alone [71].


Preprocedural Planning for Transcatheter Aortic Valve Replacement.  Introduction/Background Transcatheter aortic valve replacement (TAVR) has dramatically impacted the management of high-risk surgical patients [1-10], as well as medium- and low-risk patients [11], for the treatment of aortic valve disease. TAVR is a less invasive route (percutaneous endovascular) to position a prosthesis at the aortic annulus that displaces the native aortic valve leaflets toward the aortic wall. Procedure-related complications [3,5,7,8] are linked to inaccurate estimates of annular geometry; unlike surgical aortic valve replacement, the aortic annulus is not directly inspected by the proceduralist at the time of the procedure, and multiple parameters related to the annulus should be measured. Because the annulus has a complex geometry, volumetric data have emerged with standardized reformatting along patient-specific anatomic planes for annular assessment and device sizing [1,2,4,9,10,12-26]. Accurate measurements guide optimal choices for device sizing and deployment, with a secondary reduction in TAVR-related complications. The catheter-based system ranges in size between 14 and 24 Fr with transfemoral, transaxillary, and transaortic as well as direct aortic and left ventricular approaches reported; the entire aorta and branches to potential access points are evaluated for the presence, burden, and distribution of peripheral vascular atherosclerosis. This document does not elucidate the diagnosis of aortic valve disease, surgical risk stratification, [27-32] or the assessment of coronary artery disease. It is presumed that patients considered in this document are candidates for TAVR. Also, the panel did not consider planning done at the time of intervention with either catheter angiography, echocardiography, or a combination of both.