Staging and Follow up of Esophageal Cancer.  Introduction/Background Esophageal cancer is the eighth most common cancer and the sixth most common cause of cancer death worldwide. The American Cancer Society estimates there will be 19,260 new cases of and 15,530 deaths from esophageal cancer in the United States in 2021 [1]. Squamous cell carcinoma and adenocarcinoma comprise 98% of malignant tumors of the esophagus. Worldwide, squamous cell carcinoma is still more common, but in Western countries, adenocarcinoma now predominates and accounts for more than 60% of cases. In general, squamous cell carcinoma usually occurs in the upper and middle esophagus, whereas adenocarcinoma predominates in the lower esophagus [2]. For esophageal cancers, initial clinical staging uses a combination of imaging modalities with biopsies used to confirm suspected sites of disease. Specific strategies for the evaluation of the patient with esophageal cancer vary by institution not only in terms of the modalities used but in the order in which they are used. One common strategy is initial esophagogastroduodenoscopy and esophageal ultrasound (US) to determine cell type, grade, local extent, and locoregional nodal involvement followed by fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT to provide additional information on nodal disease and to evaluate for distant metastases. Another common strategy involves using CT or FDG-PET/CT first to evaluate for findings of metastatic disease. If metastatic disease is found, further evaluation with esophagogastroduodenoscopy and esophageal US may not be warranted [3]. The identification of distant metastatic disease is critical in the evaluation of the patient with newly diagnosed esophageal cancer because it will direct them to a treatment pathway centered on palliative chemoradiation rather than surgery. A secondary concern is the confirmation of locoregional spread because this is often an important determinant in whether neoadjuvant chemoradiation is used.


Staging and Follow up of Esophageal Cancer. If neoadjuvant chemoradiation is employed, follow- up imaging before definitive surgical treatment is necessary. Although the utility of follow-up imaging, particularly FDG-PET/CT, is of debate during and after neoadjuvant therapy to predict response, it does have a critical role in evaluating for the interval development of distant metastases and is commonly used for this purpose. OR aMallinckrodt Institute of Radiology, Saint Louis, Missouri. bUMass Medical School, Worcester, Massachusetts. cPanel Chair, Duke University, Durham, North Carolina. dPanel Chair, University of Alabama Medical Center, Birmingham, Alabama. eThe University of Chicago, Chicago, Illinois; American Society of Clinical Oncology. fEmory University Hospital, Atlanta, Georgia. gHampton VA Medical Center, Hampton, Virginia. hUniversity of California San Francisco, San Francisco, California, Hospitalist. iUniversity of Michigan Health System, Ann Arbor, Michigan. jUniversity of North Carolina Hospital, Chapel Hill, North Carolina; The Society of Thoracic Surgeons. kUniversity of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. lUniversity of Arizona College of Medicine, Phoenix, Arizona. mVanderbilt University Medical Center, Nashville, Tennessee. nNational Institutes of Health, Bethesda, Maryland. oThe University of Texas MD Anderson Cancer Center, Houston, Texas; Commission on Nuclear Medicine and Molecular Imaging. pDavid Grant Medical Center, Travis AFB, California. qSpecialty Chair, Johns Hopkins University School of Medicine, Baltimore, Maryland. rSpecialty Chair, Ohio State University Wexner Medical Center, Columbus, Ohio. 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.


Staging and Follow up of Esophageal Cancer. 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 Staging and Follow-up of Esophageal Cancer Discussion of Procedures by Variant Variant 1: Newly diagnosed esophageal cancer. Pretreatment clinical staging. Initial imaging. CT Chest and Abdomen For the purposes of this document, CT examinations are considered as being performed with intravenous (IV) contrast. There is no relevant literature supporting the use of CT for evaluation of the extent of tumor extension into the esophageal wall in T1 to T3 tumors. There are, however, older studies that investigated the use of CT for the evaluation of extension into adjacent structures. Picus et al [4] reviewed CT examinations in 52 patients with esophageal carcinoma, 30 of whom had surgery or autopsy, and found that CT appearance correctly determined aortic involvement in 24 of 25 cases, with 5 indeterminate. Takashima et al [5] prospectively reviewed CT examinations on 35 patients and the reported sensitivity, specificity, and accuracy for resectability (defined as absence of evidence of invasion of adjacent structures) to be 100%, 80%, and 84%, respectively. A meta-analysis by Puli et al [6] reviewed data from 49 studies and 2,558 patients and reported pooled sensitivity and specificity of 92.4% and 97.4%, respectively, in the diagnosis of T4 disease. Unlike CT, esophageal US can also evaluate wall involvement of lower T stage tumors, with the meta-analysis by Puli et al [6] reporting sensitivity and specificity for T1 tumors of 81.6% and 99.4%, T2 tumors of 81% and 96%, and T3 tumors of 91.4% and 94.4%, respectively. There is no relevant literature supporting the use of CT for nodal staging.


Staging and Follow up of Esophageal Cancer. A study by Choi et al [7], which prospectively evaluated 109 patients with esophageal cancer, used a short-axis diameter of 8 mm for the determination of positive nodes and reported a sensitivity of 35% and specificity of 93% for CT. CT is limited in the evaluation of nodal metastatic disease because multiple studies have shown that nodal metastases often occur in small lymph nodes in patients with esophageal cancer. Foley et al [8] evaluated 112 patients with multiple modalities and reported an accuracy of 54.5%, a sensitivity of 55.4%, a sensitivity of 39.7%, and a specificity of 77.4% for CT. Foley et al [8] also reported that 82% of positive lymph nodes measured <6 mm. Similarly, Kajiyama et al [9] reported that two-thirds of 320 metastatic lymph nodes assessed by surgery were <5 mm, further reinforcing that preoperative anatomic imaging evaluation will have a limited role in the detection of nodal metastatic disease. In terms of clinical relevance, Bunting et al [10] prospectively studied 133 patients undergoing surgery and reported an N stage accuracy of 75.6%. Their conclusion was that staging accuracy of locoregional disease with respect to the neoadjuvant threshold was poor with all modalities, including CT, and could potentially lead to over- and undertreatment. The principle use of CT in the initial evaluation of patients with esophageal cancer is in detecting metastatic disease. CT has been compared with PET and FDG-PET/CT by several authors. Heeren et al [11] compared combined CT/esophageal US with PET and reported that sensitivity for distant nodal and systemic metastatic disease increased from 37% with CT/esophageal US to 78% with PET. Similarly, Hocazade et al [12] prospectively evaluated 91 patients with PET/CT and CT and reported that 47.3% of patients had metastases detected on PET/CT that were not detected by CT.


Staging and Follow up of Esophageal Cancer. Thus, although CT can detect metastases in the setting of esophageal cancer, it has been found to be less sensitive than PET and FDG-PET/CT even when combined with esophageal US. The described literature presented here is based on contrast-enhanced CT. There are no reliable studies reporting the use of CT without IV contrast. When CT is used in the initial staging of esophageal cancer, contrast is recommended for optimal performance. CT Chest, Abdomen, and Pelvis For the purposes of this document, CT examinations are considered as being performed with IV contrast. Including the pelvis in CT for esophageal cancer would not affect the performance of CT for locoregional staging. The studies presented above by Heeren et al [11] and Hocazade et al [12] for the evaluation of systemic metastatic disease used CT of the chest and abdomen only. There are no studies that directly compare CT of the chest and abdomen with CT of the chest, abdomen, and pelvis; thus, the utility or added value of including the pelvis for the initial staging of esophageal cancer is not known. FDG-PET/CT Skull Base to Mid-Thigh Although there have been many studies evaluating the use of FDG-PET/CT in the evaluation of the primary tumor for prognosis, data supporting its use for T and N staging are limited. Walker et al [13] prospectively evaluated 81 patients with esophageal cancer with FDG-PET/CT and esophageal US and determined that esophageal US was superior to FDG-PET/CT for T staging and identifying locoregional lymph nodes. Hsu et al [14] investigated the use of PET/CT in 45 patients undergoing surgical resection for esophageal cancer and found that the maximum standardized uptake value (SUV)max showed potential in differentiating T1 from higher T stage tumors. In the same Staging and Follow-up of Esophageal Cancer study, however, the sensitivity, specificity, and accuracy of PET/CT for nodal involvement were 57.1%, 83.3%, and 71.1%, respectively.


Staging and Follow up of Esophageal Cancer. Foley et al [8] also reported sensitivity, specificity, and accuracy of FDG-PET/CT of 77.3%, 75%, and 90.9%, respectively, for nodal involvement in a prospective study of 112 patients with esophageal cancer. Given that 82% of lymph node metastases were <6 mm in this study, the authors concluded that imaging staging for N disease was poor. Bunting et al [10] prospectively evaluated 133 patients with esophageal cancer undergoing surgery and reported an N stage accuracy of 78.6% for FDG-PET/CT. Bunting et al [10] also concluded that staging accuracy with respect to the threshold for treatment for neoadjuvant chemoradiation was poor and could lead to over- and undertreatment. A meta-analysis by van Westreenen et al [15] reported pooled sensitivity of 51% and specificity of 84% for FDG-PET/CT for locoregional metastases. Limited performance of FDG-PET/CT in locoregional staging is likely due to poor spatial resolution of PET and the reality that metastatic lymph nodes in esophageal cancer are often small. Even some primary tumors may not be detected with FDG-PET/CT either because of small size or in histologic subtypes with low FDG uptake [2]. There are many studies that have evaluated the use of FDG-PET/CT in detecting M disease in initial staging. Heeren et al [11] investigated 74 patients with FDG-PET/CT and found that FDG-PET/CT increased detection of M1 disease from 37% to 78% in comparison with CT/esophageal US. Vyas et al [16] prospectively investigated 114 patients with biopsy-proven esophageal adenocarcinoma and reported a sensitivity of 57.14% and specificity of 84.53% in detecting metastatic disease. A larger meta-analysis by van Westreenen et al [15] reported a pooled sensitivity and specificity for FDG-PET/CT of 67% and 97%, respectively, in the detection of M1 disease in esophageal cancer.


Staging and Follow up of Esophageal Cancer. In terms of effects on clinical staging, You et al [17] prospectively evaluated 491 patients with esophageal cancer with FDG-PET/CT and reported clinically important stage changes in 188 (24%) patients. In a smaller cohort, Williams et al [18] reported the use of FDG-PET/CT changing initial staging in 10 of 38 (26%) patients with esophageal cancer, with 7 of 38 (18%) patients having a concomitant management change. FDG-PET/MRI Skull Base to Mid-Thigh There are no substantial data supporting the use of FDG-PET/MRI in the staging of esophageal cancer. In a small study evaluating 19 patients with esophageal cancer who underwent esophageal US, CT, FDG-PET/CT, and FDG- PET/MRI, Lee et al [19] reported acceptable T staging compared with esophageal US and statistically nonsignificant but higher accuracy than esophageal US and FDG-PET/CT for N staging. Impact on M staging was not reported. Given available data on the performance of FDG-PET/CT in the evaluation of M disease, it would be expected that FDG-PET/MRI may have similar potential, but data supporting its use are not yet available. Fluoroscopy Upper GI Series There is no relevant literature to support the use of fluoroscopy upper gastrointestinal (GI) series in the staging of esophageal cancer. MRI Chest and Abdomen There is only limited evidence supporting the use of MRI chest and abdomen in the evaluation of patients with esophageal cancer. Giganti et al [20] compared MRI, CT, esophageal US, and FDG-PET/CT in 27 patients with esophageal cancer. In this small study, contrast-enhanced MRI with diffusion-weighted imaging showed higher specificity (92%) and accuracy (82%) for T staging, but esophageal US was the most sensitive modality. MRI showed the highest reported accuracy for N stage (66%) in this study, although this would be in line with values previously determined for other imaging modalities.


Staging and Follow up of Esophageal Cancer. Qu et al [21] prospectively evaluated the use of contrast- enhanced radial VIBE sequences in the T staging of 43 patients with esophageal cancer and determined higher accuracy with MRI for T3 and T4 tumors. Malik et al [22] compared FDG-PET/CT and whole-body MRI in 49 patients, reporting similar performance for locoregional staging. Both modalities identified distant metastases that were present in 2 of the patients. Radiography Chest There is no relevant literature to support the use of chest radiography in the initial staging of patients with esophageal cancer. Variant 2: Esophageal cancer. Imaging during treatment. CT Chest and Abdomen For the purposes of this document, CT examinations are considered as being performed with IV contrast. There is no relevant literature supporting the use of CT in patients who have undergone neoadjuvant chemoradiation. There Staging and Follow-up of Esophageal Cancer are 2 studies that discourage its use for the evaluation of tumor response. In a study investigating 39 patients, van Heijl et al [23] reported that tumor volume changes identified on CT at 14 days were not associated with histopathologic tumor response. In a study evaluating the use of CT before and after neoadjuvant therapy in 35 patients with esophageal cancer, Konieczny et al [24] determined that CT accurately predicted complete histopathologic response in 20% and overstaged in 80%. An older systematic review by Westerterp et al [25] that reviewed 4 studies with CT showed the maximum joint value for sensitivity and specificity for CT in predicting response to neoadjuvant therapy was 54%. It should be noted that another important purpose of imaging patients after neoadjuvant therapy is to evaluate for the interval development of metastases. Although there are no studies evaluating CT specifically for this purpose, it would be expected to perform similarly to initial staging.


Staging and Follow up of Esophageal Cancer. CT Chest, Abdomen, and Pelvis There is no relevant literature to support the inclusion of the pelvis in CT examinations during treatment. FDG-PET/CT Skull Base to Mid-Thigh There are conflicting data on the use of FDG-PET/CT for the evaluation of patients undergoing neoadjuvant chemotherapy. A systematic review of the literature in 2004 by Westerterp et al [25] assessed 7 studies using FDG- PET for the assessment of response to neoadjuvant chemotherapy in esophageal cancer. The maximum joint sensitivity and specificity for FDG-PET for in detecting response was 85%, with an accuracy similar to esophageal US and superior to CT. Subsequent studies showed promising results for FDG-PET/CT. Gabrielson et al [26] prospectively evaluated 51 patients undergoing neoadjuvant chemotherapy for esophageal cancer and found that SUVs could be used to differentiate responders from nonresponders but were not found to demonstrate statistical significance in patients with complete versus subtotal response. Beukinga et al [27] prospectively evaluated 74 patients using a radiomics-based quantitative assessment of postneoadjuvant chemoradiation FDG-PET/CT examinations and concluded that posttreatment FDG-PET/CT orderliness combined with clinical T staging resulted in high discriminatory accuracy in predicting complete histopathologic response. Thurau et al [28] conducted a retrospective review of 83 patients with esophageal cancer who had FDG-PET/CT performed at 6 weeks after induction of neoadjuvant therapy. The authors reported that an SUV reduction of >50% correlated with major histomorphologic response and that patients with this reduction also showed significantly increased survival. Other authors, however, found fewer promising results when evaluating FDG-PET/CT for the assessment of response to neoadjuvant therapy.


Staging and Follow up of Esophageal Cancer. Vallbohmer et al [29] prospectively evaluated 119 patients with FDG-PET/CT 2 to 3 weeks after induction of neoadjuvant chemotherapy and found no significant association between major responders and FDG-PET/CT results; receiver operating characteristic analysis could not identify an SUV threshold to predict histomorphologic response, and there was no association between metabolic imaging and prognosis. Elliot et al [30] prospectively evaluated 100 patients with esophageal cancer who underwent FDG-PET/CT at 2 to 4 weeks after completion of neoadjuvant therapy and concluded FDG-PET/CT had poor prognostic value and clinical application for determining responders. Piessen et al [31] prospectively evaluated 46 patients with esophageal cancer who had FDG-PET/CT performed 4 to 6 weeks after completion of neoadjuvant therapy and concluded that FDG-PET/CT did not correlate with pathological response and long-term survival in patients with locally advanced esophageal cancer. Van Heijl et al [32] prospectively studied patients with esophageal cancer who had FDG- PET/CT at 2 weeks after the induction of chemotherapy and found FDG-PET/CT showed a statistically significant decrease in SUV in responders and correctly identified 58 of 64 responders and 18 of 36 nonresponders. The authors concluded that the low accuracy in detecting nonresponders did not justify using FDG-PET/CT for early discontinuation of neoadjuvant chemotherapy. FDG-PET/CT also has the potential to detect metastases that have developed in the interval after the induction of neoadjuvant therapy. A systematic review and meta-analysis performed by Kroese et al [33] evaluated 14 studies (1,110 patients) and found a pooled proportion of 8% of patients having interval metastases detected by FDG- PET/CT. The authors also reported an additional pooled proportion of 5% of patients who had false-positive concerning distant findings.


Staging and Follow up of Esophageal Cancer. Kroese et al [33] concluded that the detection of distant metastases on restaging FDG- PET/CT after induction of neoadjuvant therapy can considerably impact decision making but that suspicious imaging findings required pathologic confirmation. FDG-PET/MRI Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/MRI during treatment. Fluoroscopy Upper GI Series There is no relevant literature to support the use of fluoroscopy upper GI series during treatment. Staging and Follow-up of Esophageal Cancer MRI Chest and Abdomen There are limited data from small series investigating the use of MRI for the evaluation of patients undergoing treatment. A prospective study of 26 patients undergoing neoadjuvant therapy for esophageal cancer who underwent dynamic contrast-enhanced MRI by Heethuis et al [34] demonstrated that the area under the curve could predict good responders and poor responders with a sensitivity of 92% and a specificity of 77%. Sun et al [35] used dynamic contrast-enhanced MRI to evaluate patients with advanced squamous cell cancer of the esophagus and reported that the change in Ktrans was a parameter that could be potentially used to assess treatment response. Wang et al [36] studied 38 patients with squamous cell cancer of the esophagus undergoing chemoradiotherapy with weekly MRI including diffusion-weighted imaging. The authors reported that treatment-induced change in apparent diffusion coefficient during the first 2 to 3 weeks could be used to assess response to therapy. Wang et al [37] prospectively studied 79 patients with esophageal cancer who had 3T MRI before and after neoadjuvant therapy and reported a sensitivity, specificity, and accuracy of more than 90% for several sequences in T staging after neoadjuvant therapy. No studies are available that investigate the performance of MRI for detecting interval metastases in patients undergoing neoadjuvant therapy.


Staging and Follow up of Esophageal Cancer. Radiography Chest There is no relevant literature to support the use of chest radiography during treatment. Variant 3: Esophageal cancer. Posttreatment imaging. No suspected or known recurrence. CT Chest and Abdomen For the purposes of this document, CT examinations are considered as being performed with IV contrast. CT has been studied in the evaluation of patients who have completed treatment. Recent data exist from studies comparing FDG-PET and FDG-PET/CT with contrast-enhanced CT in the detection of recurrence. Kato et al [38] studied 55 patients and reported 89% sensitivity, 79% specificity, and 84% accuracy for CT in detecting recurrent disease in comparison with 96% sensitivity, 68% specificity, and 82% accuracy for FDG-PET. The authors did note that CT was more sensitive than FDG-PET for the detection of lung metastases. Teyton et al [39] prospectively studied 41 patients postsurgery for esophageal cancer and reported 65% sensitivity and 91% specificity for chest and abdomen CT versus 100% sensitivity and 85% specificity for FDG-PET. Of note, in a retrospective review by Antonowicz et al [40], 169 patients who underwent esophagectomy and were followed with annual CT had no change in management or survival. CT Chest, Abdomen, and Pelvis There are no specific studies comparing body CT scans that include the pelvis with those that do not in asymptomatic patients undergoing CT to evaluate for recurrent disease. FDG-PET/CT Skull Base to Mid-Thigh Several studies have evaluated FDG-PET/CT in the evaluation of asymptomatic patients who have had definitive treatment for esophageal cancer. Betancourt et al [41] studied 162 asymptomatic patients who underwent surgery for esophageal cancer and were followed with FDG-PET/CT. They reported a sensitivity of 77% and specificity of 76% for recurrence at the anastomosis, sensitivity of 88% and specificity of 85% for regional node recurrence, and sensitivity of 97% and specificity of 96% for distant metastases.


Staging and Follow up of Esophageal Cancer. A systematic review of the literature by Goense et al [42] evaluating 486 patients across 8 studies reported a pooled sensitivity of 96% and a specificity of 78% in detecting recurrent disease. There was no statistically significant difference in the performance of FDG-PET/CT in patients who were asymptomatic or had a clinical indication for the examination. FDG-PET/MRI Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/MRI to follow asymptomatic patients after treatment. Fluoroscopy Upper GI Series There is no relevant literature to support the use of fluoroscopy upper GI series to follow asymptomatic patients after treatment. MRI Chest and Abdomen There is no relevant literature to support the use of MRI chest and abdomen to follow asymptomatic patients after treatment. Staging and Follow-up of Esophageal Cancer Radiography Chest There is no relevant literature to support the use of chest radiography to follow asymptomatic patients after treatment. Variant 4: Esophageal cancer. Posttreatment imaging. Suspected or known recurrence. CT Chest and Abdomen For the purposes of this document, CT examinations are considered as being performed with IV contrast. Sharma et al [43] studied 227 patients with suspected esophageal cancer who had suspected metastasis. All patients underwent FDG-PET/CT, whereas 109 patients also underwent contrast-enhanced CT. The authors reported a sensitivity of 96% and a specificity of 81% for FDG-PET/CT compared with a 97% sensitivity and a 21% specificity for contrast-enhanced CT. CT Chest, Abdomen, and Pelvis There are no specific studies comparing body CT scans that include the pelvis with those that do not in patients undergoing CT to evaluate for clinically suspected recurrent disease. FDG-PET/CT Skull Base to Mid-Thigh As above, Sharma et a [43] studied 227 patients with suspected esophageal cancer who had suspected metastasis.


Pulmonary Arteriovenous Malformation PAVM .  About 70% to 90% of the patients with PAVMs have hereditary hemorrhagic telangiectasia (HHT) [2]. HHT is an autosomal dominant disorder associated with mutations in genes coding for endoglin and activin receptor-like kinase 1ALK1. The former leads to a phenotypical presentation with cerebral and PAVMs described as HHT type 1 [3]. The later presents with pulmonary hypertension and hepatic AVMs and is described as HHT type 2 [4]. Of patients with HHT, 1% to 2% have a SMAD4 mutation and a clinical phenotype associated with juvenile polyposis syndrome [5]. The clinical diagnosis of HHT is based on the Curacao criteria [6]. The prevalence of PAVM occurs in 1 in 5,000 individuals in the general population but can vary depending on the geographical distribution of HHT. In areas where HHT is more prevalent, PAVM prevalence can reach between 26 and 56 per 100,000 individuals. In general, there is a 1.5 to 2 times higher incidence of PAVMs in women compared to men but a male-predominance is noted in newborns [7]. Other causes of PAVMs are rare and include trauma, chest surgery, schistosomiasis, actinomycosis, mitral valve stenosis, Fanconi syndrome, cirrhosis with hepatopulmonary syndrome, and metastatic cancer [7]. Clinical manifestations of PAVMs depend on the size, number, type (complex versus simple), and flow through the malformations. Most patients are asymptomatic (25%-58%). Hypoxemia (27%-71%) at rest or exercise, especially orthodeoxia (worsening hypoxemia when upright) and platypnea (worsening dyspnea when upright), are classical presentations as 65% to 83% of PAVMs are in the lower lobes of the lungs [8]. Transient ischemic attacks and cerebral strokes (3.2%-55%), systemic infections, and abscesses including cerebral abscesses (0%-25%) and rarely massive hemoptysis and hemothorax (0%-2%) are other manifestations [1].


Pulmonary Arteriovenous Malformation PAVM . Pregnancy is associated with the rapid growth of PAVMs due to hormonal and hemodynamic consequences with a higher risk of complications from lack of filtration and rupture [9]. Treatment of PAVMs involves endovascular occlusion of the feeding artery and in rare instances surgical resection. Percutaneous transcatheter embolization is typically performed for the treatment of PAVMs. The feeding artery is occluded by an embolic device obliterating the arteriovenous shunt. Regardless of the size of the feeding artery, any PAVM detected by CT or catheter angiography should be considered for treatment due to the risk of paradoxical embolism [10,11]. Embolization is performed by deploying coils or plugs in the feeding artery as close to the aUT Southwestern Medical Center, Dallas, Texas. bPanel Chair, Brigham & Women's Hospital, Boston, Massachusetts. cPanel Vice-Chair, Brigham & Women's Hospital, Boston, Massachusetts. dUniversity of Toronto, Toronto, Ontario, Canada; American College of Physicians. eKnight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon; Society of Cardiovascular Computed Tomography. fUT Southwestern Medical Center, Dallas, Texas; Commission on Nuclear Medicine and Molecular Imaging. gOchsner Hospital, Baton Rouge, Louisiana. hUniversity of California San Francisco, San Francisco, California. iUniversity of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. jWilmington Health, Wilmington, North Carolina; American College of Chest Physicians. kCleveland Clinic, Cleveland, Ohio. lUCLA Medical Center, Los Angeles, California; The Society of Thoracic Surgeons. mVA Puget Sound Health Care System and University of Washington, Seattle, Washington. nThe Warren Alpert School of Medicine at Brown University, Providence, Rhode Island; Nuclear cardiology expert. oSouth Texas Radiology Group, P.A., San Antonio, Texas. pMercyhealth, Rockford, Illinois. qLahey Hospital and Medical Center, Burlington, Massachusetts.


Pulmonary Arteriovenous Malformation PAVM . rEmory University, Atlanta, Georgia; American Society of Echocardiography. sBrigham & Women's Hospital, Boston, Massachusetts; Committee on Emergency Radiology-GSER. tSpecialty Chair, Massachusetts General Hospital, Boston, Massachusetts. 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 Pulmonary Arteriovenous Malformation (PAVM) arteriovenous communication as possible. Follow-up CT angiography (CTA) to detect persistence/new lesions within 6 to 12 months followed by every 3 to 5 years is recommended by the international guidelines for the diagnosis and management of HHT [10]. Persistent perfusion of PAVMs following embolization carries the continued risk of paradoxical embolism and is a vexing problem to re-treat with success rates up to 44% to 85% [12]. The persistence rates vary with the embolic material and are primarily due to arterial recanalization. Other causes include pulmonary to pulmonary and systemic to pulmonary perfusion of the venous sac. Persistent sac perfusion following embolization with different embolic materials vary from 5% to 21% for coils alone, 4% to 6% for nitinol vascular plugs, and 0% to 2% for microvascular plugs [13,14]. Use of maximum intensity projection postprocessing has shown to increase the detection rates and reduce reporting times for small PAVMs both in children and adults. Maximum intensity projection also detects the anatomy and size of the feeding artery with higher accuracy compared to thin-section conventional CT images [18-20]. Postembolization scans for PAVMs are prone to artifacts that interfere with the evaluation of persistent flow.


Pulmonary Arteriovenous Malformation PAVM . Spectral and dual-energy CT have been studied in other anatomical locations in reducing the coil and other metallic artifacts [21,22]. There are no studies evaluating their role in PAVM, but these techniques may improve posttreatment image interpretation by reducing artifacts. For the purposes of distinguishing between CT and CT angiography (CTA), ACR Appropriateness Criteria topics use the definition in the ACR-NASCI-SIR-SPR Practice Parameter for the Performance and Interpretation of Body Computed Tomography Angiography (CTA) [23]: All elements are essential: 1) timing, 2) reconstructions/reformats, and 3) 3-D renderings. Standard CTs with contrast also include timing issues and reconstructions/reformats. Only in CTA, however, is 3-D rendering a required element. This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes. OR Discussion of Procedures by Variant Variant 1: Presenting with a transient ischemic attack, or seizures, or brain abscess, or altered sensorium. Chest radiography reveals a lung nodule. Suspected pulmonary arteriovenous malformation (PAVM). Next imaging study. Arteriography Pulmonary The real-time nature of pulmonary arteriography allows for high accuracy in delineating the angioarchitecture and detection of flow characteristics such as the early draining vein. In a study comparing the specificity of pulmonary arteriography and CTA, pulmonary arteriography was noted to have a higher specificity for detecting the angioarchitecture compared to CTA (100% versus 78%) [24]. Pulmonary angiography is performed as a part of the Pulmonary Arteriovenous Malformation (PAVM) treatment procedure and does not have a standalone diagnostic role in detecting PAVM. An exception where pulmonary angiogram would be helpful as an initial diagnostic imaging tool is in a patient who is hemodynamically unstable with clinical suspicion of pulmonary hemorrhage from a PAVM [25].


Pulmonary Arteriovenous Malformation PAVM . CT Chest With IV Contrast Chest CT with IV contrast offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Contrast-enhanced CT provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism [10,26]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. CT Chest Without and With IV Contrast There is limited data to support obtaining a CT chest with and without IV contrast in the setting of suspected PAVM. A study by Nawaz et al [24] compared CT with and without IV contrast to digital subtraction angiography (DSA) for assessment of PAVMs. Their study showed superior sensitivity of CT compared to DSA for detection of PAVM; however, the specificity for CT was inferior to that of DSA. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. The benefit of using CT chest without and with IV contrast for assessing PAVM compared to stand-alone CT without IV contrast or CT with IV contrast is unclear [24]. CT Chest Without IV Contrast Noncontrast chest CT scan is helpful in confirming the diagnosis of PAVM. Like CT chest with IV contrast, Noncontrast CT offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Remy et al [28] were able to predict angioarchitecture of the PAVMs in 95% of cases using noncontrast CT and 3-D reconstruction. Cross-sectional anatomy displayed on CT chest without IV contrast is useful in treatment planning [10,27]. CTA Chest With IV Contrast CTA chest provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM.


Pulmonary Arteriovenous Malformation PAVM . Adequate precaution should be taken to prevent air embolism. Unlike CTA pulmonary arteries (CTPA), the vascular enhancement during CTA is timed for the aorta and its branches and, thus, it may help identify systemic supply to PAVMs via the systemic arteries [10,29,30]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. CTA Pulmonary Arteries With IV Contrast CTPA specifically assesses the pulmonary vasculature. IV contrast material is timed for optimum evaluation of the pulmonary arteries. Use of CTPA for evaluation of PAVM is used in clinical practice when considering a contrast- enhanced CT scan for evaluating PAVM. Like other CT techniques, CTPA offers high special resolution and can detect the number, size, and distribution of PAVMs accurately. CTPA provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air [27]. Correlating the PAVM grade with contrast-enhanced echo has been shown to be more sensitive with CTPA compared to noncontrast CT [31]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. MRA Chest Without and With IV Contrast There is no role for the routine use of MR angiography (MRA) chest without and with IV contrast in the workup of a patient suspected of a PAVM. Similar to chest CTA, MRA chest may identify systemic arterial supply to PAVM. MRA Chest Without IV Contrast There is no role for the routine use of MRA chest without IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without and With IV Contrast Contrast-enhanced MRA pulmonary arteries provides anatomical information about the presence, number, size, and location of PAVMs. Schneider et al [32] evaluated 203 patients with HHT or first-degree relatives with HHT using contrast-enhanced MRA. Patients with definite and uncertain diagnosis of PAVM on MRA underwent pulmonary angiogram. Pulmonary angiogram detected only 77% to 80% of the PAVMs that were seen on MRA. In their study, the majority of the PAVMs not detected by pulmonary angiogram were <5 mm in size. The size criterion was Pulmonary Arteriovenous Malformation (PAVM) defined as the size of the PAVM itself and not of the feeding artery. A more recent study by Van den Heuvel et al [33] investigated the sensitivity of contrast-enhanced MRA for detection of PAVMs with a feeding artery >2 cm in children and young adults. They enrolled 53 patients who had a TTCE grade 2 or 3 who underwent chest CT and were found to have the PAVM with a feeding artery >2 cm to receive a contrast-enhanced MRA. The sensitivity of contrast-enhanced MRA to detect PAVMs with a feeding artery size of >2cm was 92%, and the specificity ranged from 67% to 96%. MRA Pulmonary Arteries Without IV Contrast There is no role for the routine use of MRA pulmonary angiography without IV contrast in the workup of a patient suspected of a PAVM. Pertechnetate Albumin Pulmonary Scan There is no role for pertechnetate albumin pulmonary scan in a modern day practice. Historically, this technique was used to detect and quantify right to left shunting before and after treatment of a PAVM [34,35]. Radiography Chest The radiographic appearance of a lower lobe pulmonary nodule with a branching afferent artery and dilated efferent vein defines the classical appearance of PAVM on chest radiography. The sensitivity of chest radiography is 60% to 70% with a 98% specificity when the classical findings are present [36].


Pulmonary Arteriovenous Malformation PAVM . The afferent and efferent vasculature and smaller PAVMs may be difficult to see on a single-view chest radiograph. Best diagnostic results are obtained when a 2-view chest radiograph, posteroanterior view, and lateral view, is performed [37]. The role of chest radiography in the diagnosis of a suspected PAVM is limited due to its poor sensitivity. US Echocardiography Transesophageal There is no role for ultrasound (US) transesophageal echocardiography (TEE) as a standalone diagnostic tool in the evaluation of PAVMs. The usefulness of TEE in the context of PAVM is to rule out intracardiac shunts [38]. Its ability to demonstrate the interatrial septum and the insertion of the pulmonary veins into the left atrium is useful to evaluate the anatomical variations [39]. US Echocardiography Transesophageal With IV Contrast TEE with IV agitated saline contrast material is not routinely used to diagnose PAVM. Contrast-enhanced TEE may be helpful to locate a PAVM based on the excellent visualization of the 4 pulmonary venous ostia as veins drain into the left atrium. Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs is limited. US Echocardiography Transthoracic Resting There is no role for transthoracic echocardiography (TTE) in the resting phase for the evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38]. US Echocardiography Transthoracic With IV Contrast TTCE is an essential diagnostic test for patients suspected of having a PAVM. TTCE with agitated saline has a 98% to 99% sensitivity and a 67% to 91% specificity for detecting PAVMs [41].


Pulmonary Arteriovenous Malformation PAVM . The microbubbles are visualized after 3 to 8 cardiac cycles in the left atrium after initial opacification of the right chambers in patients with an intrapulmonary shunt [1]. TTCE does not provide any information regarding the size and location of the PAVM. Based on the appearance of the bubbles in the left atrium a semiquantitative grading system has been developed [42,43]. The grades are defined as 0 with no opacification, grade 1 with <30 bubbles, grade 2 with moderate filling, and grade 3 with complete opacification of the left atrium. The grading system correlates well with the diagnosis of PAVM, with higher grades associated with larger shunts and cerebral complications [41,44,45]. Usefulness of the grading system to predict treatment of PAVM demonstrates that grades 2 and 3 have a positive predictive value of 0.21 (95% confidence interval [CI], 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively [44]. Adverse events including air embolism are rare with TTCE occurring in <1% [46]. Variant 2: Presenting with shortness of breath, or hemothorax, or hemoptysis. Patient has history of epistaxis and family history of hereditary hemorrhagic telangiectasia (HHT). Suspected PAVM. Initial imaging. Arteriography Pulmonary The real-time nature of pulmonary arteriography allows for high accuracy in delineating the angioarchitecture and detection of flow characteristics such as the early draining vein. In a study comparing the specificity of pulmonary arteriography and CTA, pulmonary arteriography was noted to have a higher specificity for detecting the angioarchitecture compared to CTA (100% versus 78%) [24]. Pulmonary angiography is performed as a part of the treatment procedure and does not have a standalone diagnostic role in detecting PAVM. An exception in which pulmonary angiogram would be helpful as an initial diagnostic imaging tool is in a patient who is hemodynamically unstable with clinical suspicion of pulmonary hemorrhage from a PAVM [25].


Pulmonary Arteriovenous Malformation PAVM . CT Chest With IV Contrast Contrast-enhanced CT chest offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Contrast-enhanced CT provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism [10,26]. Cross- sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. CT Chest Without and With IV Contrast There is limited data to support obtaining a CT chest with and without IV contrast in the setting of suspected PAVM. A study by Nawaz et al [24] compared CT with and without IV contrast to digital subtraction angiography (DSA) for assessment of PAVMs. Their study showed superior sensitivity of CT compared to DSA for detection of PAVM; however, the specificity for CT was inferior to that of DSA. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. The benefit of using CT chest without and with IV contrast for assessing PAVM compared to stand-alone CT without IV contrast or CT with IV contrast is unclear [24]. CT Chest Without IV Contrast Noncontrast chest CT scan is helpful in confirming the diagnosis of PAVM. Like CT chest with IV contrast, Noncontrast CT offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Remy et al [28] were able to predict angioarchitecture of the PAVMs in 95% of cases using noncontrast CT and 3-D reconstruction. Cross-sectional anatomy displayed on CT chest without IV contrast is useful in treatment planning [10,27]. CTA Chest With IV Contrast CTA chest provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM.


Pulmonary Arteriovenous Malformation PAVM . Adequate precaution should be taken to prevent air embolism. Unlike CTPA, the vascular enhancement during CTA is timed for the aorta and its branches and, thus, it may help identify systemic supply to PAVMs via the systemic arteries [10,29,30]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. CTA Pulmonary Arteries With IV Contrast CTPA specifically assesses the pulmonary vasculature. IV contrast material is timed for optimum evaluation of the pulmonary arteries. Use of CTPA for evaluation of PAVM is used in clinical practice when considering a contrast- enhanced CT scan for evaluating PAVM. Like other CT techniques, CTPA offers high special resolution and can detect the number, size, and distribution of PAVMs accurately. CTPA provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air [27]. Correlating the PAVM grade with contrast-enhanced echo has been shown to be more sensitive with CTPA compared to noncontrast CT [31]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. MRA Chest Without and With IV Contrast There is no role for the routine use of MRA chest without and with IV contrast in the workup of a patient suspected of a PAVM. MRA Chest Without IV Contrast There is no role for the routine use of MRA chest without IV contrast in the workup of a patient suspected of a PAVM. MRA Pulmonary Arteries Without and With IV Contrast Contrast-enhanced MRA pulmonary arteries provides anatomical information about the presence, number, size, and location of PAVMs. Schneider et al [32] evaluated 203 patients with HHT or first-degree relatives with HHT using contrast-enhanced MRA. Patients with definite and uncertain diagnosis of PAVM on MRA underwent pulmonary angiogram.


Pulmonary Arteriovenous Malformation PAVM . Pulmonary angiogram detected only 77% to 80% of the PAVMs that were seen on MRA. In their study, Pulmonary Arteriovenous Malformation (PAVM) the majority of the PAVMs not detected by pulmonary angiogram were <5 mm in size. The size criterion was defined as the size of the PAVM itself and not of the feeding artery. A more recent study by Van den Heuvel et al [33] investigated the sensitivity of contrast-enhanced MRA for detection of PAVMs with a feeding artery >2 cm in children and young adults. They enrolled 53 patients who had a TTCE grade 2 or 3 who underwent chest CT and were found to have the PAVM with a feeding artery >2 cm to receive a contrast-enhanced MRA. The sensitivity of contrast-enhanced MRA to detect PAVMs with a feeding artery size of >2cm was 92%, and the specificity ranged from 67% to 96%. MRA Pulmonary Arteries Without IV Contrast There is no role for the routine use of MRA pulmonary angiography without IV contrast in the workup of a patient suspected of a PAVM. Pertechnetate Albumin Pulmonary Scan There is no role for pertechnetate albumin pulmonary scan in a modern day practice. Historically, this technique was used to detect and quantify right to left shunting before and after treatment of a PAVM [34,35]. Radiography Chest The radiographic appearance of a lower lobe pulmonary nodule with a branching afferent artery and dilated efferent vein defines the classical appearance of PAVM on chest radiography. The sensitivity of chest radiography is 60% to 70% with a 98% specificity when the classical findings are present [36]. The afferent and efferent vasculature and smaller PAVMs may be difficult to see on a single-view chest radiograph. Best diagnostic results are obtained when a 2-view chest radiograph, posteroanterior view, and lateral view is performed [37]. The role of chest radiography in the diagnosis of a suspected PAVM is limited due to its poor sensitivity.


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transesophageal There is no role for TEE as a standalone diagnostic tool in the evaluation of PAVMs. The usefulness of TEE in the context of PAVM is to rule out intracardiac shunts [38]. Its ability to demonstrate the interatrial septum and the insertion of the pulmonary veins into the left atrium is useful to evaluate the anatomical variations [39]. US Echocardiography Transesophageal With IV Contrast TEE with IV agitated saline contrast material is not routinely used to diagnose PAVM. Contrast-enhanced TEE maybe helpful to locate a PAVM based on the excellent visualization of the 4 pulmonary venous ostia as veins drain into the left atrium. Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs is limited. US Echocardiography Transthoracic Resting There is no role for TTE in the resting phase for evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38]. US Echocardiography Transthoracic With IV Contrast TTCE is an essential diagnostic test for patients suspected of having a PAVM. TTCE with agitated saline has a 98% to 99% sensitivity and a 67% to 91% specificity for detecting PAVMs [41]. The microbubbles are visualized after 3 to 8 cardiac cycles in the left atrium after initial opacification of the right chambers in patients with an intrapulmonary shunt [1]. TTCE does not provide any information regarding the size and location of the PAVM. Based on the appearance of the bubbles in the left atrium a semiquantitative grading system has been developed [42,43]. The grades are defined as 0, with no opacification, grade 1 with <30 bubbles, grade 2 with moderate filling, and grade 3 with complete opacification of the left atrium.


Pulmonary Arteriovenous Malformation PAVM . The grading system correlates well with the diagnosis of PAVM, with higher grades associated with larger shunts and cerebral complications [41,44,45]. Usefulness of the grading system to predict treatment of PAVM demonstrates that grades 2 and 3 have a positive predictive value of 0.21 (95% CI, 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively [44]. Adverse events including air embolism are rare with TTCE occurring in <1% [46]. Variant 3: Asymptomatic with a family history of HHT and suspected PAVM. Initial imaging. Arteriography Pulmonary The real-time nature of pulmonary arteriography allows for high accuracy in delineating the angioarchitecture and detection of flow characteristics such as the early draining vein. In a study comparing the specificity of pulmonary arteriography and CTA, pulmonary arteriography was noted to have a higher specificity for detecting the Pulmonary Arteriovenous Malformation (PAVM) angioarchitecture compared to CTA (100% versus 78%) [24]. Pulmonary angiography is performed as a part of the treatment procedure and does not have a standalone diagnostic role in detecting PAVM. CT Chest With IV Contrast Contrast-enhanced CT chest offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Contrast-enhanced CT provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism [10,26]. Cross- sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. CT Chest Without and With IV Contrast There is limited data to support obtaining a CT chest with and without IV contrast in the setting of suspected PAVM.


Pulmonary Arteriovenous Malformation PAVM . A study by Nawaz et al [24] compared CT with and without IV contrast to DSA for assessment of PAVMs. Their study showed superior sensitivity of CT compared to DSA for detection of PAVM; however, the specificity for CT was inferior to that of DSA. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. The benefit of using CT chest without and with IV contrast for assessing PAVM compared to stand-alone CT without IV contrast or CT with IV contrast is unclear [24]. CT Chest Without IV Contrast Noncontrast chest CT scan is helpful in confirming the diagnosis of PAVM. Like CT chest with IV contrast, noncontrast CT offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Remy et al [28] were able to predict angioarchitecture of the PAVMs in 95% of cases using noncontrast CT and 3- D reconstruction. Cross-sectional anatomy displayed on CT chest without IV contrast is useful in treatment planning [10,27]. CTA Chest With IV Contrast CTA chest provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism. Unlike CTPA, the vascular enhancement during CTA is timed for the aorta and its branches and, thus, it may help identify systemic supply to PAVMs via the systemic arteries [10,29,30]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. CTA Pulmonary Arteries With IV Contrast CTPA specifically assesses the pulmonary vasculature. IV contrast material is timed for optimum evaluation of the pulmonary arteries. Use of CTPA for evaluation of PAVM is used in clinical practice when considering a contrast- enhanced CT scan for evaluating PAVM.


Pulmonary Arteriovenous Malformation PAVM . Like other CT techniques, CTPA offers high special resolution and can detect the number, size, and distribution of PAVMs accurately. CTPA provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air [27]. Correlating the PAVM grade with contrast-enhanced echo has been shown to be more sensitive with CTPA compared to noncontrast CT [31]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. MRA Chest Without and With IV Contrast There is no role for the routine use of MRA chest without and with IV contrast in the workup of a patient suspected of a PAVM. MRA Chest Without IV Contrast There is no role for the routine use of MRA chest without IV contrast in the workup of a patient suspected of a PAVM. MRA Pulmonary Arteries Without and With IV Contrast Contrast-enhanced MRA pulmonary arteries provides anatomical information about the presence, number, size, and location of PAVMs. Schneider et al [32] evaluated 203 patients with HHT or first-degree relatives with HHT using contrast-enhanced MRA. Patients with definite and uncertain diagnosis of PAVM on MRA underwent pulmonary angiogram. Pulmonary angiogram detected only 77% to 80% of the PAVMs that were seen on MRA. In their study, the majority of the PAVMs not detected by pulmonary angiogram were <5 mm in size. The size criterion was defined as the size of the PAVM itself and not of the feeding artery. A more recent study by Van den Heuvel et al Pulmonary Arteriovenous Malformation (PAVM) [33] investigated the sensitivity of contrast-enhanced MRA for detection of PAVMs with a feeding artery >2 cm in children and young adults.


Pulmonary Arteriovenous Malformation PAVM . They enrolled 53 patients who had a TTCE grade 2 or 3 who underwent chest CT and were found to have the PAVM with a feeding artery >2 cm to receive a contrast-enhanced MRA. The sensitivity of contrast-enhanced MRA to detect PAVMs with a feeding artery size of >2cm was 92%, and the specificity ranged from 67% to 96%. MRA Pulmonary Arteries Without IV Contrast There is no role for the routine use of MRA pulmonary angiography without IV contrast in the workup of a patient suspected of a PAVM. Pertechnetate Albumin Pulmonary Scan There is no role for pertechnetate albumin pulmonary scan in a modern day practice. Historically, this technique was used to detect and quantify right to left shunting before and after treatment of a PAVM [34,35]. Radiography Chest The radiographic appearance of a lower lobe pulmonary nodule with a branching afferent artery and dilated efferent vein defines the classical appearance of PAVM on chest radiography. The sensitivity of chest radiography is 60% to 70% with a 98% specificity when the classical findings are present [36]. The afferent and efferent vasculature and smaller PAVMs may be difficult to see on a single-view chest radiograph. Best diagnostic results are obtained when a 2-view chest radiograph, posteroanterior view, and lateral view is performed [37]. US Echocardiography Transesophageal There is no role for TEE as a standalone diagnostic tool in the evaluation of PAVMs. The usefulness of TEE in the context of PAVM is to rule out intracardiac shunts [38]. Its ability to demonstrate the interatrial septum and the insertion of the pulmonary veins into the left atrium is useful to evaluate the anatomical variations [39]. US Echocardiography Transesophageal With IV Contrast TEE with IV agitated saline contrast material is not routinely used to diagnose PAVM. Contrast-enhanced TEE may be helpful to locate a PAVM based on the excellent visualization of the 4 pulmonary venous ostia as veins drain into the left atrium.


Pulmonary Arteriovenous Malformation PAVM . Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs is limited. US Echocardiography Transthoracic Resting There is no role for TTE in the resting phase for the evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38]. US Echocardiography Transthoracic With IV Contrast TTCE is an essential diagnostic test for patients suspected of having a PAVM. TTCE with agitated saline has a 98% to 99% sensitivity and a 67% to 91% specificity for detecting PAVMs [41]. The microbubbles are visualized after 3 to 8 cardiac cycles in the left atrium after initial opacification of the right chambers in patients with an intrapulmonary shunt [1]. TTCE does not provide any information regarding the size and location of the PAVM. Based on the appearance of the bubbles in the left atrium a semiquantitative grading system has been developed [42,43]. The grades are defined as 0 with no opacification, grade 1 with <30 bubbles, grade 2 with moderate filling, and grade 3 with complete opacification of the left atrium. The grading system correlates well with the diagnosis of PAVM, with higher grades associated with larger shunts and cerebral complications [41,44,45]. Usefulness of the grading system to predict treatment of PAVM demonstrates that grades 2 and 3 have a positive predictive value of 0.21 (95% CI, 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively [44]. Adverse events including air embolism are rare with TTCE occurring in <1% [46]. Variant 4: Presenting to establish care with a past history of a treated PAVM. Follow-up (surveillance) imaging following embolization of PAVM.


Pulmonary Arteriovenous Malformation PAVM . Arteriography Pulmonary The real-time nature of pulmonary arteriography allows for high accuracy for delineating the angioarchitecture and detection of flow characteristics such as the early draining vein. Pulmonary angiogram is the reference standard to detect reperfusion of a treated AVM, but the angiogram is performed as a part of the treatment protocol and not done as a diagnostic test [10]. In patients who have inconclusive findings on CT, pulmonary angiography can assess recanalized PAVMs. Pulmonary Arteriovenous Malformation (PAVM) CT Chest With IV Contrast The high natural contrast inherent to pulmonary anatomy on noncontrast CT and the small risk of air embolism while administering IV medications renders CT chest with IV contrast unnecessary in the diagnosis of PAVM [10]. Artifacts from the embolic material limits the usefulness of contrast enhancement as a tool to evaluate reperfusion [47]. The role of contrast-enhanced CT has been studied after embolotherapy for PAVM in the context of detecting systemic collaterals by Brillet et al [29] in 32 patients. They found systemic collaterals in 13 patients that would otherwise have been missed on noncontrast CT. The role of contrast-enhanced CT scan after PAVM embolization is unclear. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in further treatment planning if new or recanalized PAVMs are detected [10,27]. CT Chest Without and With IV Contrast The high natural contrast inherent to pulmonary anatomy on noncontrast CT and the small risk of air embolism while administering IV medications renders CT chest with IV contrast unnecessary in the diagnosis of PAVM [10]. Artifacts from the embolic material limits the usefulness of contrast enhancement as a tool to evaluate reperfusion [47]. The role of contrast-enhanced CT has been studied after embolotherapy for PAVM in the context of detecting systemic collaterals by Brillet et al [29] in 32 patients.


Pulmonary Arteriovenous Malformation PAVM . They found systemic collaterals in 13 patients that would otherwise have been missed on noncontrast CT. The role of contrast-enhanced CT scan after PAVM embolization is unclear. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in further treatment planning if new or recanalized PAVMs are detected [10,27]. CTA Chest With IV Contrast CTA also provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. Contrast administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism. CTA may help identify systemic supply to large PAVMs via the systemic arteries [10,29,30]. Artifacts from the embolic material limit the usefulness of contrast enhancement as a tool to evaluate the reperfusion [47]. The role of contrast-enhanced CT has been studied after embolotherapy for PAVM in the context of detecting systemic collaterals by Brillet et al [29] in 32 patients. They found systemic collaterals in 13 patients that would otherwise have been missed on noncontrast CT. Another study by Remy-Jardin et at [30] showed that long-term CTA follow-up of initially successfully treated PAVMs revealed successful embolotherapy of 75% and partially or completely failed embolotherapy of 25% of PAVMs. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in further treatment planning if new or recanalized PAVMs are detected [10,27]. CTA Pulmonary Arteries With IV Contrast CTPA specifically assesses the pulmonary vasculature. IV contrast is timed for optimum evaluation of the pulmonary arteries. Although, there is limited literature specific to CTA of pulmonary arteries for evaluation of PAVM. This protocol is used in clinical practice when considering contrast-enhanced CT scan for evaluating PAVM. Like other CT techniques, CTPA offers high special resolution and can detect the number, size, and distribution of PAVMs accurately.


Pulmonary Arteriovenous Malformation PAVM . CTPA provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air [27]. Correlating the PAVM grade with contrast-enhanced echo has been shown to be more sensitive with CTPA compared to noncontrast CT [31]. Strategies to mitigate the artifacts from embolic material by adjusting scan parameters and using dual-energy and spectral CT acquisition have shown promise in other anatomical locations. For instance, Zheng et al [54] showed Pulmonary Arteriovenous Malformation (PAVM) that spectral CT using metal artifact reduction software improved vascular evaluation of adjacent metallic coils in the brain. Visualization of recanalized flow remains a challenge in posttreatment CT evaluation for reperfusion. MRA Chest Without and With IV Contrast There is no role for the routine use of MRA chest without and with IV contrast in the workup of a patient with treated PAVM. MRA Chest Without IV Contrast There is no role for the routine use of MRA chest without IV contrast in the workup of a patient with treated PAVM. MRA Pulmonary Arteries Without and With IV Contrast Dynamic MRA using time-resolved sequences has the advantage over CT, and it is not affected by the artifact from the embolic material. Time-resolved MRA can detect flow in the pulmonary vein similar to pulmonary arteriography. Shimohira et al [55] compared the sensitivity and specificity of CT and time-resolved MRA with digital subtraction angiography as a reference standard in a multi-institutional retrospective cohort of 205 patients. Using 55% as the threshold reduction of the sac diameter on CT, they found a sensitivity and specificity for CT at 82% and 81%, respectively. Time-resolved MRA on the other hand has a sensitivity and specificity of 89% and 95%, respectively.


Pulmonary Arteriovenous Malformation PAVM . Similar findings have been reported in 28 PAVMs in 10 patients by Kawai et al [56]. In a recent study, Hong et al [57] studied the feasibility of time-resolved MRA in evaluating the feeding arteries and reperfusion after embolization of PAVMs in 9 patients with 62 PAVMs. They found a sensitivity and specificity of 100% for detection of reperfusion compared to catheter angiography as the reference standard. The visibility of the feeding arteries was compared to CT, and they found good correlation between 0.76 and 0.79 with 2 readers when using 3- D maximum intensity projection images. Time-resolved MRA also has the advantage of detecting reperfusion after repeat embolization for persistence as the burden of coiling will be greater leading to more metallic artifacts on CT [58]. MRA Pulmonary Arteries Without IV Contrast There is no role for the routine use of MRA pulmonary angiography without IV contrast in the workup of a patient with treated PAVM. Radiography Chest The radiographic appearance of a lower lobe pulmonary nodule with a branching afferent artery and dilated efferent vein defines the classical appearance of PAVM on chest radiography. The sensitivity of chest radiography is 60% to 70% with a 98% specificity when the classical findings are present [36]. The afferent and efferent vasculature and smaller PAVMs may be difficult to see on a single-view chest radiograph. Best diagnostic results are obtained when a 2-view chest radiograph, posteroanterior view, and lateral view is performed [37]. Chest radiography has limited usefulness to detect recurrent disease in the setting of prior treated PAVM. US Echocardiography Transesophageal There is no role for TEE as a standalone diagnostic tool in the evaluation of PAVMs. The usefulness of TEE in the context of PAVM is to rule out intracardiac shunts [38]. Its ability to demonstrate the interatrial septum and the insertion of the pulmonary veins into the left atrium is useful to evaluate the anatomical variations [39].


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transesophageal With IV Contrast TEE with IV agitated saline contrast material is not routinely used to diagnose PAVM. Contrast-enhanced TEE maybe helpful to locate a PAVM based on the excellent visualization of the 4 pulmonary venous ostia as veins drain into the left atrium. Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs may be limited. US Echocardiography Transthoracic Resting There is no role for TTE in the resting phase for evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38]. US Echocardiography Transthoracic With IV Contrast TTCE is an essential diagnostic test for patients suspected of having a PAVM. TTCE with agitated saline has a 98% to 99% sensitivity and a 67% to 91% specificity for detecting PAVMs [41]. The microbubbles are visualized after 3 to 8 cardiac cycles in the left atrium after initial opacification of the right chambers in patients with an intrapulmonary shunt [1]. TTCE does not provide any information regarding the size and location of the PAVM. Based on the appearance of the bubbles in the left atrium a semiquantitative grading system has been developed Pulmonary Arteriovenous Malformation (PAVM) [42,43]. The grades are defined as 0 with no opacification, grade 1 with <30 bubbles, grade 2 with moderate filling, and grade 3 with complete opacification of the left atrium. The grading system correlates well with the diagnosis of PAVM, with higher grades associated with larger shunts and cerebral complications [41,44,45]. Usefulness of the grading system to predict treatment of PAVM demonstrates that grades 2 and 3 have a positive predictive value of 0.21 (95% CI, 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively [44].


Pulmonary Arteriovenous Malformation PAVM . Adverse events including air embolism are rare with TTCE occurring in <1% [46]. However, as a tool to measure the effectiveness of prior treatment, TTCE has low specificity and sensitivity. Variant 5: Asymptomatic with abnormal imaging on CT or chest radiography suggestive of PAVM. Next imaging study. Arteriography Pulmonary The real-time nature of pulmonary arteriography allows for high accuracy in delineating the angioarchitecture and detection of flow characteristics such as the early draining vein. In a study comparing the specificity of pulmonary arteriography and CTA, pulmonary arteriography was noted to have a higher specificity for detecting the angioarchitecture compared to CTA (100% versus 78%) [24]. Pulmonary angiography is performed as a part of the treatment procedure and does not have a standalone diagnostic role in detecting PAVM. An exception where pulmonary angiogram would be helpful as an initial diagnostic imaging tool is in a patient who is hemodynamically unstable with clinical suspicion of pulmonary hemorrhage from a PAVM [25]. CT Chest With IV Contrast Contrast-enhanced CT chest offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Contrast-enhanced CT provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism [10,26]. Cross- sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. CT Chest Without and With IV Contrast There is limited data to support obtaining a CT chest with and without IV contrast in the setting of suspected PAVM.


Pulmonary Arteriovenous Malformation PAVM . A study by Nawaz et al [24] compared CT with and without IV contrast to DSA for assessment of PAVMs. Their study showed superior sensitivity of CT compared to DSA for detection of PAVM; however, the specificity for CT was inferior to that of DSA. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. The benefit of using CT chest without and with IV contrast for assessing PAVM compared to stand-alone CT without IV contrast or CT with IV contrast is unclear [24]. CT Chest Without IV Contrast Noncontrast chest CT scan is helpful in confirming the diagnosis of PAVM. Like CT chest with IV contrast, Noncontrast CT offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Remy et al [28] were able to predict angioarchitecture of the PAVMs in 95% of cases using noncontrast CT and 3-D reconstruction. Cross-sectional anatomy displayed on CT chest without IV contrast is useful in treatment planning [10,27]. CTA Chest With IV Contrast CTA chest also provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism. Unlike CTPA, the vascular enhancement during CTA is timed for the aorta and its branches, and, thus, it may help identify systemic supply to PAVMs via the systemic arteries [10,29,30]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. CTA Pulmonary Arteries With IV Contrast CTPA specifically assesses the pulmonary vasculature. IV contrast material is timed for optimum evaluation of the pulmonary arteries. Use of CTPA for evaluation of PAVM is used in clinical practice when considering a contrast- enhanced CT scan for evaluating PAVM.


Pulmonary Arteriovenous Malformation PAVM . Like other CT techniques, CTPA offers high special resolution and can detect the number, size, and distribution of PAVMs accurately. CTPA provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air [27]. Correlating the PAVM grade with contrast-enhanced echo has been shown to be more sensitive with CTPA Pulmonary Arteriovenous Malformation (PAVM) compared to noncontrast CT [31]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. MRA Chest Without and With IV Contrast There is no role for the routine use of MRA chest without and with IV contrast in the workup of a patient suspected of a PAVM. MRA Chest Without IV Contrast There is no role for the routine use of MRA chest without IV contrast in the workup of a patient suspected of a PAVM. MRA Pulmonary Arteries Without and With IV Contrast Contrast-enhanced MRA pulmonary arteries provides anatomical information about the presence, number, size, and location of PAVMs. Schneider et al [32] evaluated 203 patients with HHT or first-degree relatives with HHT using contrast-enhanced MRA. Patients with definite and uncertain diagnosis of PAVM on MRA underwent pulmonary angiogram. Pulmonary angiogram detected only 77% to 80% of the PAVMs that were seen on MRA. In their study, the majority of the PAVMs not detected by pulmonary angiogram were <5 mm in size. The size criterion was defined as the size of the PAVM itself and not of the feeding artery. A more recent study by Van den Heuvel et al [33] investigated the sensitivity of contrast-enhanced MRA for detection of PAVMs with a feeding artery >2 cm in children and young adults.


Pulmonary Arteriovenous Malformation PAVM . They enrolled 53 patients who had a TTCE grade 2 or 3 who underwent chest CT and were found to have the PAVM with a feeding artery >2 cm to receive a contrast-enhanced MRA. The sensitivity of contrast-enhanced MRA to detect PAVMs with a feeding artery size of >2cm was 92%, and the specificity ranged from 67% to 96%. MRA Pulmonary Arteries Without IV Contrast There is no role for the routine use of MRA pulmonary angiography without IV contrast in the workup of a patient suspected of a PAVM. US Echocardiography Transesophageal There is no role for TEE as a standalone diagnostic tool in the evaluation of PAVMs. The usefulness of TEE in the context of PAVM is to rule out intracardiac shunts [38]. Its ability to demonstrate the interatrial septum and the insertion of the pulmonary veins into the left atrium is useful to evaluate the anatomical variations [39]. US Echocardiography Transesophageal With IV Contrast TEE with IV agitated saline contrast material is not routinely used to diagnose PAVM. Contrast-enhanced TEE maybe helpful to locate a PAVM based on the excellent visualization of the 4 pulmonary venous ostia as veins drain into the left atrium. Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs may be limited. US Echocardiography Transthoracic Resting There is no role for TTE in the resting phase for the evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38]. Pulmonary Arteriovenous Malformation (PAVM) Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch. acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs.  Introduction/Background Fractures of the proximal femur (commonly referred to as hip fractures) are a frequent source of morbidity and mortality in elderly osteoporotic patients [1]. Typically the result of a ground-level fall, fractures of this type result in approximately 300,000 hospitalizations per year and are nearly twice as common in women as in men [2,3]. As the United States population continues to age, the incidence of hip fractures and associated medical costs will continue to rise, predicted to reach $18 billion by 2025 [4]. Patients suffer a substantial decline in quality of life following a hip fracture [5] as well as a 1-year mortality rate of 22% for women and 33% for men [1]. Delays in diagnosis and treatment are associated with increased cost, complication rate, length of hospital stay, and short- and long-term mortality [6-13]. Therefore, rapid diagnosis and treatment of hip fractures is critical. Hip fractures cannot be reliably diagnosed or excluded on the basis of physical examination alone; therefore, imaging plays a key role in early and accurate diagnosis [14]. Treatment for both intra- and extracapsular proximal femoral fractures in the elderly is typically surgical fixation because of the risk of further fracture displacement and the dangers of prolonged immobilization in the elderly [15]. Joint replacement may be performed for displaced fractures of the femoral neck where the risk of femoral head avascular necrosis is high. Fractures from high-force trauma are also commonly treated with surgical fixation for stability to reduce the risk of post-traumatic osteoarthritis. Reprint requests to: publications@acr.org Acute Hip Pain-Suspected Fracture Multiple studies have demonstrated that radiographs have limited sensitivity for fracture detection of the proximal femur, particularly in elderly osteoporotic patients [20-24].


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. All of these studies constitute retrospective series in which patients with negative radiographs but high clinical suspicion went on to receive a MRI scan at the discretion of the evaluating clinician. In one such study, 14% of patients with negative radiographs were found to have fractures of the hip or pelvis [23]. In this same study, Kirby et al [23] also reported 12% of patients with suspicious radiographs were found to have no fracture on MRI, illustrating limitations in the specificity of radiographs as well. Other studies have had more dramatic results, with Sankey et al [25] reporting 83 of 98 patients to have fractures after negative radiographs, 23 of whom required operative management. The variability is likely due to differing proportions of patients going on to MRI following negative radiographs in these retrospective studies. However, there is no accepted clinical decision rule to guide when patients with suspected hip fracture should have advanced imaging after negative radiographs. A new inability to bear weight is a clinically suspicious finding, although the sensitivity and specificity of this is unknown [20]. Allowing for variation between studies, the estimated prevalence of occult fracture after negative radiographs has been estimated at 4% to 10%, indicating the inability of negative radiographs alone to exclude fracture [21,26]. Risk factors for radiographically occult fracture in these studies included those age >65, low-force trauma, such as a ground-level fall, and female gender. These studies have almost exclusively included elderly patients. There is no relevant literature regarding the sensitivity and specificity of radiographs in the younger patient population, and clinicians are suggested to proceed with caution. Radiography Pelvis There is no specific literature regarding the use of an AP view of the pelvis alone for acute hip pain following low-force trauma.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Previous literature regarding the accuracy of radiography has almost exclusively evaluated AP and cross-table lateral radiographs of the hip or the combined use of AP pelvis and hip radiographs. However, it is well established that patients with clinically suspected proximal femur fracture often have fractures of the pelvis, including the sacrum and pubic rami [21,27-30]. Therefore, it has been recommended that the radiographic series include the AP view of the pelvis along with the orthogonal views of the symptomatic hip [31]. The inclusion of a pelvis radiograph also allows for comparison of potential abnormalities to the contralateral asymptomatic side. Pelvis radiographs share the same limitations in sensitivity and specificity for fracture detection as hip radiographs, and a negative radiograph alone cannot exclude fracture. Radiography Pelvis and Hip As previously discussed, patients with clinically suspected proximal femur fracture often have fractures of the pelvis that include the sacrum and pubic rami [21,27-30]. Moreover, these pelvic fractures may occur in isolation or concomitant with a fracture of the proximal femur [28]. Therefore, it has been recommended that the radiographic series include both the AP view of the pelvis along with orthogonal views of the symptomatic hip [31]. The inclusion of a pelvis radiograph also allows for comparison of potential abnormalities to the contralateral asymptomatic side. For these reasons, an AP view of the pelvis with a cross-table lateral view of the symptomatic hip is the standard approach at many institutions, whereas some will include three views: an AP view of the pelvis, a separate AP view of the symptomatic hip, and the cross-table lateral view. There is no specific literature to compare these two approaches.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Although they remain the mainstay for initial imaging, pelvis and hip radiographs share the same limitations in sensitivity and specificity for fracture detection, and negative radiographs alone cannot exclude fracture. MRI Pelvis and Affected Hip At least 90% of proximal femoral fractures will be identified on radiographs [21]. Therefore, MRI without intravenous (IV) contrast is reserved for second-line imaging in instances of negative radiographs with continued clinical suspicion for fracture rather than as a first-line modality. Acute Hip Pain-Suspected Fracture The use of contrast-enhanced MRI has been explored as a technique to assess femoral head perfusion in cases of proximal femoral fracture [32,33], but this modality does not play a role in initial imaging assessment. CT Pelvis and Hips Although not as sensitive as MRI, noncontrast CT is also reserved as a problem-solving modality following radiography either to evaluate for radiographically occult fracture or to better depict fracture morphology for treatment planning purposes [34,35]. There is no relevant literature to support the use of contrast-enhanced CT as an initial imaging modality in instances of acute hip pain following low-force trauma. There is no relevant literature to support the use of multiphase CT as an initial imaging modality in instances of acute hip pain following low-force trauma. US Hip Although there has been limited investigation into the use of ultrasound (US) for hip fracture detection, US does not play a role as the initial imaging in this setting [36]. Bone Scan Hips There is no relevant literature to support the use of a nuclear medicine bone scan as an initial imaging modality in instances of acute hip pain following low-force trauma. Variant 2: Acute hip pain. Fall or minor trauma. Negative radiographs. Suspect fracture. Next imaging study.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. MRI Pelvis and Affected Hip There is considerable literature regarding the use of noncontrast MRI for the detection of radiographically occult proximal femoral fractures. An early study by Quinn et al [37] found MRI to be 100% accurate for fracture detection in patients with indeterminate radiographs using clinical outcomes as the gold standard. A subsequent study by Pandey et al [38] found no missed fractures in 10 of 33 patients with negative MRIs, all of whom were followed clinically for at least 6 months. A 2008 study showed 99% sensitivity of MRI, both for proximal femoral fractures and fractures of the pelvis [39]. With multiple studies indicating near 100% sensitivity for proximal femoral fracture, it has been suggested that a negative MRI may allow for confident discharge from the emergency department and reduce the number of cautionary admissions [23,29]. Conversely, rapid diagnosis of surgical fractures reduces delay to treatment with associated improved outcomes [10]. Several additional studies have also shown high diagnostic accuracy for diagnosis of both pelvis fractures and soft-tissue injuries in addition to fractures of the proximal femur [28,30,39]. This versatility is important as many series have shown a high incidence of extrafemoral trauma in patients with acute hip pain and negative radiographs. For example, in the study by Ohishi et al [30], of 113 patients, 38% had fractures of the proximal femur and 33% had fractures of the pelvis. In another retrospective series, Dominguez et al [21] found pelvic fractures to be more common than proximal femur fractures in this patient population, emphasizing the importance of accuracy in the assessment of extrafemoral trauma. Although many of these pelvic fractures and soft-tissue injuries may not be treated surgically, correct diagnosis allows for appropriate conservative treatment, including protected weight-bearing, pain control, deep vein thrombosis prophylaxis, and skilled rehabilitation.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. In addition to its increased sensitivity for fracture detection, MRI has been shown to be useful in characterizing fracture morphology. Seemingly isolated fractures of the greater trochanter diagnosed on radiography frequently have intertrochanteric extension when evaluated with MRI [22]. In a classic study of 30 patients, Schultz et al [40] demonstrated the use of MRI to accurately depict the extent of the fracture line in these radiographically occult intertrochanteric fractures. There is an increasing trend to treat incomplete intertrochanteric fractures conservatively. For example, in a small series of 8 patients, Alam et al [41] found that of the 5 patients treated conservatively, none went on to complete their fracture. Several authors have suggested that with its ability to depict fracture morphology with accuracy, MRI may have a continued role to play in directing treatment [22,40]. Specific scanning protocols have emphasized either speed or comprehensiveness. A 2003 study of 93 cases found 100% sensitivity for the coronal short tau inversion-recovery (STIR) sequence alone [42], and a more recent study found 99% sensitivity of the coronal STIR sequence with increasing confidence and specificity with the addition of a coronal T1 sequence [43]. Given the increasing throughput pressures in the emergency department and the Acute Hip Pain-Suspected Fracture difficulty of older patients in tolerating long scan times, there continues to be interest in developing rapid and accurate MRI protocols. With the diagnostic accuracy of noncontrast MRI approaching 100%, there has been little need to explore the addition of IV gadolinium contrast solely for the purposes of fracture detection. Rather, the interest has been in the use of dynamic MRI to evaluate femoral head perfusion for prognostic purpose to estimate the risks of impaired perfusion, such as osteonecrosis and nonunion.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. In one study of 36 patients, impaired femoral head perfusion was more common in patients with displaced fractures, although there was considerable overlap of perfusion pattern and fracture type [44]. The accuracy of predicting successful osseous union was 75% based on fracture morphology and improved incrementally to 89% on the basis of perfusion dynamics. Only 2 of 16 patients with nondisplaced fractures had osteonecrosis. A study from 2009 had similar results with 90% accuracy for prediction of successful fracture union on the basis of femoral head perfusion [45]. However, the study identified only 1 patient with a nondisplaced fracture with impaired femoral head perfusion and did not specify whether this patient went on to osteonecrosis, nor was the accuracy of predicting osteonecrosis on the basis of femoral head perfusion compared to that of the well-established Garden classification system. Given these findings, it is not clear if contrast-enhanced MRI offers significant advantages in the evaluation of the fractured hip compared to existing classification systems. CT Pelvis and Hips CT has advantages over MRI in terms of speed as well as use in patients with significant confusion. There has been considerable investigation into the accuracy of noncontrast CT for detection of radiographically occult proximal femoral fractures, although these studies have been invariably retrospective in nature, have used inconsistent methodology, and at times produced conflicting results. In one study of 199 patients, CT was negative for fracture in 93 patients, and none were found to have undiscovered fractures at 4-month clinical follow-ups [34]. Another similar study with 68 patients found no missed fractures in 27 patients with negative CT scans, although it was not clear if clinical follow-up was as comprehensive [46]. However, a number of other studies have demonstrated potential limitations in the sensitivity of CT.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. For example, Haubro et al [26] found a sensitivity for CT of 87% compared with 100% for MRI, with CT missing 6 of 15 fractures. Another larger study of 129 cases compared MRI and CT for the diagnosis of both proximal femoral and pelvic fractures and found a sensitivity of 99% for MRI and 69% for CT using clinical outcomes and follow-up imaging as the gold standard [39]. This same study by Cabarrus et al [39] also found MRI to be substantially better at detecting soft-tissue abnormalities with 99% sensitivity for MRI and 13% sensitivity edema, and the differences in sensitivity for more significant injuries, such as hematoma or tendon avulsion, may be somewhat less. Several other similar studies comparing CT and MRI have also shown decreased sensitivity of CT with potential for missed fractures as well as changes in diagnosis and management when MRI is obtained after CT [24,47,48]. There is no relevant data to support the use of contrast-enhanced CT solely for the purpose of fracture detection following negative radiographs. However, if contrast-enhanced CT examination of the abdomen and pelvis is performed because of suspicion of concurrent intra-abdominal trauma, bone algorithm reconstruction of the pelvis and hips may be performed rather than performing a separate examination. There is no relevant data to support the use of multiphase CT for the detection of fractures of the pelvis and proximal femur. Dual-energy CT is a more recent technology that has the ability to produce virtual noncalcium images for the detection of bone marrow edema. Although the technology holds promise, diagnostic accuracy does not yet approach that of MRI, with an initial study by Reddy et al [49] demonstrating a sensitivity of 90% and specificity of 40% for nondisplaced femoral neck fractures. However, this may be a modality of emerging importance as technology improves.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. US Hip The use of US for evaluation of the acutely painful hip has been evaluated in a single study of 10 patients with hip fractures [36]. Although US was able to identify trauma-related changes, such as joint effusion, with 100% sensitivity, specificity for fracture reached only 65%. The authors acknowledged that performance might further decrease for examinations performed by sonographers and radiologists not experienced with musculoskeletal US. For this document, it is assumed the procedure is performed and interpreted by an expert. Given the inability of US to comprehensively evaluate the bones and soft tissues of the pelvis, there is not enough evidence to support the role of US in the workup of radiographically occult hip fracture. Acute Hip Pain-Suspected Fracture Bone Scan Hips Prior to the advent of MRI, a bone scan was the preferred test for radiographically occult proximal femoral fractures. However, as early as 1993, Rizzo et al [50] demonstrated MRI to be at least as accurate as bone scans and with substantially decreased time to diagnosis. A later study by Rubin et al [51] comparing bone scans and MRI demonstrated improved sensitivity and specificity of MRI relative to bone scans. Moreover, the bone scan group averaged an additional day to surgery. Bone scintigraphy is a time-consuming process. Bone scans may be falsely negative for up to 72 hours from the time of injury, and false-positive scans are likewise common, related to osteoarthritis, soft-tissue injury, or any other process that may increase bone turnover [50]. It has been postulated that performing single-photon emission computed tomography may combine the sensitivity of bone scintigraphy with the spatial accuracy of CT, but there are no data to support this view. In current practice, the role of bone scans as a secondary line of imaging in patients with contraindications to MRI has largely been usurped by CT.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs.  Introduction/Background Stress fractures occur in 2 varieties: 1) fatigue fractures resulting from repetitive submaximal stress on normal bone, resulting in a region of accelerated bone remodeling [1] and 2) insufficiency fractures due to normal activity on bones that are deficient in microstructure and/or mineralization [2]. At the microscopic level, repetitive overloading leads to increased osteoclastic activity that exceeds the rate of osteoblastic new bone formation. This results in bone weakening and microtrabecular disruption (stress injury) and eventually may lead to a cortical break (stress fracture). Stress fractures are encountered frequently and account for up to 20% of all injuries seen in sports medicine clinics [1,3-6]. The fatigue variation of stress fractures are particularly common in athletes participating in activities that require running and jumping, as well as in ballet dancers and military recruits [7-9]. Certain medical interventions such as radiation therapy and long-term osteoporosis treatment with bisphosphonates predispose patients to the insufficiency variation of stress fractures [10-12]. OR Discussion of Procedures by Variant Variant 1: Adult. Suspect stress fracture, excluding vertebrae. Initial imaging. Area of Interest: pelvis, ankle, elbow, femur, foot, forearm, hand, hip, humerus, knee, leg tib/fib, ribs, sacrum, shoulder, or wrist. In the setting of new or repetitive athletic activity, fatigue fractures can develop in patients with normal bone. Furthermore, certain athletic activities often result in specific sites of fatigue fracture, such as olecranon process fractures in javelin throwers and baseball pitchers, proximal femur and tibial stress fractures in runners, and tarsal navicular stress fractures in basketball players [13-15]. Insufficiency fractures occur in patients with abnormal bone, be it from osteoporosis or irradiated bone, as typical examples.