Rib Fractures

Rib Fractures. Rib Fractures ventilation and compromise recovery. It should be noted that many of these patients are examined with portable supine radiography, which may contribute to underdiagnosis.


Rib Fractures

Rib Fractures. Radiography Rib Views There is no strong indication in the literature that radiography rib series serves any significant use as an initial imaging modality to detect rib fractures after CPR.


Rib Fractures

Rib Fractures. US Chest While focused US of the chest wall is more sensitive for detection of rib fractures than radiography in trauma patients [28], there is no direct evidence assessing the use of US in patients after CPR.


Rib Fractures

Rib Fractures. Bone Scan Whole Body There is no strong indication in the literature that bone scan serves any significant use as an initial imaging modality to detect rib fractures after CPR.


Rib Fractures

Rib Fractures. CT Chest As described above, chest CT is more sensitive than radiography for the detection of rib fractures after CPR. Moreover, CT may show fracture-related complications that are radiographically occult. Kim et al [33] reported that CT found fracture-related complications in 6 of 40 patients (15%) who received CPR, including 1 pneumothorax, 1 subclavian vein injury, and 4 chest wall hematomas. This study did not indicate whether intravenous (IV) contrast was used, nor did it indicate whether CT was performed specifically for evaluation of rib fractures, or if the rib fractures were an incidental finding on a CT performed for other means (eg, suspected pulmonary embolism).


Rib Fractures

Rib Fractures. Variant 3: Suspected pathologic rib fracture. Initial imaging. Radiography Chest Pathologic fractures may result from metabolic disorders or neoplasm, including primary bone tumor, metastatic disease of intrathoracic or extrathoracic primary, hematologic malignancy (eg, multiple myeloma, lymphoma), or direct extension of a tumor in the thorax. A PA chest radiograph may be sufficient for diagnosis of a pathologic fracture (or provide clues to an underlying diagnosis), but further evaluation using such modalities as CT, bone scan, or FDG-PET may be necessary to further characterize a lesion detected on radiography or to search for radiographically occult lesions [36-38].


Rib Fractures

Rib Fractures. Radiography Rib Views There is no strong indication in the literature that radiography rib series serves any significant use as an initial imaging modality to detect suspected pathologic rib fractures.


Rib Fractures

Rib Fractures. US Chest There is no strong indication in the literature that US serves any significant use as an initial imaging modality to detect rib fractures.


Rib Fractures

Rib Fractures. CT Chest CT may be useful for characterizing a pathologic fracture, and some features may be helpful in differentiating a primary malignant tumor of bone from metastasis [36]. CT may also be helpful to search for a primary malignancy in patients with a suspected pathologic fracture; however, there is no strong indication that CT serves a significant use as the initial imaging modality to detect pathologic rib fractures.


Rib Fractures

Rib Fractures. Bone Scan Whole Body Bone scans have a high sensitivity (>95%) but a low specificity for detection of pathologic rib fractures [30]. The distribution of abnormalities may serve as a useful clue in differentiating metastasis from post-traumatic fractures.


Rib Fractures

Rib Fractures. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT may be useful to further characterize a lesion detected on radiography or to search for radiographically occult lesions [36,37]. There is no strong indication in the literature that FDG-PET/CT should be the initial imaging modality to detect suspected pathologic rib fractures.


Rib Fractures

Rib Fractures. 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.


Rib Fractures

Rib Fractures. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Introduction/Background Axial spondyloarthritis or axial spondyloarthropathy (axSpA) describes a heterogeneous group of inflammatory disorders affecting the axial skeleton that were historically classified separately as ankylosing spondylitis (AS), reactive arthritis, psoriatic spondyloarthritis, enteropathic spondyloarthritis, juvenile spondyloarthritis, and undifferentiated spondyloarthritis [1]. The prevalence of axSpA is estimated to be between 0.9% to 1.4% in the United States adult population [2]. There is a genetic component to axSpA, including a strong association with HLA-B27, which is positive in 74% to 89% of patients [1]. Patients with axSpA often present before age 45 with chronic back pain and stiffness and may have elevated inflammatory markers [3]. A clinical hallmark is the presence of inflammatory back pain, which is present in 70% to 80% of patients [4]. There are varying definitions for inflammatory back pain, although characteristically this pain includes the following features: insidious onset, improvement with exercise, no improvement with rest, occurring at night, and age of onset <40 years of age [4]. Inflammatory back pain symptoms, depending on the criteria used, have been reportedly been present in 5% to 6% of the general adult population [5], and in up to 15% of patients in the primary care setting [6]. Although recognition of axSpA is improving, a mean delay of 4.9 years from onset of symptoms to diagnosis was recently reported, highlighting the challenge of establishing this diagnosis early in the disease course [7].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Imaging plays a critical role in the diagnosis of axSpA. Historically, imaging diagnosis was based on radiographs using the modified New York criteria [15]; however, the radiographic changes of axSpA were subsequently found to evolve slowly over the course of years [16,17]. Additionally, some patients with symptomatic AS did not have radiographic evidence of axSpA [18], driving the search for additional imaging biomarkers of early disease. As evolving literature accumulated on the utility of MRI in axSpA, the Assessment of SpondyloArthritis international Society (ASAS) established diagnostic criteria in 2009 for axSpA that included MRI in the diagnostic algorithm, promoting the diagnosis of both patients with radiographically evident axSpA (radiographic-axSpA or classic AS) as well as patients with negative radiographs who may have inflammatory changes demonstrated on MRI (nonradiographic-axSpA) [17,19]. It was later shown that a portion of patients with nonradiographic-axSpA will


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Reprint requests to: publications@acr.org


Inflammatory Back Pain

Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Inflammatory Back Pain


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. progress to radiographic-axSpA over the course of years [20], although it is uncertain if radiographic-axSpA and nonradiographic-axSpA represent a continuum of the same entity or if they are truly separate disease subsets. This is the topic of some debate [1,21-23]. The development of the ASAS criteria facilitated diagnosis of patients at an earlier stage of disease and allowed more patients with axSpA to be considered for biologic therapy [17,19,22]. However, care should be taken to acknowledge that the ASAS criteria are designed for use in clinical research, not for definitive clinical diagnosis.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Beyond the important roles of imaging in early diagnosis and treatment in axSpA patients, those with advanced axSpA resulting in ankylosis are a subset of patients that warrants further discussion. These patients, classically considered to have AS, develop spinal rigidity combined with osteoporosis resulting in a risk of fracture even with low energy trauma or no apparent trauma [1,31-33]. These fractures are often unstable and involve all 3 spinal columns [31,34]. The cervical spine is most frequently involved [32,33,35]. Associated neurologic deficits have been reported in 21% to 100% of patients, and other complications reported in 84% of patients [32]. The diagnosis can be delayed in 15% to 41% of cases, and therefore, clinical suspicion for fracture must be elevated in the appropriate setting given the severity of these injuries. Many patients undergo surgical fixation of these injuries, although unfavorable outcomes with relatively high morbidity and mortality are reported [32,35]. Early use of advanced imaging modalities is crucial in these patients to facilitate a timely diagnosis.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. OR Discussion of Procedures by Variant Variant 1: Inflammatory back pain. Suspected axial spondyloarthritis. Initial imaging. The body regions covered in this clinical scenario are the sacroiliac joints, cervical, thoracic, and lumbar spine. These body regions might be evaluated separately or in combination as guided by physical examination findings, patient history, and other available information.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Bone Scan with SPECT or SPECT/CT Sacroiliac Joints Bone scintigraphy with single-photon emission computed tomography (SPECT) or SPECT/CT is not routinely obtained as the initial imaging modality in the evaluation of suspected axSpA, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Bone Scan with SPECT or SPECT/CT Spine Area of Interest Bone scintigraphy with SPECT or SPECT/CT is not routinely obtained as the initial imaging modality in the evaluation of suspected axSpA, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. CT Sacroiliac Joints CT is not routinely obtained as the initial imaging modality in the evaluation of suspected axSpA, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. CT Spine Area of Interest CT is not routinely obtained as the initial imaging modality in the evaluation of suspected axSpA, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Fluoride PET/CT Skull Base to Mid-Thigh F-18-fluoride PET/CT is not routinely obtained as the initial imaging modality in the evaluation of suspected axSpA, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. MRI Sacroiliac Joints MRI is not routinely obtained as the initial imaging modality in the evaluation of suspected axSpA; however, it is known that the inflammatory changes of sacroiliitis on MRI can precede radiographic structural findings of sacroiliitis by three to seven years [36,37], resulting in a low sensitivity of radiographs for detection of early disease [16,17]. In cases of those with a short duration of symptoms, MRI of the sacroiliac joints could be considered as the initial imaging modality [22].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. MRI Spine Area of Interest MRI is not routinely obtained as the initial imaging modality in the evaluation of suspected axSpA, and there is no relevant literature supporting MRI of the spine in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. US Sacroiliac Joints Ultrasound (US) is not routinely obtained as the initial imaging modality in the evaluation of suspected axSpA, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. US Spine Area of Interest US is not routinely obtained as the initial imaging modality in the evaluation of suspected axSpA, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Variant 2: Inflammatory back pain. Suspected axial spondyloarthritis. Additional imaging following radiographs. Next imaging study. The body regions covered in this clinical scenario are the sacroiliac joints, cervical, thoracic, and lumbar spine. These body regions might be evaluated separately or in combination as guided by physical examination findings, patient history, and other available information.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Bone Scan with SPECT or SPECT/CT Sacroiliac Joints Bone scintigraphy is not routinely suggested in the evaluation of patients with suspected axSpA [22]. Conventional bone scintigraphy has low to moderate sensitivity and variable specificity for the diagnosis of axSpA [41,42,50]. If bone scintigraphy is used, SPECT should be performed during the examination because of the complexity of the sacroiliac joint anatomy [51]. Although bone scintigraphy is not typically performed during the evaluation of suspected axSpA because of its limited diagnostic utility, there is recent data that hybrid SPECT/CT has higher sensitivity than conventional bone scintigraphy in the detection of sacroiliitis [52,53]. However, there is not enough evidence currently to support its routine use for evaluation of the sacroiliac joints and spine.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Bone Scan with SPECT or SPECT/CT Sacroiliac Joints and Spine Area of Interest Bone scintigraphy is not routinely suggested in the evaluation of patients with suspected axSpA [22]. Conventional bone scintigraphy has low to moderate sensitivity and variable specificity for the diagnosis of axSpA [41,42,50]. If bone scintigraphy is used, because of the complexity of the sacroiliac joint anatomy, the use of SPECT should be performed during the examination [51]. Although bone scintigraphy is not typically performed during the evaluation of suspected axSpA because of its limited diagnostic utility, there is recent data that hybrid SPECT/CT has higher sensitivity than conventional bone scintigraphy in the detection of sacroiliitis [52,53]. However, there is not enough evidence currently to support its routine use for evaluation of the sacroiliac joints and spine.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. CT Sacroiliac Joints CT demonstrates the structural changes of sacroiliitis in patients with axSpA that may not be apparent on radiographs [22]. These structural changes, including erosions, sclerosis, bone formation, and ankylosis, are best demonstrated on sacroiliac protocol examinations that include obliquely oriented reformatted images prescribed parallel and perpendicular to the long axis of the sacrum [54]. Several studies have shown CT to have higher sensitivity for detection of sacroiliitis than radiography [43,44,47,55]. Low-dose CT is increasingly being performed and can demonstrate the fine structural changes of axSpA better than radiography [45]. Additionally, the interreader reliability has shown to be excellent for grading sacroiliitis on CT, higher than for radiography, because of the increased level of structural detail demonstrated by CT [47]. Although conventional CT has the ability to demonstrate the chronic structural changes of sacroiliitis, it cannot demonstrate active inflammation, and therefore MRI remains the technique of choice for the diagnosis of axSpA [1,3,19,22]. There is evolving literature on the use of dual-energy CT (DECT) in the evaluation of sacroiliitis in axSpA, with early studies showing the ability of DECT to demonstrate bone marrow edema in patients with axSpA in addition to the inherent ability of CT to demonstrate the chronic structural changes of sacroiliitis [56,57]. One study shows that DECT has a sensitivity of 87% to 93% and specificity of 91% to 94% for detection of bone marrow edema using MRI as the reference standard, but more data are needed to support the diagnostic utility of DECT in the evaluation of axSpA [56].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. There is no role for intravenous (IV) contrast in CT evaluation of axSpA.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. CT Sacroiliac Joints and Spine Area of Interest CT demonstrates structural changes in the sacroiliac joints and spine in patients with axSpA that may not be apparent on radiographs [22]. These structural changes include erosions, sclerosis, bone formation, syndesmophytes, and ankylosis [49,54]. In addition to its diagnostic utility in assessment of the sacroiliac joints, CT of the spine has the ability to demonstrate syndesmophytes with higher sensitivity than radiographs, and low-dose protocols can be utilized [58]. CT is especially helpful for evaluation of the thoracic spine and facet joints, which can be challenging to evaluate on radiography [49]. There is not a consistently established convention to guide the clinician on whether to image only the sacroiliac joints or both the sacroiliac joints and spine in patients with suspected axSpA. However, spinal involvement is common, and numerous studies have shown that axSpA involvement can be isolated to the spine, isolated to the sacroiliac joints, or can involve both the sacroiliac joints and spine [19,59-63]. Therefore, if CT is performed, imaging the spine in addition to the sacroiliac joints is beneficial in the setting of symptoms referable to the spine.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. There is no role for IV contrast in the CT evaluation of axSpA.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Fluoride PET/CT Skull Base to Mid-Thigh There is not enough data to support the routine use of F-18-fluoride PET/CT in the evaluation of patients with suspected axSpA. F-18-fluoride has been shown to be a potentially useful tracer in identifying sites of osteoblastic activity in axSpA patients [64], with uptake corresponding to sites of active bone formation on histology [65]. Uptake on PET/CT has also been shown to correlate with clinical disease activity in patients with axSpA [66,67]; however, there is conflicting evidence regarding the extent to which tracer uptake correlates with specific


Inflammatory Back Pain

Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Inflammatory Back Pain


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. inflammatory and structural lesions seen on CT and MRI resulting in uncertainty about its diagnostic utility [64,67- 72]. In one study, the interreader reliability of diagnosing sacroiliitis on PET/CT was poor and substantially lower than that for MRI or CT [67]. In a small study using radiographs as the reference standard, F-18-fluoride PET/CT had a sensitivity of 80% and specificity of 77% for the detection of sacroiliitis in AS, although there are inherent limitations in the use of radiographs as the reference standard for diagnosing axSpA [73]. Given the available data, the utility of PET/CT in the diagnosis of axSpA is uncertain at this time.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. MRI Sacroiliac Joints After radiography is performed, MRI of the sacroiliac joints is the next imaging technique of choice in the evaluation of patients with suspected axSpA [1,3,19,22]. MRI of the sacroiliac joints is widely recognized as an important tool in the evaluation of patients with suspected axSpA, resulting in improved diagnostic confidence and yielding findings that stimulate changes in both diagnosis and treatment plans for patients [1,3,19,22,74]. Additionally, MRI findings have been shown to be predictive of both subsequent radiographic disease progression and the likelihood of response to therapy [36,63,75,76].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. MRI, utilizing short tau inversion recovery (STIR) and T1-weighted images, can identify both active inflammatory lesions of the sacroiliac joints (bone marrow edema, capsulitis, synovitis, and enthesitis) and chronic structural lesions (sclerosis, erosions, fat deposition, and ankylosis) that are typical for sacroiliitis [38,77]. MRI demonstrates active sacroiliitis with higher sensitivity and earlier than radiography because of its ability to detect inflammatory lesions of axSpA [13,36,37,78]. The inflammatory changes of sacroiliitis on MRI have been shown to precede structural radiographic findings by three to seven years [36,37]. MRI can also detect the chronic structural lesions of the sacroiliac joints with higher accuracy than radiographs [45].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. It is important to recognize that the sensitivity and specificity of MRI for axSpA depends on the imaging criteria used, patient population, and reference standard for diagnosis. Early literature showed 95% sensitivity and 100% specificity of MRI for sacroiliitis, substantially higher than radiographs or bone scintigraphy, although that study included a small number of patients, and most subsequent studies demonstrate smaller yields [41]. The ASAS criteria developed in 2009 utilize the presence of bone marrow edema to define a positive MRI of the sacroiliac joints in axSpA [79]. Using solely the imaging arm of the ASAS algorithm (which includes positive radiographs or positive MRI with one clinical axSpA feature), the ASAS criteria were initially shown to have a sensitivity of 66.2% and specificity of 97.3%, although by combining both imaging and clinical arms of the algorithm the sensitivity was 82.9% and specificity was 84.4% for axSpA [19]. Subsequently, in an inception cohort followed for 8 years, the ASAS definition of a positive MRI demonstrated a sensitivity of 79% and a specificity of 89% for the diagnosis of axSpA [80]. Although the presence of bone marrow edema provides a sensitive evaluation for inflammatory changes in axSpA, bone marrow edema can also be seen in noninflammatory conditions such as in age-related degenerative changes, postpartum patients, patients with chronic back pain, athletes, and in up to 30% of healthy controls [81-85]. As a result, the ASAS MRI criteria have been criticized for decreased specificity of bone marrow edema as the sole MRI diagnostic criterion [82]. Importantly, although bone marrow edema may be nonspecific in some cases, one study found that the presence of a deep bone marrow edema lesion which extends at least 1 cm deep to the articular surface is more specific and found almost exclusively in axSpA [86]. Structural changes of axSpA including erosions, sclerosis, fatty deposition, and ankylosis are not accounted for in the ASAS definition of a positive MRI, although they are important findings in axSpA and should be identified in clinical practice [38]. Two related studies on a group of 187 patients demonstrated high sensitivity of 90% to 92% and specificity of 94% to 97% for the diagnosis of AS by using global assessment of both inflammatory and structural lesions [83,87], and subsequently this group of authors showed that identifying erosions and/or bone marrow edema increases sensitivity for axSpA compared with bone marrow edema alone, without decreasing specificity [85]. They also showed that identifying erosions and/or bone marrow edema on MRI increased both sensitivity and specificity for axSpA compared with the diagnostic criterion of solely bone marrow edema [88]. Subchondral fatty deposition, another chronic finding of structural marrow remodeling, is an additional helpful and highly specific finding in axSpA with reported specificities up to 95% to 98% [89,90]. Finally, intra-articular signal changes including increased T1 signal, T2 hyperintense joint fluid, and ankylosis are highly specific findings for axSpA, and when found together with bone marrow edema can increase the positive predictive value for a diagnosis of axSpA compared with bone marrow edema alone [91,92]. Overall, it is clear that interrogation of sacroiliac joint MRI using both STIR and T1-weighted images is critical to identify both the inflammatory and structural changes of axSpA in clinical practice.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. MRI has long been considered inferior to CT in demonstrating the structural changes of axSpA, although evolving literature demonstrates that a specific MRI sequence, volumetric interpolated breath-hold examination (VIBE), can


Inflammatory Back Pain


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. demonstrate erosions with higher sensitivity and similar specificity compared to conventional T1-weighted imaging, and may be comparable to CT [93,94], making it a promising technique for identifying structural lesions of axSpA on MRI.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Multiple studies have examined diffusion-weighted imaging and dynamic contrast-enhanced MRI to determine their diagnostic utility and performance as imaging biomarkers of inflammation. Although these studies show correlation between diffusion-weighted imaging, dynamic contrast-enhanced, and conventional sequences, there is no evidence that these MRI techniques provide additional diagnostic utility compared with conventional MRI sequences [95- 106].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Contrast-enhanced MRI can demonstrate active inflammatory changes of the sacroiliac joints in axSpA, although multiple studies show that noncontrast and contrast-enhanced MRI have overall similar diagnostic utility for axSpA [107-111]. Contrast-enhanced MRI has been reported to increase the diagnostic confidence of MRI interpretation in 1 study [107].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. MRI Sacroiliac Joints and Spine Area of Interest After radiography is performed, MRI is the next imaging technique of choice in the evaluation of suspected axSpA [1,3,19,22]. MRI of the sacroiliac joints and spine is associated with improved diagnostic confidence in axSpA and yields findings that stimulate changes in both diagnosis and treatment plans for patients [74]. Although there is agreement in the literature and among experts that MRI should include the sacroiliac joints, there is not a consistently established convention to guide the clinician on whether to image only the sacroiliac joints or both the sacroiliac joints and the spine in patients with suspected axSpA [1,3,19,22]. Not unexpectedly, there is heterogeneity in clinical practice regarding the use of MRI to evaluate the sacroiliac joints and/or spine in these patients [112]. One study has shown that the majority of patients can be diagnosed with axSpA by obtaining MRI of the sacroiliac joints only [60]. Another study shows that the addition of spine MRI to sacroiliac joint MRI adds little incremental value in the diagnosis of nonradiographic axSpA [113]. However, axSpA often involves the axial skeleton proximal to the sacroiliac joints and may exhibit findings isolated to the spine. For example, in a study of whole-body MRI in active axSpA, 99% of patients were found to have active inflammatory lesions in the axial skeleton, with inflammatory changes isolated to the sacroiliac joints in 52% of patients, inflammatory changes isolated to the spine in 5% of patients, and with inflammatory changes at both the sacroiliac joints and spine in 41% of patients [59]. Other studies have shown widely varying degrees of isolated spinal involvement on MRI ranging from 1% to 49% [19,60-63,114,115]. In early axSpA, it has been shown that inflammation involving both the sacroiliac joints and spine can be seen in 28.3% of patients [116]. Therefore, it can be useful in some cases to image both the sacroiliac joints and the spine to help ensure MRI yields the highest diagnostic utility and establishes the extent of disease burden. The decision on whether to image the spine as well as the sacroiliac joints could be based on the site of symptoms. Although there is some disagreement about the extent to which inflammatory changes in the axial skeleton correspond with symptoms, imaging the spine in the clinical region of interest is beneficial in the setting of referable symptoms [62,117-119]. Multiple authors utilize whole-spine or whole-body MRI to identify the burden of disease throughout the spine rather than imaging specific segments because findings may potentially be found in any portion of the spine [10,59,63,89,114,120-122].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. The spine MRI findings of axSpA include the active inflammatory changes of spondylitis and spondylodiscitis, inflammatory changes of the costovertebral joints, costotransverse joints, and facet joints, and areas of enthesitis along other vertebral ligamentous attachments [123]. The chronic structural changes of fatty deposition, erosions, and syndesmophytes are also characteristic findings [123]. One study showed that the presence of two or more corner inflammatory lesions had a sensitivity of 69% and specificity of 94% for AS and that lateral vertebral inflammatory lesions had high specificity of 97% [120]. The presence of multiple lesions in the spine has shown to be useful; specifically the presence of at least 5 inflammatory lesions or 5 fatty lesions in the spine has been shown to have a specificity of 95% for axSpA [89]. One study shows that the corner sign in the lumbar spine on T1- weighted or T2-weighted images without fat saturation has a sensitivity of 62% and specificity of 96% for AS [12]. Furthermore, it has been shown that the presence of multiple fatty corner lesions in the spine has a high specificity of 98% and can be useful in the absence of active inflammatory lesions [11]. The ASAS considers a spine MRI positive for axSpA if there are three or more sites of inflammatory spondylitis and considers fatty corner deposition at several sites suggestive of axSpA especially in younger adults [123]. A subsequent study confirmed that the presence of multiple corner lesions has high specificity for axSpA, although it showed a low diagnostic utility because of low sensitivity [121]. Importantly, the findings on spine MRI should be interpreted alongside sacroiliac joint MRI to ensure the highest diagnostic utility. Additionally, MRI findings should be interpreted with specific


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. attention to identify associated morphologic findings such as disc degeneration or osteophytes that favor degenerative changes rather than axSpA, because both inflammatory and fatty lesions can occur in degenerative changes [124].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Contrast-enhanced MRI can demonstrate active inflammatory changes of the sacroiliac joints and spine in axSpA, although multiple studies show that noncontrast and contrast-enhanced MRI have overall similar diagnostic utility for axSpA [9,107-111,125-129]. Contrast-enhanced MRI has been reported to increase the diagnostic confidence and reliability of MRI interpretation in 2 studies [9,107].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. US Sacroiliac Joints US is not suggested as a routine diagnostic modality for the evaluation of sacroiliitis in patients with suspected axSpA because of its lack of established diagnostic utility [22]. Importantly, US provides evaluation limited to the superficial posterior margins of the sacroiliac joints, and therefore many structural details are not demonstrated. Many of the available studies examine the utility of Doppler evaluation. It has been shown that patients with active sacroiliitis because of axSpA have lower Doppler US resistive indices than healthy controls or patients with osteoarthritis at the sacroiliac joints [130-132]. Using MRI as the reference standard in a study of 51 patients with AS, a pulsatile monophasic waveform was shown to have a sensitivity of 82% and specificity of 92% for active disease, although 18.5% of active AS patients, 70.8% of inactive AS patients, and 63.3% of normal patients had no Doppler flow identified, and the sensitivity for detection of AS patients overall was only 43% [133]. One study reported higher sensitivity of contrast-enhanced US compared with conventional US [134,135]. A recent systematic review of US of the sacroiliac joints in spondyloarthritis reported a median sensitivity of 90% and specificity of 89% in seven of those studies, although with variation in the method of evaluation and reference standard. The authors concluded that there is not enough evidence to support the use of US for the diagnosis of axSpA [136].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. US Sacroiliac Joints and Spine Area of Interest US is not suggested as a routine diagnostic modality for the evaluation of sacroiliitis in patients with suspected axSpA because of its lack of established diagnostic utility [22]. Importantly, US provides evaluation limited to the superficial posterior margins of the sacroiliac joints and spine, and therefore many structural details are not demonstrated. Many of the available studies examine the utility of Doppler evaluation. In addition to data showing decreased resistive indices at the sacroiliac joints in patients with active sacroiliitis joints [130-132], there is evidence that resistive indices of the thoracolumbar paraspinal areas are also decreased in patients with AS [132]. However, there is not enough evidence to support the use of US for the diagnosis of axSpA.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Variant 3: Inflammatory back pain. Suspected axial spondyloarthritis. Negative radiographs and negative MRI of the sacroiliac joints. Next imaging study. The body regions covered in this clinical scenario are the sacroiliac joints, cervical, thoracic, and lumbar spine. These body regions might be evaluated separately or in combination as guided by physical examination findings, patient history, and other available information.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Bone Scan with SPECT or SPECT/CT Spine Area of Interest Bone scintigraphy is not routinely suggested in the evaluation of patients with suspected axSpA because of its lack of established diagnostic utility [22]. Conventional bone scintigraphy has low to moderate sensitivity and variable specificity for the diagnosis of axSpA [41,42,50]. If bone scintigraphy is used, because of the complexity of the spine anatomy, the use of SPECT should be performed during the examination [51]. Although bone scintigraphy is not typically performed during the evaluation of suspected axSpA because of its limited diagnostic utility, there is recent data that hybrid SPECT/CT has higher sensitivity than conventional bone scintigraphy in the detection of sacroiliitis [52,53], although there is not enough evidence at this time to support its routine use for evaluating the sacroiliac joints or spine.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. CT Spine Area of Interest CT demonstrates structural changes in the spine that may not be apparent on radiographs [22], including structural changes such as erosions, sclerosis, bone formation, syndesmophytes, and ankyloses [49,54]. CT has been shown to demonstrate syndesmophytes with higher sensitivity than radiographs and low-dose protocols can be utilized [58]. CT is especially helpful for evaluation of the thoracic spine and facet joints, which can be challenging to evaluate on radiography [49]. Although MRI remains the technique of choice for the diagnosis of axSpA [1,3,19,22], CT can be useful in patients in the setting of prior negative radiographic and negative CT evaluation of


Inflammatory Back Pain

Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Inflammatory Back Pain


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. the sacroiliac joints in order to identify patients with axSpA who have disease isolated to the spine, which has been shown to occur in a variable percentage of patients based on data from MRI studies [19,59-63].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. There is no role for contrast-enhanced CT in the evaluation of axSpA.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Fluoride PET/CT Skull Base to Mid-Thigh There is not enough data to support the routine use of PET/CT in the evaluation of patients with suspected axSpA. F-18-fluoride has been shown to be a potentially useful tracer in identifying sites of osteoblastic activity in axSpA patients [64,65]. Uptake on PET/CT has also been shown to correlate with clinical disease activity in patients with axSpA [66,67]; however, there is conflicting evidence regarding the extent to which tracer uptake correlates with specific inflammatory and structural lesions seen on CT and MRI resulting in uncertainty about its diagnostic utility [64,67-72]. In one study, the interreader reliability of diagnosing sacroiliitis on PET/CT was poor and substantially lower than that for MRI or CT [67]. In a small study using radiographs as the reference standard, F-18-fluoride PET/CT had a sensitivity of 80% and specificity of 77% for the detection of sacroiliitis in AS, although there are inherent limitations in the use of radiographs as the reference standard for diagnosing axSpA [73]. Given the available data, the utility of PET/CT in the diagnosis of axSpA, including its utility in assessment of the spine, is uncertain at this time.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. MRI Spine Area of Interest Although MRI of the sacroiliac joints has high utility for the diagnosis of axSpA, some patients will not demonstrate imaging features of axSpA in the sacroiliac joints on MRI as indicated by sensitivities of all studies to varying degrees below 100% [22], and therefore some patients may need further imaging evaluation with MRI given that it is the imaging modality of choice for the diagnosis of axSpA [1,3,19,22]. Studies have shown widely varying degrees of isolated spinal involvement on MRI in axSpA ranging from 1% to 49% [19,59-63,114,115]. Therefore, imaging of the spine is beneficial for patients in whom there is suspicion for axSpA but imaging of the sacroiliac joints has been negative. Some authors have shown the utility of using whole-spine or whole-body MRI to identify the burden of disease rather than selecting specific areas of the spine to image because findings may be potentially isolated to any portion of the spine [10,59,63,89,114,120-122].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. The spine MRI findings of axSpA include the active inflammatory changes of spondylitis and spondylodiscitis, the inflammatory changes of the costovertebral joints, costotransverse joints, and facet joints and areas of enthesitis along other vertebral ligamentous attachments [123]. The chronic structural changes of fatty deposition, erosions, and syndesmophytes are also characteristic findings [123]. One study showed that the presence of two or more corner inflammatory lesions had a sensitivity of 69% and specificity of 94% for AS and that lateral vertebral inflammatory lesions had high specificity of 97% [120]. The presence of multiple lesions in the spine has shown to be useful; specifically the presence of at least five inflammatory lesions or five fatty lesions in the spine has been shown to have a specificity of 95% for axSpA [89]. One study shows that the corner sign in the lumbar spine on T1-weighted or T2-weighted images without fat saturation has a sensitivity of 62% and specificity of 96% for AS [12]. Furthermore, it has been shown that the presence of multiple fatty corner lesions in the spine has a high specificity of 98% and can be useful in the absence of active inflammatory lesions [11]. The ASAS considers a spine MRI positive for axSpA if there are three or more sites of inflammatory spondylitis and considers fatty corner deposition at several sites suggestive of axSpA especially in younger adults [123]. A subsequent study confirmed that the presence of multiple corner lesions has a high specificity for axSpA, although it showed a low diagnostic utility because of low sensitivity [121]. Importantly, the findings on spine MRI should be interpreted alongside sacroiliac joint MRI to ensure the highest diagnostic utility. Additionally, MRI findings should be interpreted with specific attention to identify associated morphologic findings such as disc degeneration or osteophytes that favor degenerative changes rather than axSpA, because both inflammatory and fatty lesions can occur in degenerative changes [124].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Contrast-enhanced MRI can demonstrate active inflammatory changes of the spine in axSpA, although multiple studies show that noncontrast and contrast-enhanced MRI have overall similar diagnostic utility for axSpA [9,125- 129]. Contrast-enhanced MRI has been reported to increase reliability of MRI interpretation in 1 study [9].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Radiography Spine Area of Interest If radiographs and MRI of the sacroiliac joints have been negative, radiographic evaluation of the spine can be obtained to evaluate for the structural imaging findings of axSpA, including syndesmophytes, erosions, shiny corners, vertebral body squaring, and ankylosis [38]. Although radiographs show structural changes, they will not demonstrate the inflammatory changes or fatty infiltration that can be demonstrated on MRI.


Inflammatory Back Pain


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. US Spine Area of Interest US is not beneficial as a diagnostic tool for the evaluation of sacroiliitis in patients with suspected axSpA because of its lack of established diagnostic utility [22]. Importantly, US provides limited evaluation of the superficial posterior margins of the spine, and therefore many structural details are not demonstrated. There is a paucity of evidence literature evaluating US in the spine in patients with axSpA. One study demonstrates that resistive indices of the thoracolumbar paraspinal areas are also decreased in patients with AS, similar to findings reported at the sacroiliac joints [132].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Variant 4: Known axial spondyloarthritis. Follow-up for treatment response or disease progression. The body regions covered in this clinical scenario are the sacroiliac joints, cervical, thoracic, and lumbar spine. These body regions might be evaluated separately or in combination as guided by physical examination findings, patient history, and other available information.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Bone Scan with SPECT or SPECT/CT Sacroiliac Joints Bone scintigraphy is not routinely obtained to evaluate for treatment response or disease progression in axSpA patients, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Bone Scan with SPECT or SPECT/CT Sacroiliac Joints and Spine Area of Interest Bone scintigraphy is not routinely obtained to evaluate for treatment response or disease progression in axSpA patients, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. CT Sacroiliac Joints CT demonstrates structural changes of the sacroiliac joints in axSpA that may not be apparent on radiographs [22]; however, it is not routinely used for follow-up or assessing disease progression.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. CT Sacroiliac Joints and Spine Area of Interest CT demonstrates structural changes of the sacroiliac joints in axSpA that may not be apparent on radiographs [22] and can better demonstrate spinal syndesmophyte growth than radiographs using low-dose techniques [49,58]. However, it is not routinely used for follow-up or assessing disease progression.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Fluoride PET/CT Skull Base to Mid-Thigh F-18-fluoride PET/CT is not routinely obtained to evaluate for treatment response or disease progression in axSpA patients, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. MRI Sacroiliac Joints There is no standard method of following patients with MRI to evaluate for treatment response or disease progression [22,30]. Although multiple studies demonstrate decreasing inflammation on MRI following treatment with TNF-inhibitors, including some long-term studies showing sustained reduction in inflammation, the degree to which MRI findings correlate with disease activity is variable [30]. The American College of Rheumatology and European League Against Rheumatism agree that the decision to repeat MRI to assess disease activity or monitor for disease response depends on the clinical circumstances [22,30]. Specifically, MRI of the sacroiliac joints may be helpful for cases in which the disease activity is unclear, available clinical or laboratory data are conflicting, or knowledge of MRI findings is expected to alter treatment [30]. MRI can also detect chronic structural changes on axSpA in the sacroiliac joints, although the clinical utility of follow-up for that purpose is not established [137]. Noncontrast and contrast-enhanced MRI have overall similar diagnostic utility for evaluation of the sacroiliac joints in axSpA [107-111]. The Spondyloarthritis Research Consortium of Canada method has been utilized as a scoring system for quantification and follow-up of lesions at the sacroiliac joints on MRI [138].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. MRI Sacroiliac Joints and Spine Area of Interest There is no standard method of following patients with MRI to evaluate for treatment response or disease progression [22,30]. Although multiple studies demonstrate decreasing inflammation on MRI following treatment with TNF-inhibitors, including some long-term studies showing sustained reduction in inflammation, the degree to which MRI findings correlate with disease activity is variable [30]. The American College of Rheumatology and European League Against Rheumatism agree that the decision to repeat MRI to assess disease activity or monitor for disease response depends on the clinical circumstances [22,30]. Specifically, MRI of the sacroiliac joints and spine may be helpful for cases in which the disease activity is unclear, available clinical or laboratory data are conflicting, or knowledge of MRI findings is expected to alter treatment [30]. MRI can also detect chronic structural changes on axSpA in the sacroiliac joints and spine, although the clinical utility of follow-up for that purpose is not


Inflammatory Back Pain

Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Inflammatory Back Pain


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. established [110,137]. Noncontrast and contrast-enhanced MRI have overall similar diagnostic utility for evaluation of the sacroiliac joints and spine in axSpA [9,107-111,125-129]. The Spondyloarthritis Research Consortium of Canada and Berlin methods have been used as scoring systems for quantification and follow-up of lesions in the sacroiliac joints and spine on MRI [138-140].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Radiography Sacroiliac Joints There is no standard method of following patients with radiographs to evaluate for progression of structural changes [22], and the American College of Rheumatology recommends against routine radiographic follow-up given the lack of proven benefit [30]. Repeat radiographs can be obtained as necessary for counseling patients on the status and prognosis of their disease, although radiographs are more typically performed to evaluate the spine rather than the sacroiliac joints [30]. This is because of the low utility of sacroiliac joint radiographs for detecting disease progression based on the relatively poor intra- and interreader reliability of interpretation [141]. Radiographs can demonstrate evolving structural changes or bone formation, although these changes occur slowly over time at the sacroiliac joints, often requiring years to detect a change and prompting many authors to suggest a radiographic imaging interval of axSpA patients of no less than 2 years for assessment of disease progression [141-146]. There is evidence that patients on TNF-inhibitors may have slower progression of structural damage at the sacroiliac joints [147,148], although there is some disagreement in the literature [149]. Radiographic scoring systems, such as the Bath Ankylosing Spondylitis Radiology Index for the sacroiliac joints, have been utilized for quantification and follow-up of radiographic progression in patients over time [29,150].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Radiography Sacroiliac Joints and Spine Area of Interest There is no standard method of following patients with radiographs to evaluate for progression of structural changes [22], and the American College of Rheumatology recommends against routine follow-up given the lack of proven benefit [30]. Repeat radiographs can be obtained for counseling patients on the status and prognosis of their disease, although radiographs are more typically performed to evaluate the spine rather than the sacroiliac joints [30]. This is because of the low utility of sacroiliac joint radiographs for detecting disease progression based on the relatively poor intra- and interreader reliability of interpretation [141]. Radiographic follow-up can demonstrate evolving structural changes or bone formation, although these changes occur slowly over time at the sacroiliac joints and spine, often requiring years to detect a change and prompting some authors to suggest a radiographic imaging interval of axSpA patients of no less than 2 years for assessment of disease progression [141,143-145,151-153]. There is evidence that patients on TNF-inhibitors may have slower progression of structural damage at the sacroiliac joints and spine [148,154-156], although there is some disagreement in the literature [149]. Radiographic scoring systems, such as the Bath Ankylosing Spondylitis Radiology Index for the sacroiliac joints and the modified Stoke Ankylosing Spondylitis Spine Score for the spine, have been utilized for quantification and follow-up of radiographic progression over time [29,150,157].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. US Sacroiliac Joints US of the sacroiliac joints is not utilized as a routine diagnostic tool in the assessment of treatment response or disease progression. Importantly, a US evaluation is limited to the superficial posterior margins of the sacroiliac joints and spine, and therefore many structural details are not demonstrated. Many of the available studies examine the utility of Doppler evaluation. There is evidence in small studies that Doppler resistive indices at the sacroiliac joints increase following treatment with TNF-inhibitors [132,158,159], although more data are necessary to justify the routine use of US in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. US Sacroiliac Joints and Spine Area of Interest US of the sacroiliac joints is not utilized as a routine diagnostic tool in the assessment of treatment response or disease progression. Importantly, an US evaluation is limited to the superficial posterior margins of the sacroiliac joints and spine, and therefore many structural details are not demonstrated. Many of the available studies examine the utility of Doppler evaluation. There is evidence in small studies that Doppler-resistive indices at the sacroiliac joints increase following treatment with TNF-inhibitors [132,158,159], and there is limited data showing potentially similar findings in thoracolumbar paraspinal spondylitis [132], although more data are necessary to justify routine use of US in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Variant 5: Axial spondyloarthritis with spine ankylosis. Suspected fracture. Initial imaging. The body regions covered in this clinical scenario are the cervical, thoracic, and lumbar spine. These body regions might be evaluated separately or in combination as guided by physical examination findings, patient history, and other available information.


Inflammatory Back Pain


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Bone Scan with SPECT or SPECT/CT Spine Area of Interest Bone scintigraphy is not routinely obtained to evaluate for suspected fracture in axSpA patients with spine ankylosis, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. CT Spine Area of Interest CT and MRI are the imaging techniques of choice for definitive evaluation of the patient with ankylosis and suspected fracture [22,32]. CT can be performed rapidly in trauma patients and excellently depicts the complex structures of each vertebral column that can injured in this setting [31] and therefore is typically the preferred modality [22]. The sensitivities of CT and MRI for fracture detection are similar in the available small case series, notably with some fractures better detected on CT and some better detected on MRI, suggesting these modalities have a degree of complementary diagnostic utility [34,160,161]. CT, similar to MRI, has higher sensitivity for detection of fracture in the setting of ankylosis than radiographs [31,32,34,161]. The cervical spine is most frequently involved in a fracture [32,33,35]. The presence of two or more fractures is common [160], and therefore, the entire spine should be imaged to both ensure detection of the potential fracture(s) and to detect multilevel involvement [32].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Fluoride PET/CT Skull Base to Mid-Thigh F-18-fluoride PET/CT is not routinely obtained to evaluate for suspected fracture in axSpA patients with spine ankylosis, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. MRI Spine Area of Interest CT and MRI are the imaging techniques of choice for definitive evaluation of the patient with ankylosis and suspected fracture [22,32]. Technical difficulties can be encountered during an MRI of some patients with spine ankylosis in the acute posttraumatic setting, including inability of patients to remain immobile during the examination, difficulty with coil selection, and motion artifact. These factors combined with varying degrees of spinal deformity and occasional lack of associated bone marrow edema at fracture sites can result in challenging interpretation [160]. Therefore, CT is typically the preferred modality in this setting [22]. The sensitivities of CT and MRI for fracture detection are similar in the available small case series, notably with some fractures better detected on CT and some better detected on MRI, suggesting these modalities have a degree of complementary diagnostic utility [34,160,161]. MRI, similar to CT, has higher sensitivity for detection of fracture in the setting of ankylosis than radiographs [32,34,161]. MRI can detect both osseous fractures as well as soft tissue injuries such as ligamentous disruption or spinal cord injury [31,34,160]. In the setting of neurologic deficit, MRI should be performed, either as the sole cross-sectional imaging modality or in addition to CT [22,162]. The cervical spine is most frequently involved by fracture [32,33,35]. The presence of two or more fractures is common [160], and therefore the entire spine should be imaged to both ensure detection of the potential fracture(s) and to detect multilevel involvement [32].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Radiography Spine Area of Interest Radiography of the spine can be considered as an initial imaging modality in patients with axSpA and suspected fracture [22], although fractures can be difficult to detect on radiographs in axSpA patients, especially in the setting of structural abnormalities and osteopenia, contributing further to an already inherent lower sensitivity of radiography for fracture detection compared with CT or MRI [31,32,34,160,161]. Negative radiographs in these patients should be followed by cross-sectional imaging. If obtained, radiographs should cover the entire spine in patients with ankylosis and suspected fracture because of the potential for multilevel fractures [32,160].


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Additionally, it is possible that the presence or extent of ankylosis in trauma patients, who may have diagnosed or undiagnosed axSpA, may not be established at the time of presentation following trauma and therefore initial radiographs may be crucial to identify this group of patients at risk for severe traumatic spinal injuries.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. US Spine Area of Interest US is not routinely obtained to evaluate for suspected fracture in axSpA patients with spine ankylosis, and there is no relevant literature supporting its use in this setting.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. 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.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Appropriateness Category Names and Definitions Relative Radiation Level Information Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level (RRL) indication has been included for each imaging


Inflammatory Back Pain

Inflammatory Back Pain Known or Suspected Axial Spondyloarthropathy PCAs. Inflammatory Back Pain


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Introduction/Background Antenatal hydronephrosis is the most frequent urinary tract anomaly detected on prenatal screening by ultrasonography (US). Antenatal hydronephrosis occurs approximately twice as often in males as in females [1-4]. With an estimated 4 million births per year in the United States, up to 80,000 fetal studies may detect antenatal hydronephrosis. Most antenatal hydronephrosis is transient with little long-term significance [5-8]. Few children with antenatal hydronephrosis, including some with ureteropelvic junction obstruction (UPJO), vesicoureteral reflux (VUR), and primary megaureter will have significant obstruction, develop symptoms or complications, which requires surgical intervention. Some male children will be diagnosed with more serious conditions, such as posterior urethral valves (PUV), which may require intervention. Early detection and treatment of obstructive uropathy is necessary to mitigate the potential morbidity from loss of renal function.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. During prenatal evaluation, most antenatal hydronephrosis is mild, and the cause cannot always be determined with certainty. As a result, postnatal evaluation of these children is frequently performed. In an effort to standardize grading of antenatal hydronephrosis, the Society for Fetal Urology (SFU) introduced a five point grading system in 1988, based on degree of pelvic and calyceal dilation and the thickness of the parenchyma overlying the calices [9]. Since its introduction, the SFU grading system has become the most widely used method to grade pediatric hydronephrosis [10]. Subsequently, several alternative classification schemes have also been devised [3,4,11,12]. Adherence to standardized reporting models is not well adopted according to a recent survey of pediatric radiologists [13,14], In order to increase standardization of reporting and care, a consensus group from many separate organizations recommended adoption of the urinary tract dilation (UTD) classification system which incorporates prenatal and postnatal imaging findings based on: 1) anterior-posterior renal pelvic diameter (APRPD); 2) calyceal dilation with distinction between central and peripheral calyceal dilation postnatally; 3) renal parenchymal thickness; 4) renal parenchymal appearance; 5) bladder abnormalities; and 6) ureteral abnormalities. For antenatal studies, the seventh US finding to report is the quantity of amniotic fluid [3]. This recently proposed grading classification system, as with any system, will require extensive evaluation to assess and confirm its usefulness in predicting clinical outcomes [3].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. For the purposes of the current evaluation, degree of hydronephrosis is based on the SFU grading. The SFU system has been in use for a longer period of time and has good inter-rater reliability [3,15,16]. There are studies that have shown increased accuracy of hydronephrosis grading system if APRPD is measured [17,18]. We therefore have included an APRPD of >15 mm on postnatal imaging as a sign of severe hydronephrosis. Over time, the UTD classification system may predominate, but at present, familiarity with the SFU system is more widespread. Inclusion of the APRPD >15 mm conforms to the intermediate- to high-risk urinary tract dilation stratification [3].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through society representation on expert panels. Participation by representatives from collaborating societies on the expert panel does not necessarily imply individual or society endorsement of the final document.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Reprint requests to: publications@acr.org


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. OR Discussion of Procedures by Variant Variant 1: Antenatal diagnosis of hydronephrosis. Initial neonatal imaging. US Kidneys and Bladder Retroperitoneal US in the immediate postnatal period evaluates for the presence and severity of underlying urologic abnormalities and therefore has a role in guiding management [3,6,12,19-25]. Because of the relative low urine production in newborns, initial imaging should be delayed at least 48 to 72 hours after birth [3,26-29]. Exceptions include newborns with severe, bilateral hydronephrosis and bladder abnormalities, oligohydramnios, or situations in which follow-up studies may be difficult to obtain. In these infants, earlier imaging is indicated [20,27,29,30].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Fluoroscopic Voiding Cystourethrography There is controversy regarding whether all children with antenatal hydronephrosis should undergo voiding cystourethrography (VCUG). A meta-analysis by the American Urology Association found that, on average, approximately 16% of neonates and infants with antenatal hydronephrosis will have VUR. The incidence of VUR was independent of degree of antenatal hydronephrosis, and a quarter of these were found to have no hydronephrosis on postnatal US [31]. There is disagreement over whether this VUR is clinically significant and therefore over the need for diagnosis. Some authors advocate VCUG for all infants with antenatal hydronephrosis, to guide treatment with prophylactic antibiotics [20,27,32,33]. However, currently, most authors (including the 2010 SFU consensus statement) recommend against routine VCUG for antenatal hydronephrosis [2,12,29,34,35]. This is largely because the benefit of prophylactic antibiotics in children with urinary tract infection (UTI) has not been clearly demonstrated and remains controversial. Some studies have suggested that prophylactic antibiotics may be beneficial in patients with VUR [36-38]. The efficacy of prophylactic antibiotics in preventing UTIs or renal damage in patients with antenatal hydronephrosis, with or without VUR, is difficult to determine because of variability in methods and results [39]. In addition, most of the VUR spontaneously resolves [40]. One of the potential risks of VCUG is iatrogenic UTI. This was reported in about 2% of VCUG studies performed for evaluation of antenatal hydronephrosis [39].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Voiding Urosonography Multiple recent investigations evaluating real-time contrast-enhanced US techniques have demonstrated a high degree of diagnostic accuracy, and some demonstrated increased sensitivity as compared to fluoroscopic VCUG in the detection of VUR [41-45]. The main potential disadvantage of voiding urosonography is a lower anatomical detail of the bladder and urethra, and therefore it should not be used as the first study for male patients. Therefore, arguments for and against using voiding urosonography are similar to that of VCUG with the exception of male patients.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Nuclear Medicine Cystography Some studies have suggested equal sensitivity for Tc-99m pertechnetate radionuclide cystography and VCUG [46], whereas others have indicated that radionuclide cystography has improved sensitivity for VUR in infants up to 1 year of age [47]. The main disadvantage of radionuclide cystography is that it does not provide anatomical details of the bladder and urethra and therefore should not be used as the first study for male patients. Therefore, arguments for and against using radionuclide cystography are similar to that of VCUG with the exception of male patients.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. DTPA Renal Scan There is no relevant literature to support the routine use of Tc-99m diethylenetriamine pentaacetic acid (DTPA) renal scan in the initial postnatal evaluation of antenatal hydronephrosis.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MAG3 Renal Scan There is no relevant literature to support the routine use of Tc-99m mercaptoacetyltriglycine (MAG3) diuretic renal scan in the initial postnatal evaluation of antenatal hydronephrosis.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MRI Abdomen and Pelvis There is no relevant literature to support the routine use of MR urography (MRU) in the initial postnatal evaluation of antenatal hydronephrosis.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Fluoroscopic Voiding Cystourethrography There is controversy regarding whether all children with antenatal hydronephrosis should undergo VCUG. A meta- analysis by the American Urology Association found that on average, approximately 16% of neonates and infants with antenatal hydronephrosis will have VUR. The incidence of VUR was independent of degree of antenatal hydronephrosis, and a quarter of these were found to have no hydronephrosis on postnatal US [31]. There is disagreement over whether this VUR is clinically significant and therefore over the need for diagnosis. Some authors advocate VCUG for all infants with antenatal hydronephrosis, to guide treatment with prophylactic antibiotics [20,27,32,33]. However, currently, most authors (including the 2010 SFU consensus statement) recommend against routine VCUG for antenatal hydronephrosis [2,12,29,34,35]. This is largely because the benefit of prophylactic antibiotic in children with UTI has not been clearly demonstrated [36]. The efficacy of prophylactic antibiotics in preventing UTIs or renal damage in patients with antenatal hydronephrosis, with or without VUR, is difficult to determine because of variability in methods and results [39]. In addition, most of the VUR spontaneously resolves [40]. One of the potential risks of VCUG is iatrogenic UTI. This was reported in about 2% of VCUG studies performed for evaluation of antenatal hydronephrosis [39].


Antenatal Hydronephrosis Infant


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. DTPA Renal Scan There is no relevant literature to support the routine use of Tc-99m DTPA renal scan in the setting of a normal neonatal US.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MAG3 Renal Scan There is no relevant literature to support the routine use of Tc-99m MAG3 diuretic renal scan in the setting of a normal neonatal US.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MRI Abdomen and Pelvis There is no relevant literature to support the routine use of MRU in the in the setting of a normal neonatal US.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Fluoroscopic Voiding Cystourethrography There is controversy regarding whether all children with antenatal hydronephrosis should undergo VCUG. A meta- analysis by the American Urology Association found that, on average, approximately 16% of neonates and infants with antenatal hydronephrosis will have VUR. The incidence of VUR was independent of degree of antenatal hydronephrosis, and a quarter of these were found to have no hydronephrosis on postnatal US [31]. There is disagreement over whether this VUR is clinically significant and therefore over the need for diagnosis. Some authors advocate VCUG for all infants with antenatal hydronephrosis, to guide treatment with prophylactic antibiotics [20,27,32,33]. However, currently, most authors (including the 2010 SFU consensus statement) recommend against routine VCUG for antenatal hydronephrosis [2,12,29,34,35]. This is largely because the benefit of prophylactic antibiotic in children with UTI has not been clearly demonstrated [36]. The efficacy of prophylactic antibiotics in preventing UTIs or renal damage in patients with antenatal hydronephrosis, with or without VUR, is difficult to determine because of variability in methods and results [39]. In addition, most of the VUR spontaneously resolves [40]. One of the potential risks of VCUG is iatrogenic UTI. This was reported in about 2% of VCUG studies performed for evaluation of antenatal hydronephrosis [39].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. DTPA Renal Scan There is no relevant literature to support the routine use of Tc-99m DTPA renal scan as the first imaging in the evaluation of mild antenatal hydronephrosis, because there is low risk of underlying anatomic abnormality such as UPJO in the setting of mild hydronephrosis.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MAG3 Renal Scan There is no relevant literature to support the routine use of Tc-99m MAG3 diuretic renal scan as the first imaging in the evaluation of mild antenatal hydronephrosis, because there is low risk of underlying anatomic abnormality such as UPJO in the setting of mild hydronephrosis.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MRI abdomen and pelvis There is no relevant literature to support the routine use of MRU in the initial evaluation of mild antenatal hydronephrosis.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. VUR can be either primary or secondary to other urologic abnormalities. In male patients with moderate or severe hydronephrosis found on neonatal US, VCUG has a role in the evaluation of urologic abnormalities that may need immediate care, and bladder outlet obstruction from PUV must be excluded [12,20,28,29,50,57]. The catheter placed for initial bladder decompression can be used for this study. There is no need to remove the bladder catheter to assess for PUV [58]. Frequently, the study will show VUR in addition to bladder wall thickening and the dilated posterior urethra. When the diagnosis of PUV is made, immediate referral to urology is needed. Furthermore, it can reveal other anomalies such as a duplex collecting system, which helps to determine whether the reflux is primary or secondary.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Other infants with severe or bilateral moderate antenatal hydronephrosis may have VUR in isolation. There is higher risk for UTI in children with VUR [59]. Although the benefit of prophylactic antibiotics in this population is unknown, some authors recommend beginning antibiotics on these patients [26,60].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Voiding Urosonography Multiple recent investigations evaluating real-time contrast-enhanced US techniques have demonstrated a high degree of diagnostic accuracy, and some demonstrated increased sensitivity compared to fluoroscopic VCUG in the detection of VUR [41-45]. However, given the significant disadvantage of voiding urosonography in providing lower anatomical detail of the bladder and urethra, it should not be used as the first study for male patients.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Nuclear Medicine Cystography Although some studies have suggested equal sensitivity for Tc-99m pertechnetate radionuclide cystography and VCUG [46], it does not provide sufficient anatomical detail of the bladder and urethra and therefore should not be used as the first study for male patients.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. DTPA Renal Scan Tc-99m DTPA is excreted primarily by glomerular filtration. Its extraction fraction is approximately 20% accounting for greater background, versus renal, activity compared to MAG3 [61]. Tc-99m DTPA renal scan provides information on renal function and urinary tract drainage based on split renal function and renal washout curves and can be useful for the evaluation of severe grade 3 and 4 hydronephrosis in concert with VCUG [20,29,53,62,63]. Given the lower glomerular filtration rate in newborns, these examinations are frequently delayed until at least 2 months of age [29,63-65]. However, because of its rapid renal clearance and primary excretion by the tubules on which furosemide acts, Tc-99m MAG3 is preferred over Tc-99m DTPA in patients with suspected obstruction or impaired renal function [61].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MAG3 Renal Scan Tc-99m MAG3 is primarily excreted through active renal tubular transport, and its extraction fraction is 40% to 50% [61]. This greater extraction fraction, versus DTPA, accounts for less background, versus renal, activity compared to DTPA. Because of its rapid renal clearance and primary excretion by the tubules on which furosemide acts, Tc-99m MAG3 is preferred over Tc-99m DTPA in patients with suspected obstruction or impaired renal function [61]. Tc-99m MAG3 renal scan is useful for the evaluation of severe grade 3 and 4 hydronephrosis and may be performed in concert with a VCUG study [20,29,53,62,63]. Tc-99m MAG3 renal scan provides information on renal function and urinary tract drainage based on split renal function [61].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Diuretic renal scan is used for diagnosis of multiple causes of obstruction, including primary obstructing megaureter [52,66-68]. Approximately 5% to 10% of antenatal hydronephrosis is attributable to primary megaureter [4,69] diagnosed by persistent ureteral dilation (>7 mm). Primary megaureter is classified according to the presence or absence of reflux and obstruction. Most will resolve spontaneously [20,70-72]. Surgical intervention is decided based on evidence of obstruction and depends upon T1/2 of time activity curve (T1/2 >20 minutes), decreased renal function (<40% differential renal function), deteriorating function (>5% change on consecutive renal scans), or worsening drainage on serial imaging. Tc-99m MAG3 renal scan can be used to monitor function over time, with a decrease in differential renal function on the affected side often serving as an indicator of a need for intervention [55,73].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MRI Abdomen and Pelvis There is no consensus on the role of MRU, performed without and with intravenous (IV) contrast, in patients with moderate to severe postnatal hydronephrosis especially before VCUG is performed. Although MRU is not routinely recommended in the initial workup of antenatal hydronephrosis, some authors have argued that it can add value through improved anatomical imaging, for example, in the evaluation of hydronephrosis in the setting of atypical urinary tract anatomy, such as certain duplicated collecting systems or renal dysgenesis [74]. MRU can also adequately assess degree of obstruction [75]. One potential limitation of MRU is that there are systematic differences in estimation of split renal function compared with the gold standard MAG-3 renal scan in kidneys with severely diminished renal function [75] and kidneys with severe hydronephrosis [76].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. VUR can be either primary or secondary to other urologic abnormalities. In patients with moderate or severe hydronephrosis found on neonatal US, VCUG has a role in the evaluation of urologic abnormalities that may need immediate care [12,20,28,29,50,57]. Furthermore, it can reveal other anomalies, such as a duplex collecting system, which help to determine whether the reflux is primary or secondary.


Antenatal Hydronephrosis Infant


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Nuclear Medicine Cystography Some studies have suggested equal sensitivity for Tc-99m pertechnetate radionuclide cystography and VCUG [46], whereas others have indicated that radionuclide cystography has improved sensitivity for VUR in infants up to 1 year of age [47]. Arguments for and against using radionuclide cystography are similar to that of VCUG for the female patient.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Diuretic renal scan is used for diagnosis of multiple causes of obstruction, including primary obstructing megaureter [52,66-68]. Approximately 5% to 10% of antenatal hydronephrosis is attributable to primary megaureter [4,69] diagnosed by persistent ureteral dilation (>7 mm). Primary megaureter is classified according to the presence or absence of reflux and obstruction. Most will resolve spontaneously [20,70-72].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Surgical intervention is decided based on evidence of obstruction and depends upon T1/2 of time activity curve (T1/2 >20 minutes), decreased renal function (<40% differential renal function), deteriorating function (>5% change on consecutive renal scans), or worsening drainage on serial imaging. Tc-99m MAG3 renal scan can be used to monitor function over time, with a decrease in differential renal function on the affected side often serving as an indicator of a need for intervention [55,73].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MRI Abdomen and Pelvis There is no consensus on the role of MRU, performed without and with IV contrast, in patients with moderate to severe postnatal hydronephrosis especially before VCUG is performed. Although MRU is not routinely recommended in the initial workup of antenatal hydronephrosis, some authors have argued that it can add value through improved anatomical imaging, for example, in the evaluation of hydronephrosis in the setting of atypical urinary tract anatomy, such as certain duplicated collecting systems or renal dysgenesis [74]. MRU can also adequately assess degree of obstruction [75]. One potential limitation of MRU is inaccurate estimation of split renal function compared with renal scan in kidneys with severely diminished renal function [75] and kidneys with severe hydronephrosis [76].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. should be considered [6,29,53,77]. Of the causes of hydronephrosis, UPJO accounts for approximately 10% to 65% of cases and in 90% of cases the obstruction is unilateral [2,4,22,48]. As the severity of hydronephrosis increases, the risk of UPJO also increases, and as much as 35% of significant hydronephrosis (>10 mm APRPD postnatally) was attributable to UPJO in one study. Lee et al [51] showed a 54% risk of UPJO in severe (>15 mm APRPD postnatally) urinary tract dilation. Even in the setting of abnormal findings on initial neonatal US, further follow- up US between 1 and 6 months may be useful to re-evaluate a dilated urinary tract after bladder catheterization [1,21,23,53-55].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. DTPA Renal Scan Tc-99m DTPA is excreted primarily by glomerular filtration. Its extraction fraction is approximately 20% accounting for greater background, versus renal, activity compared to MAG3 [61]. Tc-99m DTPA renal scan provides information on renal function and urinary tract drainage based on split renal function and renal washout curves and can be useful for the evaluation of severe grade 3 and 4 hydronephrosis [20,29,53,62,63]. Given the lower glomerular filtration rate in newborns, these examinations are frequently delayed until at least 2 months of age [29,63-65]. However, because of its rapid renal clearance and primary excretion by the tubules on which furosemide acts, Tc-99m MAG3 is preferred over Tc-99m DTPA in patients with suspected obstruction or impaired renal function [61].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MAG3 Renal Scan Tc-99m MAG3 is primarily excreted through active renal tubular transport, and its extraction fraction is 40% to 50%. This greater extraction fraction, versus DTPA, accounts for less background, versus renal, activity compared to DTPA. Because of its rapid renal clearance and primary excretion by the tubules on which furosemide acts, Tc- 99m MAG3 is preferred over Tc-99m DTPA in patient with suspected obstruction or impaired renal function [61]. Tc-99m MAG3 renal scan provides information on split renal function and urinary tract drainage based on renal washout curve [3,22,27,28].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Surgical intervention is decided based on evidence of obstruction based on T1/2 of time activity curve (T1/2 >20 minutes), decreased renal function (<40% differential renal function), deteriorating function (>5% change on consecutive renal scans), or worsening drainage on serial imaging [55,73]. Tc-99m MAG3 renal scan can be used to monitor function over time, with a decrease in differential renal function on the affected side often serving as an indicator of a need for intervention [55,73].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. MRI Abdomen and Pelvis There is no consensus on the role of MRU, performed without and with IV contrast, in patients with moderate to severe postnatal hydronephrosis. Although MRU is not routinely recommended in the initial workup of antenatal hydronephrosis, some authors have argued that it can add value through improved anatomical imaging, for example, in the evaluation of hydronephrosis in the setting of atypical urinary tract anatomy, such as certain duplicated collecting systems or renal dysgenesis [74]. MRU can also adequately assess degree of obstruction [75]. One potential limitation of MRU is that there are systematic differences in estimation of split renal function compared with renal scan in kidneys with severely diminished renal function and kidneys with severe hydronephrosis [76].


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. 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.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Antenatal Hydronephrosis Infant

Antenatal Hydronephrosis Infant. Appropriateness Category Names and Definitions Relative Radiation Level Information Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level (RRL) indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate population total radiation risk associated with an imaging procedure. Patients in the pediatric age group are at inherently higher risk from exposure, because of both organ sensitivity and longer life expectancy (relevant to the long latency that appears to accompany radiation exposure). For these reasons, the RRL dose estimate ranges for


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Special Imaging Considerations In 2018, Schulz-Wendtland et al [25] first described a technique combining digital breast tomosynthesis (DBT) and ductography and evaluated 5 women with pathologic nipple discharge. They found that DBT-ductography performed comparably to high-resolution ultrasound (US) in identifying suspicious imaging lesions. In 2020 Moschetta et al [26] used this nascent technique on 49 consecutive patients with spontaneous, unilateral, single- pore discharge and inconclusive conventional digital mammography and US. In this series, they compared DBT-


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Reprint requests to: publications@acr.org


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Evaluation of Nipple Discharge


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. ductography with conventional full-field galactography and found improved sensitivity (95% versus 77%) and accuracy (96% versus 80%) with identical specificity (80%).


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. OR Discussion of Procedures by Variant Variant 1: Adult female or male or transfeminine (male-to-female) or transmasculine (female-to-male). Physiologic nipple discharge. Initial imaging. Physiologic nipple discharge is defined as bilateral, originating from multiple ducts, white/green/yellow in color, or milky in appearance [27]. It tends to occur only when provoked [8]. Many studies have shown physiologic nipple discharge to be benign, with no association within situ or invasive carcinoma [9,28,29].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Mammography Diagnostic If patient history and physical examination demonstrate physiologic nipple discharge and routine screening mammography is up to date, no further radiologic investigation is needed [28,29].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Digital Breast Tomosynthesis Diagnostic If patient history and physical examination demonstrate physiologic nipple discharge and routine screening mammography is up to date, no further radiologic investigation is needed [28,29].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. US Breast If patient history and physical examination demonstrate physiologic nipple discharge and routine screening mammography is up to date, no further radiologic investigation is needed [28,29].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Ductography If patient history and physical examination demonstrate physiologic nipple discharge and routine screening mammography is up to date, no further radiologic investigation is needed [28,29].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. MRI Breast If patient history and physical examination demonstrate physiologic nipple discharge and routine screening mammography is up to date, no further radiologic investigation is needed [28,29].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. FDG-PET Breast Dedicated If patient history and physical examination demonstrate physiologic nipple discharge and routine screening mammography is up to date, no further radiologic investigation is needed [28,29].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Image-guided Core Biopsy Breast Image-guided core biopsy is not required for the evaluation of physiologic nipple discharge in the female patient.


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Image-Guided Fine Needle Aspiration Breast Image-guided fine-needle aspiration (FNA) is not required for the evaluation of physiologic nipple discharge in the female patient.


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Sestamibi MBI If patient history and physical examination demonstrate physiologic nipple discharge and routine screening mammography is up to date, no further radiologic investigation is needed [28,29].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Evaluation of Nipple Discharge Variant 2: Adult male or female 40 years of age or older. Pathologic nipple discharge. Initial imaging. Mammography Diagnostic Mammography is the first-line imaging modality for evaluation of pathologic nipple discharge in male and female patients in this age group [30]. Although 3% to 29% of pathologic nipple discharge is due to an underlying breast cancer, full-field mammography often does not demonstrate these lesions because they may be very small, contain no calcifications, or are completely intraductal [1-3]. To better evaluate the subareolar breast in patients with an asymmetry/focal asymmetry or suspicious microcalcifications, additional mammographic views with spot compression and magnification may be needed [31].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Most cases of pathologic nipple discharge are due to a benign intraductal papilloma [32]. When visible on mammography, imaging findings of papilloma include asymmetrically dilated ducts, a circumscribed benign- appearing subareolar mass, or grouped microcalcifications [1]. Up to 12% of patients with ductal carcinoma in situ (DCIS) present with nipple discharge [33]. DCIS is usually detected mammographically as fine, linear, discontinuous, and branching microcalcifications in linear, ductal, or segmental distribution and less often as a mass, asymmetry/focal asymmetry, or architectural distortion on mammography [11]. The mammographic features of invasive carcinomas are well known, including a mass of various margin characteristics with or without microcalcifications or an asymmetry, focal asymmetry, or architectural distortion [34].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. For detection of malignancy (DCIS and invasive cancer), the reported sensitivity of mammography varies widely between 15% and 68%, with a specificity between 38% and 98% [3,9,23,28]. In one study, the positive predictive value (PPV) was 42%, and the negative predictive value (NPV) was 90% [23]. Malignant and high-risk lesions are identified by mammography with a reported sensitivity of 10% to 26%, specificity of 94% to 95%, PPV of 18%, and NPV of 88% [3,16]. The possible causes of the wide variation in reported sensitivity include differences in imaging technology (digital versus film-screen mammography) and varied breast density among different cohorts of patients.


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. In a study of 106 patients >30 years of age with pathologic nipple discharge, Gray et al [28] showed the risk of carcinoma to be 3% with a negative mammogram and 0% when both mammogram and subareolar US were negative. Although low in sensitivity and PPV, mammography remains useful in the evaluation of pathologic nipple discharge because of its high specificity and high NPV.


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Digital Breast Tomosynthesis Diagnostic Although there is no relevant literature to support the use of DBT alone in assessing nipple discharge, mammography is useful for evaluating pathologic nipple discharge in male and female patients in this age group [30]. Early studies with DBT demonstrate promise is assessing the symptomatic breast [35,36].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. US Breast US is useful in identifying invasive cancer and assessing extent of disease but has a diminished sensitivity for detecting DCIS [9,12,37,38]. In patients with pathologic nipple discharge, US identifies lesions not visible on mammography 63% to 69% of the time [30,39]. US adds specificity for some lesions when compared with mammography if it identifies the mammographic finding as a simple cyst or duct ectasia. US expands on ductography in its ability to visualize and detect abnormalities in multiple rather than single ducts [24].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Although more sensitive than mammography, US suffers from lower specificity in differentiating benign versus malignant lesions [9]. False-positive US results may be due to volume averaging with the ductal wall in a tortuous duct, intraductal and periductal fibrosis, adherent blood clots, or inspissated debris [31]. Previous studies have also reported mammography and US to be unreliable in predicting histology in patients with pathologic nipple discharge, which underscores the necessity of histological diagnosis [17,23]. In male and female patients, US is useful in identifying and assessing lesions and for biopsy guidance [40].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Ductography Ductography may demonstrate small lesions and localize the duct responsible for the nipple discharge. Ductography is minimally invasive, may be uncomfortable, and can be time-consuming. The procedure is technically challenging with 10% to 15% of cases resulting in inadequate or incomplete results [41,42]. The discharge must be present on


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Evaluation of Nipple Discharge


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. the day of ductography so that a cannula can be placed in the appropriate duct. Failure to cannulate the discharging duct may lead to a false negative [43]. Ductography is not recommended in lactating women or patients with active mastitis. Known hypersensitivity to iodinated contrast agents is a relative contraindication. Findings on ductography suggestive of malignant or papillary lesions include intraductal filling defect, partial or complete obstruction of a duct, duct expansion or distortion, and duct wall irregularity [1].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. In patients with pathologic nipple discharge and a negative mammogram and US, Morrogh et al [44] reported the PPV and NPV of ductography for detection of cancer and high-risk lesions to be 19% and 63%, respectively. In the setting of negative standard evaluations, ductography localized 76% of otherwise occult malignant/high-risk lesions and 91% of benign lesions [39]. When the standard evaluation is positive, ductography facilitated preoperative localization of the causative lesion in 78% of cases [39]. For detection of cancer in patients with pathologic nipple discharge, 2 studies showed the sensitivity, specificity, PPV, and NPV of ductography to be 75% to 100%, 6% to 49%, 16% to 18%, and 93% to 100%, respectively [16,23]. For detection of high-risk lesions, Adepoju et al [16] reported the sensitivity, specificity, PPV, and NPV of ductography to be 75%, 53%, 22%, and 92%, respectively.


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Ductography is more sensitive than mammography and US but has lower specificity than both modalities. A negative ductogram does not reliably exclude an underlying cancer or high-risk lesion, with the false-negative rate reported to be as high as 20% to 30% [44]. As such, the primary value of ductography is to localize intraductal lesions and assist in surgery [45]. A study found that patients who underwent ductography-guided operations or any other surgical procedure with image guidance of the lesion were significantly more likely to have a specific underlying lesion identified than patients who underwent central duct excision alone [23,42].


Evaluation of Nipple Discharge

Evaluation of Nipple Discharge. Contrast-enhanced breast MRI has high sensitivity for detecting benign papillary lesions as well as in situ and invasive carcinoma [3]. Furthermore, MRI allows identification of index lesions in peripheral ducts that are beyond the area normally encompassed by terminal duct excision, ductography, or targeted US [44]. Index or synchronous lesions found on MRI alone can be percutaneously biopsied with MRI guidance to allow for single-stage definitive surgical management (if malignant) or potentially to avoid unnecessary surgical excision for some benign lesions.