Noncerebral Vasculitis

Noncerebral Vasculitis. MRI and MRA In LVV, body MRI or MR angiography (MRA), including the chest, abdomen, and pelvis, can be performed to assess vasculitic changes [16]. MRI and MRA sequences are the following: T2-weighted fast spin-echo sequence or inversion recovery sequences, such as short-tau inversion recovery to display edema in the vessel wall; ECG- gated rapid 3-D T1-weighted spoiled gradient-echo pulse sequences can be used for MRA with gadolinium-based agents and maximum-intensity projection reformats; and postcontrast T1-weighted imaging with fat suppression (preferably using the Dixon technique) can be acquired throughout the body. Recently, new sequences have been introduced for LVV diagnosis, such as navigated T1-weighted 3-D black-blood fast turbo spin-echo sequence, which can acquire pre- and postcontrast isotropic 3-D images [17,18]. Last, the ECG-triggered balanced steady- state free-precession sequence provides additional information regarding the aortic root. Gadolinium injection through the veins can create susceptibility artifact along the axillary and subclavian arteries; therefore, maximum- intensity projection images should be examined carefully, and delayed images should be correlated [19].


Noncerebral Vasculitis

Noncerebral Vasculitis. There is a growing body of literature on high-resolution cranial MRI of the superficial cranial arteries for the diagnosis of c-GCA [20,21]. A 4-point ranking scale is used to classify the affected vessels based on the wall thickness and mural contrast enhancement [20,21]. Although this can be acquired practically during body MRI/MRA studies, discussion of this modality is not in the scope of this manuscript.


Noncerebral Vasculitis

Noncerebral Vasculitis

Noncerebral Vasculitis. Noncerebral Vasculitis


Noncerebral Vasculitis

Noncerebral Vasculitis. US and Color Doppler US US or color duplex US is a noninvasive imaging modality that has been used in the diagnosis of vasculitis. Particularly, in patients with suspected c-GCA, US/doppler US is recommended as the primary imaging modality [22]. Upper- and lower-extremity US can be added to increase diagnostic yield [23]. However, evaluation of the thoracic and abdominal vasculature is limited with US. Most of the literature on US is focused on its use in the temporal artery and, to a lesser extent, the extremity arteries. There is limited information regarding the use of chest, abdomen, and pelvis US or the diagnosis of LVV.


Noncerebral Vasculitis

Noncerebral Vasculitis. CTA or CT with IV contrast can be combined with FDG-PET as a hybrid model for the early diagnosis of LVV [32-34]. In 1 study, the authors compared CTA with FDG-PET/CT and found that the sensitivity and specificity of CTA for diagnosing GCA were 73% and 78%, respectively, and that the negative predictive value (NPV) and positive predictive value (PPV) were 65% and 85%, respectively [35]. Other studies compared the diagnostic performance of CTA to FDG-PET/CT, and both procedures were similarly able to detect large-vessel involvement in GCA [34,36,37]. In the study by de Boysson et al [36] , CTA demonstrated high sensitivity of 95% and specificity of 100% when comparing the diagnosis per patient. However, when the diagnosis was compared per segments of the aorta and branches, FDG-PET/CT was more sensitive for the detection of inflammation, and CTA had lower sensitivity (61%) but still high specificity (98%). Two relatively small studies comparing contrast-enhanced CT and FDG-PET demonstrated comparable results, with a slightly superior diagnostic accuracy of FDG-PET [34,38]. In addition, FDG-PET demonstrated a strong correlation with the inflammatory markers [38]. For TAK diagnosis (not necessarily active disease), sensitivity of 95% and specificity of 100% were demonstrated to be higher with CTA [39,40].


Noncerebral Vasculitis

Noncerebral Vasculitis


Noncerebral Vasculitis

Noncerebral Vasculitis. A prospective study showed that almost 49% of patients had persistent wall thickening despite demonstrating a complete clinical response to treatment. Therefore, the role of CTA in disease monitoring and response to treatment of LVV remains unclear [39].


Noncerebral Vasculitis

Noncerebral Vasculitis. CTA Coronary Arteries Coronary CTA is an ideal imaging modality for detecting coronary involvement in LVV, particularly in patients with TAK [41]. Kang et al [41] reported that 53.2% of patients with TAK had coronary arterial lesions on coronary CTA, regardless of disease activity or symptoms. Of these patients, 28% had coronary ostial stenosis, 36.9% had nonostial coronary arterial stenosis, and 8.1% had coronary artery aneurysm.


Noncerebral Vasculitis

Noncerebral Vasculitis. The sensitivity and specificity of the FDG-PET/CT to diagnose LVV is considerably high, ranging from 75% to 90% and from 81% to 98%, respectively, when the American College of Rheumatology criteria are used as a reference standard [42,46,49,50]. As mentioned above, the American College of Rheumatology criteria depend on temporal artery biopsy to detect c-GCA. However, in an extensive study, Luqmani et al [51] demonstrated that temporal artery biopsy has a false-negative rate as high as 61%. Therefore, the specificity of FDG-PET/CT in some studies was likely artificially lowered, considering temporal artery biopsy was falsely negative in extracranial GCA [52].


Noncerebral Vasculitis

Noncerebral Vasculitis. In their study, Lariviere et al [35] demonstrated that both FDG-PET/CT and CTA have a strong diagnostic yield to diagnose LVV; however, FDG-PET/CT appears to have higher PPV (100%) than CTA (84.6%). Similarly, another study found comparable sensitivity and specificity for FDG-PET/CT and CTA for the diagnosis of LVV [36]. However, per segments of the aorta and branches, FDG-PET/CT was significantly more sensitive than CTA (98% versus 61%) [36,37]. In a small study, the FDG-PET/CT score (visual and quantitative) was noted to be slightly superior to contrast-enhanced CT, with a strong correlation between the inflammatory markers [38]. Similarly,


Noncerebral Vasculitis

Noncerebral Vasculitis. Noncerebral Vasculitis another study comparing contrast-enhanced CT and FDG-PET revealed that FDG-PET/CT demonstrated excellent accuracy, whereas contrast-enhanced CT mural thickening exhibited good accuracy for the diagnosis of LVV [34].


Noncerebral Vasculitis

Noncerebral Vasculitis. A large prospective study comparing FDG-PET/CT and MRA demonstrated that FDG-PET/CT provides more information about disease activity, although MRA reveals anatomical changes and vascular damage [53]. Einspieler et al [54] investigated the performance of FDG-PET/MRI in patients with LVV. They assessed the individual value of FDG-PET and MRI, as well as compared FDG-PET/CT with FDG-PET/MRI. The authors concluded that FDG- PET/MRI and FDG-PET/CT produce consistent results and are highly comparable modalities. Similar to earlier studies, FDG-PET detected more abnormal vascular segments than MRA.


Noncerebral Vasculitis

Noncerebral Vasculitis. In addition, disease activity assessment by PET was associated with the clinical assessment. It has been shown that FDG-PET/CT also has prognostic value in patients with LVV [55,56]. In a multicenter study of 130 patients, inflammation in the aorta on FDG-PET/CT studies was reported to be a risk factor for aortic complications, particularly aneurysmal dilation or dissection [55]. FDG-PET/CT also may predict the long-term clinical outcome of patients with LVV. Two studies demonstrated that increased intensity of FDG uptake and extensive involvement of the vessels appeared to predict a less favorable response to treatment and more likely relapse during the follow- up, although the number of patients was small [46,57].


Noncerebral Vasculitis

Noncerebral Vasculitis. As mentioned earlier, PMR can be isolated or can occur in tandem with GCA and is often diagnosed based on symptoms. However, it is known that FDG-PET/CT can also demonstrate PMR as FDG uptake in the periarticular and extra-articular structures [65]. Interestingly, a recent study has reported that many patients without cranial symptoms (ie, isolated PMR) often demonstrated LVV on FDG-PET/CT [66]. In addition to PMR, FDG-PET/CT can detect other extravascular findings (such as malignancy or infection) in patients who present with constitutional symptoms similar to vasculitis [13].


Noncerebral Vasculitis

Noncerebral Vasculitis. In a recent prospective cohort study of patients with suspected LVV, particularly GCA, patients underwent head, neck, and chest FDG-PET/CT. The sensitivity and specificity for the diagnosis of superficial cranial artery vasculitis were reported to be 92% and 91%, respectively, when the temporal artery biopsy was used as a reference test [14]. A similar study was performed by Nielsen et al [15], who demonstrated FDG uptake in the head and neck vessels with a high sensitivity and specificity and concluded that temporal artery biopsy could be omitted. There is also a prognostic value of head and neck FDG-PET/CT, particularly in the vertebral arteries, associated with the risk of ischemic complications [67]. A study by Michailidou et al [68] demonstrated that a pattern of FDG uptake along the head and neck vasculature can help differentiate TAK from GCA involvement without any angiographic abnormalities on MRA images. Patients with TAK present predominantly with carotid artery involvement, whereas more involvement is noted in the posterior cervical circulation (vertebral arteries) in patients with GCA. However, the authors assessed only for arterial damage on MRA, such as aneurysm, stenosis, and occlusion.


Noncerebral Vasculitis

Noncerebral Vasculitis. The main concern with FDG-PET/CT is that its sensitivity is affected by immunosuppression [42,69,70]. In addition, patients receiving glucocorticoid treatment demonstrate an increase in FDG uptake in the liver, which can lower the diagnostic accuracy when the vessel wall and liver ratio are used [42]. A study showed lower sensitivity


Noncerebral Vasculitis

Noncerebral Vasculitis. MRA Chest, Abdomen, and Pelvis Although MRA is considered an ideal imaging modality for vessel wall evaluation with its high tissue resolution ability, the literature on LVV diagnosis is limited.


Noncerebral Vasculitis

Noncerebral Vasculitis. In a recent study involving 75 patients, when the authors used the temporal artery biopsy as the reference test, the sensitivity and specificity of MRA to diagnose LVV was 79% and 96%, respectively [73]. In the same study, PPV and NPV were 92% and 88%, respectively [73]. However, in a meta-analysis to diagnose TAK only, the pooled sensitivities and specificities were as high as 92% [29]. In addition, another study found that the use of whole-body contrast-enhanced MRA in patients with TAK was useful to diagnose active versus inactive TAK [74]. Similar to CTA, wall thickening and enhancement of the vessel wall on MRA were considered good markers of disease activity [29]. Per EULAR recommendations, MRA was considered as a first imaging modality for patients with TAK, considering the age of this population [22]. Interestingly, a prospective study by Quinn et al [53], demonstrated that MRA identified a greater extent of vascular involvement than PET because MRA can detect both arterial wall abnormalities (wall thickness and edema) and luminal abnormalities (aneurysm, stenosis, and occlusion). However, when investigators assessed disease activity, the interrater agreement was greater for PET scan reads than for MRA reads (kappa = 0.84 versus 0.58), indicating that assessment of disease activity by PET is more reliable than MRA. In that study, the authors found that vascular thickness and vascular edema on short-tau inversion recovery sequences were independently associated with the global FDG-PET/CT study interpretation on disease activity [53]. In another study, Einspieler et al [54] demonstrated consistent results between the use of FDG-PET/MRI and FDG- PET/CT. In that study, when FDG-PET and MRI were evaluated independently by an imaging physician, more abnormal vascular segments were detected on FDG-PET [54]. The use of T2-weighted sequences to assess disease activity is controversial in the literature; thus, the EULAR recommendation suggests that edema on T2-weighted images is less sensitive and prone to artifacts [22,75,76].


Noncerebral Vasculitis

Noncerebral Vasculitis. MRI Chest, Abdomen, and Pelvis An extensive literature search revealed that isolated MRI without angiography (MRA) is limited to a study by Kato et al [76]. In this study, the authors performed the late gadolinium enhancement sequence after contrast injection to the patients with TAK to assess disease distribution and activity of vessel wall inflammation. They concluded that the late gadolinium enhancement sequence has utility in detecting the extent; however, disease activity may be difficult to determine using late gadolinium enhancement alone.


Noncerebral Vasculitis

Noncerebral Vasculitis. MRA Coronary Arteries There is no relevant literature to support the use of MRA coronary arteries in the diagnosis of LVV.


Noncerebral Vasculitis

Noncerebral Vasculitis. MRA Neck There is no isolated or specific literature to support the use of MRA of the neck in the diagnosis of LVV. However, a recent study by Michailidou et al [68] demonstrated that neck MRA can be used along with chest MRA. However, the authors used MRA to assess vascular damage, such as aneurysm, stenosis, or occlusion.


Noncerebral Vasculitis

Noncerebral Vasculitis. MRI Heart Function and Morphology There is no relevant literature to support the use of MRA of the coronary arteries in the diagnosis of LVV.


Noncerebral Vasculitis

Noncerebral Vasculitis. US Duplex Doppler Aorta Abdomen There is a lack of evidence in the literature for the use of US duplex Doppler abdominal aorta in the diagnosis of LVV. US can be used in the assessment of and screening for abdominal aortic aneurysm. Although the abdominal aortic wall can be visualized with US, again, there is lack of evidence in the literature regarding the use of US for the diagnosis of vasculitis. One study by Loffler et al [77], in which FDG-PET/CT was used a reference test, sensitivity of US for LVV was demonstrated to be 26%.


Noncerebral Vasculitis

Noncerebral Vasculitis. US Duplex Doppler Chest, Abdomen, and Pelvis There is a lack of evidence in the literature for the use of US chest, abdomen, and pelvis in the diagnosis of LVV. In particular, thoracic aorta evaluation with US is hampered by the lungs [78]. US can be used in the assessment of


Noncerebral Vasculitis

Noncerebral Vasculitis

Noncerebral Vasculitis. Noncerebral Vasculitis


Noncerebral Vasculitis

Noncerebral Vasculitis. and screening for abdominal aortic aneurysm. Although the abdominal aortic wall can be visualized with the US, again, there is lack of evidence in the literature regarding the use of US for the diagnosis of vasculitis.


Noncerebral Vasculitis

Noncerebral Vasculitis. In a study by Loffler et al [77], in which FDG-PET/CT was used as a reference test, the sensitivity and specificity of US for the diagnosis of LVV were 80% and 70%, respectively (PPV 80%, NPV 70%). In their study, when authors analyzed separately, sensitivities of US for LVV diagnosis in the axillary and subclavian arteries were 72% and 71%, respectively. In TAK vasculitis, US can demonstrate a wide range of imaging findings, including hypoechoic rim/halo sign and hyperechoic rim around the vessel wall [83]. Although the echogenicity of the vessel wall is not helpful in distinguishing between acute or chronic inflammatory changes, it has been reported that active areas tend to have a thicker vessel wall [23]. A study demonstrated a good correlation between contrast-enhanced US and FDG-PET/CT findings [84]. Regarding the prognostic value of US, a study by Czihal et al [85] showed that concomitant temporal and upper-extremity vessel abnormality on US was associated with the poor treatment response in patients with GCA.


Noncerebral Vasculitis

Noncerebral Vasculitis. US Duplex Doppler Lower Extremity There are limited data in the literature for the use of US duplex Doppler lower extremity in the diagnosis of LVV. In a study by Loffler et al [77], in which FDG-PET/CT was used a reference test, sensitivity of US for LVV diagnosis in the common femoral arteries was demonstrated to be 17%.


Noncerebral Vasculitis

Noncerebral Vasculitis. US Duplex Doppler Iliofemoral Arteries There is a lack of evidence in the literature for the use of US duplex Doppler iliofemoral arteries in the diagnosis of LVV.


Noncerebral Vasculitis

Noncerebral Vasculitis. Variant 2: Suspected medium-vessel vasculitis (MVV). Initial imaging. Arteriography Chest, Abdomen, and Pelvis Although digital subtraction angiography has lost its role as a diagnostic method for confirming a clinically suspected diagnosis of LVV, it is still a crucial modality in the diagnosis of MVV. Classic imaging findings in PAN are microaneurysms [86]. Similarly, for Kawasaki disease, catheter angiography is considered to be an ideal imaging modality [87].


Noncerebral Vasculitis

Noncerebral Vasculitis. CTA Chest, Abdomen, and Pelvis There is limited literature on the use of CTA to diagnose MVV. Singhal et al [88] reported positive CTA studies in 15 of 27 patients with PAN. The most common CTA finding was aneurysm, followed by stenosis/occlusion, and the renal artery was the most commonly involved artery [89]. Splenic and renal infarcts were the most visceral abnormalities. Therefore, CTA can be utilized in the diagnosis of the MVV.


Noncerebral Vasculitis

Noncerebral Vasculitis. CT Chest, Abdomen, and Pelvis There are sparse studies on the use of CT to diagnose MVV. CT of the chest, abdomen, and pelvis is an ideal imaging modality to assess end organ abnormalities in patients with MVV. A study by Singhal et al [88] reported splenic and renal infarcts were the most visceral abnormalities.


Noncerebral Vasculitis

Noncerebral Vasculitis. CTA Coronary Arteries Considering that Kawasaki disease targets the coronary arteries, there is a significant role for CTA in the diagnosis and follow-up of these patients [7,90]. However, there is a lack of evidence in the literature for the use of CTA coronary arteries in adult population.


Noncerebral Vasculitis

Noncerebral Vasculitis. FDG-PET/CT Whole Body FDG-PET/CT can assess relatively large vessels, so its usefulness in assessing MVV is limited [91].


Noncerebral Vasculitis

Noncerebral Vasculitis


Noncerebral Vasculitis

Noncerebral Vasculitis. MRA Chest, Abdomen, and Pelvis There is no relevant literature to support the use of MRA chest, abdomen, and pelvis in the diagnosis of the MVV. However, similar to CT chest, abdomen, and pelvis, MRA can be utilized in MVV to assess parenchymal changes of the visceral organs when there is a clinical concern.


Noncerebral Vasculitis

Noncerebral Vasculitis. MRI Chest, Abdomen, and Pelvis There is no relevant literature to support the use of MRI chest, abdomen, and pelvis in the diagnosis of the MVV. However, similar to CT chest, abdomen, and pelvis, MRI can be utilized in MVV to assess parenchymal changes of the visceral organs when there is a clinical concern.


Noncerebral Vasculitis

Noncerebral Vasculitis. MRA Coronary Arteries There is no relevant literature to support the use of MRA coronary arteries in the diagnosis of the LVV. However, there are some case reports describing the usage of coronary MRA in Kawasaki disease.


Noncerebral Vasculitis

Noncerebral Vasculitis. MRA Neck There is no relevant literature to support the use of MRA neck in the diagnosis of MVV.


Noncerebral Vasculitis

Noncerebral Vasculitis. MRI Heart Function and Morphology There is no relevant literature to support the use of MRI of the heart in the diagnosis of MVV. However, in the right clinical context (eg, Kawasaki disease), cardiac MRI can be utilized to assess complications.


Noncerebral Vasculitis

Noncerebral Vasculitis. US Duplex Doppler Aorta Abdomen There is no relevant literature to support the use of US duplex Doppler aorta abdomen in the diagnosis of MVV.


Noncerebral Vasculitis

Noncerebral Vasculitis. US Duplex Doppler Chest, Abdomen, and Pelvis There is no relevant literature to support the use of US duplex Doppler chest, abdomen, and pelvis in the diagnosis of MVV.


Noncerebral Vasculitis

Noncerebral Vasculitis. US Duplex Doppler Upper Extremity There is no relevant literature to support the use of US duplex Doppler upper extremity in the diagnosis of MVV.


Noncerebral Vasculitis

Noncerebral Vasculitis. US Duplex Doppler Lower Extremity There is no relevant literature to support the use of US duplex Doppler lower extremity in the diagnosis of MVV.


Noncerebral Vasculitis

Noncerebral Vasculitis. Noncerebral Vasculitis 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.


Noncerebral Vasculitis

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


Noncerebral Vasculitis

Noncerebral Vasculitis

Noncerebral Vasculitis. Noncerebral Vasculitis


Imaging after Total Hip Arthroplasty PCAs. Introduction/Background It has been approximately 60 years since Sir John Charnley introduced the modern era of hip replacement surgery [1]. Approximately 370,000 primary total hip arthroplasties (THAs) were performed in the United States in 2014 [2]. Sloan et al [2] estimated that the volume of primary THAs would increase to 635,000 procedures annually by 2030.


Imaging after Total Hip Arthroplasty PCAs. Over the years, modifications have been made to attempt to decrease complications such as loosening and wear with additional fixation techniques (eg, osseointegration) and articular surfaces (eg, metal on highly cross-linked polyethylene, antioxidant doped polyethylene liners, metal-on-metal [MoM], ceramic on polyethylene, and ceramic on ceramic articulations) [3-5].


Imaging after Total Hip Arthroplasty PCAs. The most common causes for surgical revision of THA from 2012 to 2019 as reported in the American Academy of Orthopaedic Surgeons American Joint Replacement Registry were infection and inflammatory reaction (19.3%), instability (17.4%), and aseptic loosening (15.8%) [15-17]. Wear or osteolysis was the cause for revision in 7.5%.


Imaging after Total Hip Arthroplasty PCAs. The imaging studies used to follow uncomplicated primary hip prostheses and to assess several prosthesis-related complications are reviewed. Separate discussions pertinent to imaging of MoM prostheses are included.


Imaging after Total Hip Arthroplasty PCAs. Special Imaging Considerations Ultrasound (US): US has been used for assessment of soft tissues adjacent to hip arthroplasties and, in contrast to MRI and CT, is not affected by prosthetic artifacts. US may be limited in its ability to assess deep soft tissues.


Imaging after Total Hip Arthroplasty PCAs. Metal artifact reduction sequences (MARS)-MRI: MARS-MRI enable soft tissues around the prosthetic hip such as the pseudocapsule, tendons, and neurovascular structures to be assessed. Reviews of some MARS-MRI techniques are available in the literature [18-21].


Imaging after Total Hip Arthroplasty PCAs. Metal artifact reduction (MAR)-CT: Metallic hip prostheses, particularly cobalt chrome components, produce artifacts on CT scanning that can obscure adjacent structures. As reviewed by Roth et al [22], these artifacts are related to both the prosthesis (eg, type of metal and geometry) and the scanning parameters. Several techniques have been used to reduce these artifacts (termed MAR) [22,23].


Imaging after Total Hip Arthroplasty PCAs. Fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT Skull Base to Mid-Thigh and Fluoride PET/CT Skull Base To Mid-Thigh: PET studies (using either FDG or fluoride) may be tailored to focus imaging of the area of interest,


Imaging after Total Hip Arthroplasty PCAs. Reprint requests to: publications@acr.org


Imaging After Total Hip Arthroplasty

Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty


Imaging after Total Hip Arthroplasty PCAs. such as the hip, rather than including the entire region of the skull base to mid-thigh. Many of the investigations included in this document were performed before the widespread availability of PET/CT, and consequently, they were performed as PET studies without CT.


Imaging after Total Hip Arthroplasty PCAs. Bone Scan Hip Periprosthetic uptake can be present for a year or more after prosthetic insertion [25-27]. Therefore, bone scintigraphy of the hip for routine surveillance of asymptomatic hip arthroplasties is not supported.


Imaging after Total Hip Arthroplasty PCAs. Bone Scan with SPECT or SPECT/CT Hip Data on the normal evolution of periprosthetic uptake on single-photon emission computed tomography (SPECT) or SPECT/CT of the hip following hip arthroplasty are lacking [28].


Imaging after Total Hip Arthroplasty PCAs. However, on planar bone scintigraphy, persistent periprosthetic uptake can be present for more than 1 year following implantation [25-27]. Consequently, bone scintigraphy with SPECT or SPECT/CT is not supported for routine surveillance of asymptomatic hip arthroplasties.


Imaging after Total Hip Arthroplasty PCAs. CT Hip There are no recent studies advocating routine CT scanning of the hip for asymptomatic patients with conventional or MoM prostheses.


Imaging after Total Hip Arthroplasty PCAs. Fluoride PET/CT Skull Base to Mid-Thigh It can take a year or more for periprosthetic uptake to normalize around a hip prosthesis [29,30]. Therefore, fluoride PET/CT skull base to mid-thigh is not supported for routine surveillance of asymptomatic hip arthroplasties.


Imaging after Total Hip Arthroplasty PCAs. MRI Hip MRI for asymptomatic non-MoM hips: MRI is generally not indicated in routine follow-up of asymptomatic patients with non-MoM prostheses. However, the MRI findings in asymptomatic patients are being investigated [19,31-33].


Imaging after Total Hip Arthroplasty PCAs. MARS-MRI for asymptomatic MoM prostheses: Pseudotumors consistent with ARMD have been reported on MRI in patients without pain following MoM arthroplasties [6,33-38]. Thus, MRI may be beneficial in this group.


Imaging after Total Hip Arthroplasty PCAs. In a series of MoM hip resurfacing arthroplasties, clinical outcomes and radiographic screening underestimated the presence of pseudotumors and supported the use of MRI for screening [38]. Similarly, Koff et al [33] performed 4 yearly MRI examinations of patients with surface replacement prostheses and found evidence of ALTRs in high- functioning individuals without pain. They concluded that MRI should be considered as part of the routine patient follow-up protocol to allow early detection and follow-up of ALTRs. In 2 series, comparison of MRI results to histologic findings showed the sensitivity of MRI for pseudotumors to be 85% and 71%, respectively, and the specificity to be 59% and 87%, respectively [39,40]. Sensitivity was greater when the MRI examination was performed within 3 months of the revision surgery (88%) [39].


Imaging After Total Hip Arthroplasty


Imaging after Total Hip Arthroplasty PCAs. Combined US and MARS-MRI studies: Comparison to surgical results suggests combining US and MARS-MRI improves accuracy. Small numbers of lesions detected on US are not visible on MRI, and some lesions seen on MRI are not apparent on US [35,36,41].


Imaging after Total Hip Arthroplasty PCAs. Radiography Hip Follow-up radiographs for asymptomatic non-MoM total hip prostheses: Radiographs have been the imaging mainstay for following THA [42]. Review of serial radiographs is useful for identifying subtle changes, emphasizing the need for baseline radiographs. However, Hart et al [43] followed postoperative patients with THAs undergoing routine follow-up, excluding patients with complications of fracture, dislocation, or infection or who had died. Of the 423 patients studied, 414 had radiographs at 6 to 12 weeks and 276 had follow-up radiographs at 1 year. No THA case was identified in which clinical management was changed by the radiographic examination in this time period. This suggested to the authors that, in asymptomatic patients, some follow-up radiographs might be omitted.


Imaging after Total Hip Arthroplasty PCAs. Radiographs for follow-up of asymptomatic MoM total hip prostheses: The FDA recommends routine long-term follow-up of patients with MoM hip implants, typically to occur every 1 to 2 years [44]. This includes appropriate radiographs. Serial radiographs are helpful to assess subtle changes [42]. Radiographs can be used to assess component position, component loosening, bone quality, osteolysis, fracture, dislocation or subluxation, femoral neck narrowing, and medial femoral calcar erosion [36,45]. The latter may be an indicator of ARMD, warranting cross-sectional imaging (positive predicative value [PPV] 0.83) [45].


Imaging after Total Hip Arthroplasty PCAs. US Hip US for follow-up of asymptomatic non-MoM total hip prostheses: A few studies have investigated US to assess asymptomatic patients with metal-on-polyethylene (MoP) bearings [41,46]. Nishii et al [41] concluded that US seemed a promising noninvasive tool for detection of ARMD pseudotumors. However, there are no recent studies indicating the use of US for routine surveillance of nonmetal on metal prostheses.


Imaging after Total Hip Arthroplasty PCAs. US for follow-up of asymptomatic MoM total hip prostheses: US may be beneficial as asymptomatic patients may show imaging changes of or associated with ARMD [46]. US can be used to detect pseudotumors (solid or cystic) and other findings seen with ARMD such as joint effusions, bursal collections, and synovitis [36,47-49]. Williams et al [46] proposed high-resolution US surveillance of all asymptomatic patients with a MoM implant that is known to result in high serum metal ion levels.


Imaging after Total Hip Arthroplasty PCAs. Low et al [50] prospectively followed 152 asymptomatic MoM hip resurfacing arthroplasties at a mean of 4.3 years using US. Progression of findings occurred in 19%, and new pseudotumors developed in 10%. No asymptomatic hip resurfacing arthroplasty patient with both a normal initial US and low blood metal ions (<2 ug/L) developed pseudotumors within 5 years of initial assessment, and, therefore, they concluded this patient subgroup did not require repeat follow-up within 5 years [50].


Imaging after Total Hip Arthroplasty PCAs. Comparison of US with MRI: A summary of studies comparing US to MARS-MRI as the reference standard for detecting ARMD shows sensitivities for US of 69% to 100% and specificities of 83% to 96% [36]. Kwon et al [52] found that US was valid and useful for detecting interval changes in lesion size and grade in comparison with MARS-MRI.


Imaging after Total Hip Arthroplasty PCAs. Combined US and MARS-MRI studies: Comparison to surgical results suggests combining US and MARS-MRI improves accuracy. Small numbers of lesions detected on US are not visible on MRI and some lesions seen on MRI are not apparent on US [36,41,52].


Imaging after Total Hip Arthroplasty PCAs. Variant 2: Symptomatic patient with hip prosthesis. Initial imaging. Bone Scan Hip There is insufficient evidence to support the use of bone scan of the hip as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty.


Imaging after Total Hip Arthroplasty PCAs. Bone Scan with SPECT or SPECT/CT Hip There is insufficient evidence to support the use of bone scans with SPECT or SPECT/CT of the hip as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty.


Imaging After Total Hip Arthroplasty

Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty


Imaging after Total Hip Arthroplasty PCAs. CT Hip There is insufficient evidence to support the use of CT of the hip as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty. A possible exception might be for detection of a ceramic acetabular liner fracture where case reports suggest CT to be more sensitive than radiographs [53].


Imaging after Total Hip Arthroplasty PCAs. Fluoride PET/CT Skull Base to Mid-Thigh There is insufficient evidence to support the use of fluoride PET/CT skull base to mid-thigh as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty.


Imaging after Total Hip Arthroplasty PCAs. Image-Guided Aspiration Hip There is no relevant literature to support the use of image-guided aspiration of the hip as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty.


Imaging after Total Hip Arthroplasty PCAs. MRI Hip Non-MoM hip prostheses: There is insufficient evidence to support the use of MRI of the hip as the initial imaging modality for the patient with a symptomatic non-MoM arthroplasty.


Imaging after Total Hip Arthroplasty PCAs. MoM hip prostheses: Because radiographs may be normal in patients with symptomatic pseudotumors [54], advanced imaging has been supported. Based on literature review, Petscavage-Thomas and Ha [49] suggested MARS-MRI as the first-line of imaging for detection of ARMD.


Imaging after Total Hip Arthroplasty PCAs. Radiography Hip Radiographs are usually the first imaging modality for assessment of a patient with a symptomatic hip prosthesis.


Imaging after Total Hip Arthroplasty PCAs. Non-MoM hip prostheses: The literature indicates that radiographs are usually the first imaging modality for assessment of a patient with a symptomatic hip prosthesis. Comparison radiographs are useful; however, an assessment of stem loosening on comparison studies may be suboptimal due to variables such as differences in hip flexion or rotation [55].


Imaging after Total Hip Arthroplasty PCAs. Some radiographic features such as increased femoral head and stem offset suggest the need for additional imaging for ARMD due to trunnionosis [56]. Metallosis may be identified around nonmetal on metal prostheses due to trunnionosis or following severe liner wear and/or liner dislocation or fracture [14,57-59]. However, Chang et al [14] found that in more than half of patients with surgically proven metallosis, radiographs did not show metal density in the soft tissues preoperatively.


Imaging after Total Hip Arthroplasty PCAs. Radiographs are neither sensitive nor specific for infection. Normal radiographs do not exclude infection; half of the patients in a series of 20 infected hip prostheses reviewed by Tigges et al were normal [60]. Lucencies suggesting aseptic loosening or focal osteolysis may be present in infected hips [60]. Progression of lucency may be rapid in cases of infection. Periostitis was seen in 2 cases.


Imaging after Total Hip Arthroplasty PCAs. Stumpe et al [61] reviewed radiographs of 35 patients with painful total hip replacements: 9 with septic, 21 with aseptic prosthetic loosening, and 5 without loosening. Rapid progression of osteolysis, rapid component migration, and/or irregular periprosthetic osteolysis were used to diagnose infection. For 2 readers, a sensitivity of 89% and 78%, specificity of 50% and 65%, and accuracy of 60% and 69% were found.


Imaging after Total Hip Arthroplasty PCAs. In a review, Fritz et al [18] noted that radiographs are usually the first imaging modality for patients with postoperative lateral hip pain. Radiographs help assess the presence of periprosthetic fractures, avulsions of the greater trochanter, and heterotopic ossification [18]. Radiographs showing >2 mm surface irregularities of the greater trochanter have been reported with abductor tendon abnormalities and peritendinous edema on MRI [62]. However, a review of 38 cases of greater trochanter pain syndrome and 100 controls showed the findings of trochanteric surface irregularities including spurs protruding 2 mm were associated with a 24.7% PPV, 64.0% sensitivity, 25.7% specificity, 74.3% false-positive rate, 36.0% false-negative rate, and 65.3% negative predicative value (NPV) for clinical greater trochanteric pain syndrome [63].


Imaging after Total Hip Arthroplasty PCAs. MoM hip prostheses: The FDA notes that in the symptomatic patient following insertion of a MoM prosthesis, radiographs in conjunction with nonimaging information, may disclose the need for revision [44]. Metallosis resulting from severe wear of a metal on metal articulation may occasionally be identified on radiographs [64]. Component position can be assessed [65].


Imaging after Total Hip Arthroplasty PCAs. Matharu et al [54] found hips with resurfacing arthroplasties and symptomatic pseudotumors were more likely than those without pseudotumors to have abnormal radiographs (80.0% compared with 63.4%). Radiographic features


Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty that predicted revision for pseudotumors included high inclination, acetabular or femoral osteolysis, and acetabular loosening. In that study, 20% of hip resurfacing prostheses with pseudotumors at revision surgery had normal radiographic features [54]. Based on these findings, Matharu et al [54] concluded that radiographs were important and useful in all follow-up protocols to assess MoM hip resurfacing prostheses. Petscavage-Thomas and Ha [49] concluded on literature review that cross-sectional imaging, particularly MRI, is still beneficial even in the presence of normal radiographs.


Imaging after Total Hip Arthroplasty PCAs. US Hip Non-MoM hip prostheses: There is insufficient evidence to support the use of US of the hip as the initial imaging modality for the patient with a symptomatic non-MoM prosthesis.


Imaging after Total Hip Arthroplasty PCAs. US for MoM hip prostheses: In a series of 82 hips (82 patients) undergoing revision of MoM prostheses, Lainiala et al [51] found the sensitivity of US examination to be 83% with a specificity of 92% for pseudotumors in the trochanteric region and a sensitivity of 79% and a specificity of 94% for identifying pseudotumors in the iliopsoas region.


Imaging after Total Hip Arthroplasty PCAs. Matharu et al [66] studied a series of 40 MoM hip resurfacing arthroplasties (39 patients) undergoing revision surgery who had preoperative imaging with both US and MARS-MRI. Comparison with operatively identified pseudotumors showed US to have a sensitivity of 90.9% and a specificity of 42.9% compared with an MRI sensitivity of 93.9% and a specificity 57.1%. The PPV was similar (88.2% US, 91.2% MRI) but the NPV was higher for MRI (66.7% on MRI, 50.0% for US) [66].


Imaging after Total Hip Arthroplasty PCAs. Variant 3: Symptomatic hip arthroplasty patient, history of acute injury. Additional imaging following radiographs. If a fracture is suspected clinically but is not demonstrated or not fully characterized on radiographs, additional imaging may be necessary. Fracture location, component stability (stable versus loose), and femoral bone stock are features that can influence management and that can be assessed on imaging [67-70].


Imaging after Total Hip Arthroplasty PCAs. Bone Scan and Gallium Scan Hip There is insufficient evidence to support the use of combined bone and gallium scan of the hip in the evaluation of the symptomatic hip prosthesis in the setting of acute injury.


Imaging after Total Hip Arthroplasty PCAs. Bone Scan and Gallium Scan With SPECT or SPECT/CT Hip There is insufficient evidence to support the use of combined bone and gallium scan with SPECT or SPECT/CT hip in the evaluation of the symptomatic hip prosthesis in the setting of acute injury.


Imaging after Total Hip Arthroplasty PCAs. Bone Scan Hip There is insufficient evidence to support the use of the bone scan of the hip in the evaluation of the symptomatic hip prosthesis in the setting of acute injury.


Imaging after Total Hip Arthroplasty PCAs. Bone Scan with SPECT or SPECT/CT Hip There is insufficient evidence to support the use of the bone scan with SPECT or SPECT/CT of the hip in the evaluation of the symptomatic hip prosthesis in the setting of acute injury.


Imaging after Total Hip Arthroplasty PCAs. CT Hip Nonenhanced multidetector CT of the hip has been suggested for fracture detection when radiographs are negative or equivocal and there is high suspicion for periprosthetic fracture or when additional fracture characterization is needed for treatment planning [22,70]. There is no relevant literature documenting additional benefit of CT with IV contrast, relative to noncontrast CT for fracture detection/assessment. Contrast may be helpful if there is a question of vascular injury [23].


Imaging after Total Hip Arthroplasty PCAs. The reported efficacy of CT to provide information regarding component loosening (for treatment planning) when a fracture is present is inconsistent [68,71]. Case reports suggest CT to be more sensitive than radiographs for detecting fracture of a ceramic liner [53].


Imaging after Total Hip Arthroplasty PCAs. FDG-PET/CT Skull Base to Mid-Thigh There is insufficient evidence to support the use of FDG-PET/CT skull base to mid-thigh in the evaluation of the symptomatic hip prosthesis in the setting of acute injury.


Imaging After Total Hip Arthroplasty

Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty


Imaging after Total Hip Arthroplasty PCAs. Fluoride PET/CT Skull Base To Mid-Thigh There is insufficient evidence to support the use of fluoride PET/CT skull base to mid-thigh in the evaluation of the symptomatic hip prosthesis in the setting of acute injury.


Imaging after Total Hip Arthroplasty PCAs. Image-Guided Aspiration Hip There is insufficient evidence to support the use of image-guided aspiration of the hip in the evaluation of the symptomatic hip prosthesis in the setting of acute injury.


Imaging after Total Hip Arthroplasty PCAs. MRI Hip MRI can demonstrate femoral periprosthetic fractures and stress reactions [18]. However, a nondisplaced fracture may be difficult to see on MRI if there is only mild associated marrow edema, and susceptibility artifact from the prosthesis may obscure the pertinent findings [72]. Pelvic fractures can be demonstrated. There is no relevant literature documenting the additional benefit of MRI with IV contrast, relative to noncontrast MRI, for fracture detection.


Imaging after Total Hip Arthroplasty PCAs. US Hip US is limited in its ability to detect periprosthetic fracture [73].


Imaging after Total Hip Arthroplasty PCAs. WBC Scan and Sulfur Colloid Scan Hip There is insufficient evidence to support the use of white blood cell (WBC) and sulfur colloid of the hip imaging in the evaluation of the symptomatic hip prosthesis in the setting of acute injury.


Imaging after Total Hip Arthroplasty PCAs. Variant 4: Symptomatic hip arthroplasty patient, infection not excluded. Additional imaging following radiographs. Ong et al [74] found the incidence of infection after THA in the Medicare population for 1997 and 2006 to be 1.63% within 2 years and 0.59% between 2 and 10 years. The identification of periprosthetic infection is critical to choosing appropriate treatment but diagnosis can be challenging [75]. Guidelines for patient evaluation have been developed [76]. A definition of periprosthetic infection has been proposed by the musculoskeletal infection society that includes major and minor criteria but not specifically imaging criteria [75].


Imaging after Total Hip Arthroplasty PCAs. Bone Scan and Gallium Scan Hip The most recent data on bone and gallium scans for diagnosing periprosthetic hip infection are more than 25 years old because this test has been largely replaced by labeled leukocyte and marrow imaging and FDG-PET [77-79].


Imaging after Total Hip Arthroplasty PCAs. Bone Scan and Gallium Scan with SPECT or SPECT/CT Hip There is no relevant literature to support the use of bone and gallium scan with SPECT or SPECT/CT of the hip as these tests have been replaced by leukocyte and bone marrow imaging and FDG-PET for diagnosing periprosthetic hip infection.


Imaging after Total Hip Arthroplasty PCAs. Bone Scan Hip Bone scan of the hip is sensitive but not specific for periprosthetic hip infection. Performing the test as a 3-phase bone scan does not improve accuracy, with reported sensitivity and specificity ranging from 29% to 88% and 50% to 92%, respectively [61,80-82].


Imaging after Total Hip Arthroplasty PCAs. Bone Scan with SPECT or SPECT/CT Hip Schweizer et al [83] retrospectively studied 58 total hip prostheses, including 31 symptomatic and 27 asymptomatic prostheses, with bone scan with SPECT/CT. SPECT/CT identified the cause of pain in 19 (61%) of the 31 symptomatic devices. No pathology-specific uptake pattern was observed. Although periprosthetic uptake was significantly higher in symptomatic individuals than in asymptomatic individuals, a normal result did not exclude pathology.


Imaging after Total Hip Arthroplasty PCAs. CT Hip In a 2002 study, Cyteval et al [84] prospectively reviewed helical noncontrast CT scans of 65 painful prosthetic hips with diagnosis confirmed by surgery. Infection was present in 12. Fluid collections in muscles and perimuscular fat demonstrated a 41% sensitivity and a 100% specificity for infection (PPV 100%, NPV 88%, accuracy 89%). Joint distension was 83% sensitive and 96% specific with a PPV of 83%, NPV of 96%, and accuracy of 94%. Thus, fluid collections in muscles and perimuscular fat had a 100% PPV, and absence of joint distention had a 96% NPV for infection. In the same study, periostitis was 100% specific but only 16% sensitive for infection. (PPV 100%, NPV 84%, accuracy 85%) [84]. A more recent study by Isern-Kebschull et al [85] confirmed that findings on


Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty noncontrast multidetector CT could differentiate delayed periprosthetic joint infection from aseptic loosening or granulomas. Intravenous (IV) contrast may be of help in defining abscess [23].


Imaging after Total Hip Arthroplasty PCAs. FDG-PET/CT Skull Base to Mid-Thigh Reported results for diagnosing periprosthetic hip infection have been inconsistent. In some investigations, the test has been both sensitive (81%-95%) and specific (89%-94%) for infection [82,86-90]. The results of other investigations; however, have been less satisfactory, with sensitivity and specificity ranging from 64% to 100% and 38% to 68% [91-93]. Delank et al [94] reported that although a negative FDG-PET excludes infection, a positive result could not accurately differentiate infection from aseptic inflammation. Kiran et al [92] performed preoperative FDG-PET/CT on 130 painful cemented hip arthroplasties and reported a sensitivity of 95% and a specificity of 38% for periprosthetic infection. In this investigation, the false-positive rate of FDG PET/CT compared with culture alone was 77%.


Imaging after Total Hip Arthroplasty PCAs. Comparisons of FDG-PET with conventional nuclear medicine studies have been contradictory. Some investigators have reported that FDG-PET is more accurate than bone scintigraphy and labeled leukocyte and marrow imaging, whereas other investigators have reported the opposite results [61,82,87,88,95,96].


Imaging after Total Hip Arthroplasty PCAs. Fluoride PET/CT Skull Base To Mid-Thigh Based on the available data, fluoride PET/CT does not appear to offer any advantages over FDG-PET/CT or 3- phase bone scintigraphy for diagnosing periprosthetic hip infection [97-100].


Imaging after Total Hip Arthroplasty PCAs. Image-Guided Aspiration Hip Although both false-positive and false-negative results may occur, joint aspiration with synovial fluid analysis remains probably the most useful test for confirming the presence or absence of infection and identifying the causative organism [101]. A meta-analysis by Carli et al [102] yielded a mean sensitivity of 68.6% and a specificity of 96.4% for joint aspiration culture. Hip aspiration can be performed using fluoroscopic, US, or CT guidance or without image guidance [103-105]. Contrast injection has been described for CT arthrography following joint aspiration [106].


Imaging after Total Hip Arthroplasty PCAs. Specific tests of retrieved synovial fluid such as alpha-defensin and polymerase chain reaction for bacteria and leukocyte esterase are beyond the scope of this review [107].


Imaging after Total Hip Arthroplasty PCAs. MRI Hip MRI can demonstrate soft tissue and bone features associated with periprosthetic infection, including inflammatory synovitis that may have a lamellated appearance [108], soft tissue edema, lymphadenopathy, fluid collections, bone marrow edema, and periosteal reaction [72,109-112].


Imaging after Total Hip Arthroplasty PCAs. IV contrast can be used to differentiate phlegmon from abscess and to define sinus tracts and communicating fluid collections [72]. However, IV contrast is generally not necessary to make the diagnosis of infection [72]. Evaluation of 19 patients suspected of having infection showed noncontrast MRI to be highly reproducible in the detection, localization, quantification, and characterization of fluid collections [113].


Imaging after Total Hip Arthroplasty PCAs. Galley et al [110] used optimized MRI sequences and found irregular soft tissue mass, soft tissue edema, bone destruction, and fistulas to be significant features of periprosthetic infection, with sensitivities of 47.4% to 100% and specificities of 73.1% to 100.0%. Albano et al [109] found lymph node assessment (of the affected compared to the unaffected hip) identified infected implants with high accuracies (up to 93.1%). Galley et al [110] found periosteal reaction, capsular edema, and intramuscular edema after THA at 1.5T MRI with MAR to have high accuracy in the evaluation of periprosthetic joint infection (86%-91% accuracy). Schwaiger et al [112] were able to distinguish patients with infection from those with loosening using MRI features. Soft tissue edema (sensitivity, 86.7% and specificity, >73.3%), abnormalities at both acetabular and femoral components (sensitivity/specificity, 66.7%/93.3%-100%), and enlarged lymph nodes (80%/86.7%) enabled this differentiation.


Imaging after Total Hip Arthroplasty PCAs. Radiographic Arthrography Hip There is no recent literature to support the current use of conventional arthrography of the hip in the evaluation of periprosthetic infection.


Imaging after Total Hip Arthroplasty PCAs. US Hip Detection of joint effusion, fluid collections, and sinus tracts is possible with US, and, therefore, this modality is helpful in identifying infection [47]. Some discrepancy regarding the reliability and threshold for detecting effusion on US has been noted [47,114]. van Holsbeeck et al [115] used US to evaluate 15 asymptomatic patients with total


Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty hip replacements and 33 patients who had pain in the hip after arthroplasty and radiologic findings consistent with component loosening (6 of whom had infection). All patients with intraarticular effusion and extraarticular extension had infection (100% specificity).


Imaging after Total Hip Arthroplasty PCAs. WBC Scan and Sulfur Colloid Scan Hip The role of combined leukocyte and marrow imaging for diagnosing periprosthetic hip infection has been studied by several investigators. Specificity has consistently been high, ranging from 88% to 100%. Sensitivity has been more variable, ranging from 33% to 100% [88,95,96,116,117].


Imaging after Total Hip Arthroplasty PCAs. Variant 5: Symptomatic hip arthroplasty patient, infection excluded. Additional imaging following radiographs. This variant includes wear, loosening, and osteolysis.


Imaging after Total Hip Arthroplasty PCAs. Bone Scan with SPECT or SPECT/CT Hip In 37 painful hip arthroplasties, the results of the bone scan with SPECT/CT were comparable to those of MRI for detecting polyethylene wear, periprosthetic fracture, infection, and aseptic loosening. MRI detected 21 soft tissue abnormalities, 14 tendon lesions (12 tendonopathies, 2 tears), 6 bursitis, and 1 pseudotumor. In contrast, bone scan with SPECT/CT found 1 soft tissue abnormality: iliopsoas tendinopathy, which also was identified on MRI [120].


Imaging after Total Hip Arthroplasty PCAs. CT Arthrography Hip Arthrography of the hip may be combined with CT [106]. However, most CT examinations of prostheses are not routinely performed with either IV or intraarticular contrast, particularly now that MAR algorithms for CT have been introduced [22,23].


Imaging after Total Hip Arthroplasty PCAs. CT Hip Liner wear: Liner wear may be detected on CT as thinning of the liner contour, development of a gap between a ceramic head and liner [22], shift of femoral head position within the acetabulum, and, in severe cases, metallic deposits in the soft tissues from contact between the femoral head and acetabular metal backing [122,123].


Imaging after Total Hip Arthroplasty PCAs. Loosening: Gillet et al [124] compared radiographs and CT with MAR (CT-MAR) for the diagnosis of component loosening. The sensitivity of CT for acetabular or femoral loosening was higher than for radiographs (33.3% and 51.5% for 2 readers for radiographs and 84.85 % for CT). The specificity of both radiographic and CT examinations was high and similar (96.9% and 100% for 2 readers for radiographs and 96.9% and 95.4% for CT). An advantage of CT is its ability to define the amount of the acetabular ingrowth surface that is in contact with bone [22].


Imaging after Total Hip Arthroplasty PCAs. Osteolysis: Osteolysis due to wear typically results in expansile well-defined lucent lesions. Helical CT with metal- artifact reduction is more sensitive than radiographs for identifying and quantifying osteolysis after THA [125]. Walde et al [126] confirmed CT to be more sensitive than radiographs for periacetabular lesion detection in a cadaver model (74.7% sensitivity for CT, 51.7% sensitivity for radiographs). Comparison of CT and MRI


Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty demonstrated that for lesions of all sizes, CT was less sensitive than MRI (CT, 74.7% sensitive and MRI, 95.4% sensitive) [126].


Imaging after Total Hip Arthroplasty PCAs. Most CT examinations of prostheses are not routinely performed with either IV or intraarticular contrast, particularly now that MAR algorithms for CT have been introduced [22,23].


Imaging after Total Hip Arthroplasty PCAs. Fluoride PET/CT Skull Base To Mid-Thigh Although most investigations have focused on the ability of fluoride PET/CT to differentiate between aseptic loosening and periprosthetic infection, normal asymptomatic controls were included in several of them. Kobayashi et al [98] reported that increased periprosthetic uptake was present in all cases of loosening and infection but in only 1 (3.7%) of 27 controls. Kumar et al [99] reported that 10 of 12 (83.3%) asymptomatic hip prostheses demonstrated no periprosthetic uptake, whereas periprosthetic uptake was present around all 28 aseptically loosened and all 16 infected devices. Choe at al [97] reported that 3 of 17 (17.6%) control hip prostheses demonstrated minor periprosthetic uptake and the mean SUVmax (4) was significantly less than that of aseptic loosening (7) and infection (11); P < .01 and P < .001, respectively.


Imaging after Total Hip Arthroplasty PCAs. Image-Guided Anesthetic Injection of Hip Intraarticular anesthetic has been used to evaluate painful THAs, primarily to differentiate referred pain (especially from the spine) from pain originating in the hip [127]. Significant pain relief after intraarticular anesthetic injection suggests an intraarticular cause [128,129]. Lack of improvement is thought to be unhelpful and warrants follow-up [129,130].


Imaging after Total Hip Arthroplasty PCAs. MRI Hip Wear: MRI is thought to be the most helpful tool for assessing the severity of intracapsular wear-induced synovitis [131]. On MRI, polyethylene wear-induced synovitis appears as low to intermediate signal intensity material that may distend the joint and extend into adjacent bursae [18].


Imaging after Total Hip Arthroplasty PCAs. Loosening: Burge et al [132] compared MRI with MAR techniques to radiographs with findings assessed at revision surgery. MRI was shown to be more sensitive than radiography for assessment of component loosening. For acetabular component loosening, MRI showed a sensitivity of 83% and a specificity of 98% compared with radiographs (sensitivity of 26% and specificity of 100%). For femoral component loosening, the sensitivity of MRI was 75% and the specificity 100%, whereas radiographs showed a sensitivity of 20% and a specificity of 100%. Backer et al [120] evaluated MRI and SPECT/CT for assessing loosening and found the sensitivity, specificity, PPV, and NPV of MRI were 86%, 88%, 60%, and 100% and of SPECT/CT were 93%, 97%, 90%, and 100%, respectively.


Imaging after Total Hip Arthroplasty PCAs. Osteolysis: There is some discrepancy in the literature regarding whether CT or MRI is the optimal study for detecting osteolysis. This may be related to technical factors. Potter et al [133] compared MRI appearances and surgical findings in 15 hips. In all operated cases, osteolysis found on MRI was confirmed at surgery. Walde et al [126] evaluated CT and MRI for the detection of osteolytic lesions in a cadaver model. For lesions of all sizes, CT was 74.7% sensitive and MRI was 95.4% sensitive. The sensitivity of radiographs was only 51.7%.


Imaging after Total Hip Arthroplasty PCAs. However, Robinson et al [134] demonstrated a reduced sensitivity (27%) and specificity (1%) of MARS-MRI in comparison with CT-MAR for detecting osteolysis associated with painful MoM hip prostheses.


Imaging after Total Hip Arthroplasty PCAs. There is insufficient literature documenting an additional benefit of MRI with IV contrast, relative to noncontrast MRI, in this population.


Imaging after Total Hip Arthroplasty PCAs. Radiographic Arthrography Hip Loosening: There is no recent relevant literature regarding the use of arthrography of the hip in the evaluation of component loosening. Older studies had suggested a selective role for arthrography for further analysis when there was hip pain and a question of loosening and negative or equivocal radiographs [135,136]. However, this examination appears to be little used currently.


Imaging after Total Hip Arthroplasty PCAs. Variant 6: Evaluation of symptomatic hip arthroplasty patient with metal-on-metal prosthesis or findings suggesting trunnionosis. Question of adverse reaction to metal debris. Additional imaging following radiographs. Changes due to ARMD may occur months or years after surgery and can be symptomatic or asymptomatic [7,137]. The results of revision surgery may be poor, and early identification of soft tissue changes of ARMD is thought to be important to improve outcome [7,138]. Investigators have sought to identify clinical, laboratory (eg, cobalt and


Imaging After Total Hip Arthroplasty

Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty


Imaging after Total Hip Arthroplasty PCAs. chrome ion levels in the blood), and patient features that could identify patients with or likely to develop ARMD so that revision or close follow-up could be performed. These are outside the scope of this document. Imaging remains a critical resource although its optimal utilization is still being clarified.


Imaging after Total Hip Arthroplasty PCAs. CT Hip Overall, CT is less able than MRI to detect changes associated with ARMD. Noncontrast CT may be considered following other imaging modalities to assess osteolysis.


Imaging after Total Hip Arthroplasty PCAs. Robinson et al [134] found a sensitivity of 44% for CT in comparison with MARS-MRI for ARMD pseudotumor detection in patients with unexplained painful MoM prostheses. Also, the detected pseudotumors could not be classified as to structure using CT. Thus, the authors concluded that CT would not be a suitable alternative for MARS-MRI and another study such as US may be considered.


Imaging after Total Hip Arthroplasty PCAs. CT is also less able to detect muscle atrophy. In comparison with MARS-MRI, CT demonstrated a high rate of false-negative examinations for identifying muscle atrophy (sensitivity of 81%, specificity of 37%) [134].


Imaging after Total Hip Arthroplasty PCAs. Although, Walde et al [126] demonstrated in a cadaver model that MRI could detect osteolysis with greater sensitivity than CT. Robinson et al [134] demonstrated a reduced sensitivity (27%) and specificity (1%) of MARS- MRI in comparison with CT-MAR for detecting osteolysis associated with painful MoM hip prostheses.


Imaging after Total Hip Arthroplasty PCAs. MRI Hip MARS-MRI has been used as a reference standard for imaging of the soft tissues around prosthetic hips [134,139].


Imaging after Total Hip Arthroplasty PCAs. ARMD Pseudotumors: MRI allows demonstration, localization, measurement, follow-up, determination of solid or cystic composition, and classification of pseudotumors associated with ARMD [36]. Invasion of adjacent soft tissues, muscle atrophy, and tendon avulsions can also be assessed [36,40,131].


Imaging after Total Hip Arthroplasty PCAs. Mahajan et al [140] found a difference in the appearance of pseudotumors depending on the site of corrosion. The MoP group demonstrated the highest proportion of thick-walled cystic masses (56.7% in head-neck taper corrosion MoP and 46.5% in dual taper corrosion MoP versus 28.7% in MoM), whereas the MoM group had the highest proportion of thin-walled cystic masses [140]. Weber et al [141] found no significant difference between the MRI appearances of symptomatic and asymptomatic MoP ARMD.


Imaging after Total Hip Arthroplasty PCAs. Several studies have compared MARS-MRI with surgically proven ARMD pseudotumors. Sensitivity ranged from 71% to 93.9%. Specificity ranged from 42.9% to 87% [39,40,66].


Imaging after Total Hip Arthroplasty PCAs. Lainiala et al [39] found a higher sensitivity for detecting ARMD pseudotumors for studies performed within 3 months before revision surgery (88% sensitivity, 78% specificity), and a lower sensitivity for studies obtained >1 year before revision surgery (sensitivity 29%, specificity 97%). It was suggested that studies >1 year not be used for clinical decision making or planning revision surgery.


Imaging after Total Hip Arthroplasty PCAs. Combined US and MARS-MRI studies: Comparison to surgical results suggests combining US and MARS-MRI improves accuracy. Small numbers of lesions detected on US are not visible on MRI, and some lesions seen on MRI are not apparent on US [41,52].


Imaging after Total Hip Arthroplasty PCAs. Wear: MRI is the most accurate imaging method for assessing wear induced synovitis [131]. Synovial characteristics may reflect the implant type and wear severity [9,142].


Imaging after Total Hip Arthroplasty PCAs. Osteolysis: As noted above, there are conflicting reports regarding the optimal study for detecting osteolysis. Walde et al [126] demonstrated in a cadaver model that MRI could detect osteolysis with greater sensitivity than CT. The sensitivity for detecting lesions was 51.7% for radiography, 74.7% for CT, and 95.4% for MRI. CT was more accurate; however, than MRI for measuring lesion volume [126].


Imaging after Total Hip Arthroplasty PCAs. Robinson et al [134]; however, demonstrated a reduced sensitivity (27%) and specificity (1%) of MARS-MRI in comparison with CT-MAR for detecting osteolysis associated with painful MoM hip prostheses. Morozov et al [143] evaluated 20 symptomatic patients with MoP prostheses with corrosion at the head-neck taper. Comparison of MRI and surgical findings found MRI to have limited sensitivity for either acetabular (11.1% sensitivity) or femoral (33.3% sensitivity) osteolysis [143].


Imaging after Total Hip Arthroplasty PCAs. There is insufficient literature documenting the additional benefit of MRI with IV contrast, relative to noncontrast MRI, in this population.


Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty US Hip US can be used to detect ARMD pseudotumors (solid or cystic) and other findings seen with ARMD such as joint effusions, bursal collections, capsular and bursal thickening, and synovitis [36]. Kwon et al [52] found that US was valid and useful for detecting interval changes in lesion size and grade in comparison with MARS-MRI.


Imaging after Total Hip Arthroplasty PCAs. A summary of studies comparing US to MARS-MRI as the reference standard for detecting ARMD shows sensitivities for US of 69% to 100% and specificities of 83% to 96% [36].


Imaging after Total Hip Arthroplasty PCAs. In a series of 82 hips (82 patients) undergoing revision of MoM prostheses, Lainiala et al [51] found a sensitivity of 83% and specificity of 92% for US examination of pseudotumors in the trochanteric region and a sensitivity of 79% and specificity of 94% for identifying pseudotumors in the iliopsoas region.


Imaging after Total Hip Arthroplasty PCAs. Matharu et al [66] studied a series of 40 MoM hip resurfacing arthroplasties in 39 patients undergoing revision surgery who had preoperative imaging with both US and MARS-MRI. Comparison with operatively identified pseudotumors showed US to have a sensitivity of 90.9% and a specificity of 42.9% compared with an MRI sensitivity of 93.9% and specificity of 57.1%. The PPV was similar (88.2% US, 91.2% MRI), but the NPV was higher for MRI (66.7% on MRI, 50.0% for US) [66].


Imaging after Total Hip Arthroplasty PCAs. Combined US and MARS-MRI studies: Comparison to surgical results suggests combined US and MARS-MRI improves accuracy. Small numbers of lesions detected on US are not visible on MRI, and some lesions seen on MRI are not apparent on US [41,52].


Imaging after Total Hip Arthroplasty PCAs. Variant 7: Hip arthroplasty patient with trochanteric pain. Suspect abductor injury, or trochanteric bursitis, or other soft tissue abnormality. Additional imaging following radiographs. Postoperative greater trochanter pain may be due to greater trochanteric bursitis, or other etiologies such as gluteus minimus or medius tendinitis, or tears or avulsion [73]. Trochanteric bursitis is reported to occur in up to 17% of hips after THA and may be related to the surgical approach [144,145].


Imaging after Total Hip Arthroplasty PCAs. CT Hip CT is less optimal than MRI for assessing soft tissues [22]. Fractures and fluid collections can be identified on CT.


Imaging after Total Hip Arthroplasty PCAs. Image-Guided Anesthetic +/- Corticosteroid Injection Hip Joint or Surrounding Structures If trochanteric bursitis is thought to be a source of pain, Robbins et al [144] suggest the bursa may be injected with either lidocaine alone as a diagnostic test, or in combination with a corticosteroid as a therapeutic measure.


Imaging after Total Hip Arthroplasty PCAs. MRI Hip MRI can be used to assess peritrochanteric structures including the gluteus minimus and medius muscles, abductor tendons, and the trochanteric bursa [146,147]. There is no relevant literature documenting the additional benefit of MRI with IV contrast, relative to noncontrast MRI, in this population.


Imaging after Total Hip Arthroplasty PCAs. Pfirrmann et al [147] compared the MRI findings about the greater trochanter in 25 patients after primary THA without pain and 39 patients with trochanteric pain and abductor weakness. Although several abnormalities were seen in both symptomatic and asymptomatic groups, defects of the abductor tendons and fatty atrophy of the gluteus medius muscle and the posterior part of the gluteus minimus muscle were uncommon in asymptomatic patients. Comparison of MRI findings with findings at surgical revision in 14 patients confirmed all MRI tendon findings.


Imaging after Total Hip Arthroplasty PCAs. Joint distension and decompression of synovitis into the greater trochanteric bursa and fluid undermining the hip abductors can be assessed on MARS-MRI [72]. Weber et al [141] noted that extracapsular disease associated with ARMD could be misinterpreted as trochanteric bursitis.


Imaging after Total Hip Arthroplasty PCAs. Radiographic Arthrography Hip Weakness or detachment of the abductor muscles may occur after THA using an anterolateral approach [148]. Avulsion of the reattached gluteus medius can provide a communication between the hip joint and the trochanteric bursa that can be documented on arthrography [148]. Ylinen et al [148] found that all 14 patients with this communication had abductor avulsion at revision surgery. A negative study did not exclude disruption (sensitivity 60.1%, specificity 100%). The failure of contrast to extend to the trochanteric region in these cases was attributed to blocking of its flow by a fibrous capsule.


Imaging after Total Hip Arthroplasty PCAs. US Hip US can identify tendinopathy, partial tear, and complete tears/avulsion of the gluteus medius tendon in nonsurgical and postsurgical patients [47,73]. Bancroft and Blankenbaker [149] noted the postsurgical appearance of repaired


Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty gluteal tendons will vary depending on the type of procedure performed, but continuity of the reattached tendon should be present and can be demonstrated on US. Garcia et al [150] used US to evaluate the abductor tendons after THA using a lateral transgluteal approach. They found abductor tendon tears in half of patients with positive Trendelenburg signs (4 of 8) and in 3 of 26 patients with negative Trendelenburg tests. No comparison to surgical revision was available.


Imaging after Total Hip Arthroplasty PCAs. US can detect trochanteric bursitis [47]. According to Douis et al [47], differentiation between bursitis and gluteus medius tendinosis may be difficult, and the 2 may coexist.


Imaging after Total Hip Arthroplasty 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.


Imaging after Total Hip Arthroplasty PCAs. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Imaging After Total Hip Arthroplasty

Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty


Newly Diagnosed Palpable Scrotal Abnormality. Introduction/Background Palpable scrotal abnormalities are caused by a variety of disorders, ranging from indolent benign conditions to aggressive tumors as well as infectious and vascular processes, often requiring emergent surgical intervention [1- 3]. In these patients, the diagnostic workup typically begins with a complete clinical history and physical examination, including analysis of risk factors, often followed by imaging [4,5].


Newly Diagnosed Palpable Scrotal Abnormality. Germ cell testicular tumors (GCTT) are the most frequently diagnosed cancer in young men and constitute approximately 95% of all testicular tumors [6]. It is estimated that 1 in 250 men will develop GCTT during their lifetime, most often between 20 to 34 years of age, representing 0.5% of all new malignancies [6]. GCTT histologically include seminoma and nonseminoma (52% and 48%, respectively) or mixed tumors [7].


Newly Diagnosed Palpable Scrotal Abnormality. Most patients with GCTT are diagnosed quite early and present with stage I disease, when the tumor is confined to the testicle; in these patients, inguinal orchiectomy is the first recommended maneuver that has both diagnostic and therapeutic aims [13]. Close clinical and imaging surveillance with or without short-course adjuvant chemotherapy are accepted alternatives for patients with stage I disease [6]. In patients with more advanced disease presenting with extratesticular tumor, several courses of chemotherapy followed by the judicious surgical removal of residual tumor is commonly used. High-risk patients and those with relapsing or refractory disease are referred to specialized tertiary centers for advanced high-dose chemotherapy plus autologous hematopoietic support [8].


Newly Diagnosed Palpable Scrotal Abnormality. Special Imaging Considerations Contrast-enhanced ultrasound (CEUS) and US shear-wave elastography (SWE) are gaining clinical acceptance as useful additions to first-line US examinations of the scrotum in patients with newly diagnosed palpable scrotal abnormality.


Newly Diagnosed Palpable Scrotal Abnormality. aThomas Jefferson University Hospital, Philadelphia, Pennsylvania. bPanel Chair, Northwestern University, Chicago, Illinois. cPanel Vice-Chair, UT Southwestern Medical Center, Dallas, Texas. dUT Southwestern Medical Center, Dallas, Texas. eUniversity of Cincinnati, Cincinnati, Ohio. fThe University of Texas MD Anderson Cancer Center, Houston, Texas. gDuke University Medical Center, Durham, North Carolina. hRoswell Park Cancer Institute, Jacobs School of Medicine and Biomedical Science, Buffalo, New York. iThomas Jefferson University Hospital, Philadelphia, Pennsylvania, Primary care physician. jJohns Hopkins Hospital, Baltimore, Maryland; American Urological Association. kCleveland Clinic, Cleveland, Ohio. lUniversity of Alabama at Birmingham, Birmingham, Alabama. mNew York University, New York, New York. nThe Ohio State University Wexner Medical Center, Columbus, Ohio. oSpecialty Chair, University of Alabama at Birmingham, Birmingham, Alabama.


Newly Diagnosed Palpable Scrotal Abnormality. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization.


Newly Diagnosed Palpable Scrotal Abnormality. Reprint requests to: publications@acr.org


Newly Diagnosed Palpable Scrotal Abnormality. OR Discussion of Procedures by Variant Variant 1: Newly diagnosed palpable scrotal abnormality. History of trauma or infection. Initial imaging. CT Abdomen and Pelvis CT of the abdomen and pelvis is not routinely used as an initial imaging modality for the evaluation of newly diagnosed palpable scrotal abnormality in patients with a history of trauma or infection. There is no relevant literature regarding the use of CT of the abdomen and pelvis in these patients.


Newly Diagnosed Palpable Scrotal Abnormality. CT Pelvis CT of the pelvis is not routinely used as an initial imaging modality for the evaluation of newly diagnosed palpable scrotal abnormality in patients with a history of trauma or infection. There is no relevant literature regarding the use of CT of the pelvis in these patients.


Newly Diagnosed Palpable Scrotal Abnormality. MRI Abdomen and Pelvis MRI of the abdomen and pelvis is not routinely used as an initial imaging modality for the evaluation of newly diagnosed palpable scrotal abnormality in patients with a history of trauma or infection. There is no relevant literature regarding the use of MRI of the abdomen and pelvis in these patients.


Newly Diagnosed Palpable Scrotal Abnormality. MRI Pelvis (Scrotum) MRI of the pelvis is not routinely used as an initial imaging modality for the evaluation of newly diagnosed palpable scrotal abnormality in patients with a history of trauma or infection but may be used as a problem-solving tool when findings are not clear on US. There is no relevant literature regarding the use of MRI of the pelvis in these patients.


Newly Diagnosed Palpable Scrotal Abnormality. Nuclear Medicine Scan Scrotum Nuclear scan of the scrotum is not routinely used as an initial imaging modality for the evaluation of newly diagnosed palpable scrotal abnormality in patients with a history of trauma or infection. There is no relevant literature regarding the use of nuclear scans of the scrotum in these patients.


Newly Diagnosed Palpable Scrotal Abnormality. Newly Diagnosed Palpable Scrotal Abnormality US Duplex Doppler Scrotum The combination of grayscale and color-power Doppler US can significantly improve the specificity of B-mode US in scrotal lesion characterization [1,32]. It is very useful in diagnosis of focal inflammatory processes, such as epididymitis and testicular abscess, that can present with palpable scrotal masses in some patients [33]. Nevertheless, duplex US does not allow a definitive differentiation of malignancies from a variety of benign conditions, such as orchitis, dermoid cyst, granuloma, focal fibrosis, adrenal rest, and papillary cystadenoma. In fact, those lesions can mimic cancer, and, as a consequence, the specificity of a duplex US examination of the scrotum is lower than its sensitivity [34]. Other potential diagnoses that may be demonstrated on US include testicular hematoma, rupture (particularly in patients with a history of trauma), infarct, torsion, intratesticular varicocele, and arteriovenous malformations or angiomatosis [35].


Newly Diagnosed Palpable Scrotal Abnormality. US Scrotum A variety of infectious and traumatic processes can be accurately depicted and characterized on grayscale US [36]. Sonographically, the involved testicle may have heterogenous, hypoechoic echotexture. Additional findings in testicular trauma may include contour abnormality, disruption of the tunica albuginea, or direct visualization of a fracture line. Sonographic appearance of intratesticular hematoma depends on the time from trauma, with the hyperacute or acute hematoma appearing as a heterogeneous or isoechoic area relative to surrounding testicular parenchyma, whereas chronic hematomas are smaller in size and relatively hypoechoic to anechoic. However, scrotal US without Doppler imaging may not be able to differentiate a hematoma from a mass or evaluate for inflammation.


Newly Diagnosed Palpable Scrotal Abnormality. Variant 2: Newly diagnosed palpable scrotal abnormality. No history of trauma or infection. Initial imaging. CT Abdomen and Pelvis CT of the abdomen and pelvis is not routinely used as an initial imaging modality for the evaluation of newly diagnosed palpable scrotal abnormality in patients without history of trauma or infection. There is no relevant literature regarding the use of CT of the abdomen and pelvis in these patients.


Newly Diagnosed Palpable Scrotal Abnormality. CT Pelvis CT of the pelvis is not routinely used as an initial imaging modality for the evaluation of newly diagnosed palpable scrotal abnormality in patients without a history of trauma or infection. There is no relevant literature regarding the use of CT of the pelvis in these patients.


Newly Diagnosed Palpable Scrotal Abnormality. MRI Abdomen and Pelvis MRI of the abdomen and pelvis is not routinely used as an initial imaging modality for the evaluation of newly diagnosed palpable scrotal abnormality in patients without a history of trauma or infection. There is no relevant literature regarding the use of MRI of the abdomen and pelvis in these patients.


Newly Diagnosed Palpable Scrotal Abnormality. MRI Pelvis (Scrotum) MRI is not routinely used as the initial examination to evaluate scrotal pathology given its uncertain clinical utility when used in addition to standard US [37,38]. In select cases, it could be help distinguish between an intratesticular and extratesticular mass when this cannot be confirmed clinically or with US [8]. MRI may aid in the diagnosis of a primary testicular mass, mostly focusing on differential diagnosis between benign and malignant testicular masses [39]. Quantitative enhancement patterns may be useful to distinguish testicular seminoma from Leydig cell tumors in direct comparison, but it is uncertain how they would perform in a routine clinical practice [40].


Newly Diagnosed Palpable Scrotal Abnormality. Nuclear Medicine Scan Scrotum Nuclear scan of the scrotum is not routinely used as an initial imaging modality for the evaluation of newly diagnosed palpable scrotal abnormality in patients without a history of trauma or infection. There is no relevant literature regarding the use of nuclear scans of the scrotum in these patients.


Newly Diagnosed Palpable Scrotal Abnormality. US Duplex Doppler Scrotum The combination of grayscale and color-power Doppler US can significantly improve the specificity of B-mode US in scrotal lesion characterization [1,32]. US duplex may be able to differentiate a solid mass from a mass-like hematoma. which will be avascular (can occur without trauma). Nevertheless, duplex US does not allow a definitive differentiation of malignancies from a variety of benign conditions, such as orchitis, dermoid cyst, granuloma, focal fibrosis, adrenal rest, and papillary cystadenoma. In fact, those lesions can mimic cancer, and, as a consequence, the specificity of duplex US examination of the scrotum is lower than its sensitivity [34].


Newly Diagnosed Palpable Scrotal Abnormality. 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.


Newly Diagnosed Palpable Scrotal Abnormality. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Introduction/Background Gestational trophoblastic disease (GTD), or abnormal proliferation of placental trophoblastic tissue, is a rare complication of pregnancy. There is considerable variation in the worldwide distribution of GTD, with the highest frequencies reported in Asia and the Middle East and lower rates on the order of 1 per 1,000 pregnancies in Europe and North America [1,2]. Extremes of maternal age and personal history of GTD are known risk factors [1-3].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. 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.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Reprint requests to: publications@acr.org


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Gestational Trophoblastic Disease


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. On the whole, women with GTD have a favorable prognosis for cure with early adequate treatment, despite the presence of metastatic disease in some patients. Patients with benign but premalignant lesions are managed with uterine evacuation and enrolled in postoperative hCG surveillance [16]. Hysterectomy in patients not opting to preserve fertility does not eradicate risk of postmolar GTN [16-19]. If malignant GTN other than ETT or PSTT is suspected or has been established, further evaluation for potential metastatic lesions is initiated, clinical risk factors determined, and patients stratified into low- or high-risk groups based on the modified World Health Organization (WHO) prognostic scoring system as adapted by and combined with the international Federation of Gynecology and Obstetrics (FIGO) anatomic staging system [2,20]. This combines anatomic staging with assessment of prognostic factors: patient age, type of antecedent pregnancy, interval from gestational event to chemotherapy, hCG concentration, number and site of metastases, largest tumor mass, and previous chemotherapy. Points are assigned for each variable to determine risk of resistance to single-agent chemotherapy. Scores exceeding 6 predict high-risk disease refractory to monochemotherapy, with patients maintaining good prognosis if managed with intensive combination chemotherapy [10]. Patients with brain metastases are automatically assigned a high-risk disease status, regardless of score [12]. Adjuvant surgical and/or radiation therapy can be added selectively to decrease disease burden and remove resistant lesions [21-23]. ETT and PSTT, biologically distinct tumors that are relatively refractory to chemotherapy and grow more slowly with local lymphatic rather than hematogenous metastases, are staged anatomically and primarily treated surgically [24].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Special Imaging Considerations A healthy twin live fetus may coexist alongside a partial or complete molar pregnancy. A rare phenomenon, this has been estimated to occur in 1 in 20,000 to 100,000 pregnancies [10]. The management of this entity is controversial as there is some concern that these patients may be more prone to developing GTN among other potential serious complications, such as pre-eclampsia, thyrotoxicosis, hemorrhage, trophoblastic embolism, and fetal demise [25,26]. Evidence from a series of 77 cases, however, suggests that approximately 40% of these patients may successfully deliver a healthy baby without increased incidence of malignant transformation [10,27]. Because this scenario is exceedingly rare, there is little high-quality evidence to support imaging guidelines.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. US Pelvis Transvaginal Transvaginal US is the accepted standard in the evaluation of early pregnancy and suspected complications. Although <50% of hydatidiform moles were prospectively identified on US in studies published >10 years ago [21,22], a more recent study reported improved sensitivity using contemporary US equipment with 86% of complete moles and 41% of partial moles diagnosed prospectively [23]. Reported sensitivity of US detection is higher for complete mole, with its more pronounced hydropic changes of chorionic villi and absence of a gestational sac, than for partial mole [9,28]. Features suspicious for partial mole include an enlarged placenta or cystic changes within the decidual reaction in association with either an empty sac (>20 mm in diameter) or a delayed miscarriage (fetal pole with crown-rump length >6 mm but no cardiac activity) [22]. Differential diagnosis in partial molar pregnancy may include missed abortion [29] and retained products of conception. There is no substantial evidence to support a role for grayscale US features in risk stratification for future development of GTN [30,31]. Enlarged ovaries with multiple theca lutein cysts may be a helpful secondary finding in suspected GTD but are noted in <50% of patients [29,30].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Gestational Trophoblastic Disease US Pelvis Transabdominal Transvaginal US has superior sensitivity and specificity in the diagnosis of uterine masses when compared with transabdominal US, although given the rarity of GTD, literature comparing both modalities is lacking [32].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. US Duplex Doppler Pelvis There is some support for a role for Doppler US in the initial diagnosis and postevacuation follow-up of patients with GTD. A lower uterine artery resistive index before molar evacuation is associated with the development of trophoblastic tumors, a potentially useful means to prospectively recognize patients who are at high risk for progression and warrant closer follow-up [33,34]. In a prospective analysis of 246 women with complete mole, Doppler pulsatility index showed potential as a predictor of subsequent development of GTN [35]. In a retrospective analysis of 189 patients with hydatidiform mole, US evidence of nodules and hypervascularization within the myometrium or endometrium 3 weeks following initial molar evacuation had a high specificity (95.5%) but low sensitivity (53.9%) for later development of GTN [33,34]. Doppler US can also confirm the absence of vascular flow within a mass, a useful technique in patients with GTD where clot or blood products may simulate solid tissue.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. CT Head If physical examination and chest radiographs are normal in a patient with GTD, metastases to other sites are unlikely, and further imaging investigation is not indicated [37,43].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. CT Abdomen and Pelvis If physical examination and chest radiographs are normal in a patient with GTD, metastases to other sites are unlikely, and further imaging investigation is not indicated [37,43].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Gestational Trophoblastic Disease MRI Head If physical examination and chest radiographs are normal in a patient with GTD, metastases to other sites are unlikely, and further imaging investigation is not indicated [37,43].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. MRI Pelvis To our knowledge, there is no evidence to support the routine use of MRI for initial evaluation of known or suspected GTD. Evaluation of MRI in patients with hydatidiform mole is limited to small series and cases reports [44-46]. Diffusion-weighted imaging has been evaluated as a potential predictor of subsequent GTN development in a small retrospective study and was not found to be useful [46].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. FDG-PET/CT Skull Base to Mid-Thigh To our knowledge, there is no evidence to support the routine use of fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT for initial evaluation of known or suspected GTD. Preliminary limited data suggest a potential role for FDG-PET/CT in the identification of patients who are likely to develop GTN following initial treatment for molar pregnancy [47]. A significant difference in the standardized uptake value-max (SUVmax) of pre- evacuation intrauterine molar tissue in patients who achieved normalization of hCG versus those who progressed to GTN following dilatation and curettage was observed in this single retrospective study of 11 patients [47].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. US Pelvis Transabdominal Transvaginal US has superior sensitivity and specificity in the diagnosis of uterine masses when compared with transabdominal US, although, given the rarity of GTN, literature comparing both modalities is lacking [32].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Radiography Chest The lungs are the most common site of metastasis in GTN [7,36,60]. Chest radiographs are the primary imaging method recommended by FIGO to detect and count lung metastases for purposes of risk assessment in patients with GTN. However, approximately 30% to 40% of patients assumed to have nonmetastatic disease by radiographs may have CT evidence of micrometastases [20,38,39]. The emphasis on radiographs may in part reflect the global scope of FIGO, which provides recommendations that must apply to both industrialized countries and underresourced medical care environments. CT chest may be preferred where available because of its greater sensitivity, although controversy persists regarding the prognostic significance of tiny nodules detected by CT, as discussed below. However, the statement that chest radiographs are used for counting the number of metastases, not CT chest, was also rated as highly appropriate by a panel of 45 experts from 16 countries in association with the EOTTD [6].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. CT Chest The lungs are the most common site of metastasis in GTN [7,36,60]. Approximately 30% to 40% of patients assumed to have nonmetastatic disease by radiographs may have CT evidence of micrometastases [20,38-40]. However, the clinical importance of these tiny lesions remains controversial as there is no definitive evidence of impact on long-term survival [38,41]. Assessment of the literature is complicated by the fact that suspected pulmonary micrometastases from GTN are often not confirmed histologically because they typically regress completely with treatment and biopsy is not recommended [40]. Despite some disagreement in the literature regarding modality choice to diagnose lung metastases, patients with suspected or confirmed GTN are often initially evaluated with chest CT at many institutions. Although micrometastases are not thought to impact survival, their presence increases the likelihood of other areas of metastatic involvement and should trigger other anatomic imaging [19]. Otherwise stated, the negative predictive value of chest CT in patients with GTN is high and of substantial clinical value because hepatic or brain metastases are very unlikely in the absence of pulmonary metastases [37]. Because the lungs are the most common site of GTN metastases, the use of IV contrast is not necessary to improve lesion detection.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. The use of low-dose CT as a means to assess pulmonary metastases in patients with GTN was evaluated in a small study comparing standard- and low-dose CT examinations [42]. Although the number of nodules detected on the low-dose CT protocols was significantly less than the number identified on standard-dose CT examinations, the disease staging and risk score of the patients were not impacted.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. The EOTTD expressed a strong preference for MRI over CT for neurologic staging in a study that assessed the level of agreement among an expert panel regarding the management of patients with GTD [6]. However, in the setting of urgent neurologic findings that are due to space-occupying or hemorrhagic metastases, the ACR


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. MRI Pelvis In women with GTN, pelvic MRI can delineate uterine and vaginal masses, and may provide useful detail regarding the depth of local invasion [44,46,61]. Local staging information is particularly relevant in patients with ETT or PSTT because these tumors may have extensive uterine involvement [14,15,52]. ETT and PSTT are both relatively chemoresistant, and surgical resection may have a primary role in therapy if the tumor is confined to the uterus. As such, MRI has the potential to provide important information for treatment planning. Local parametrial invasion, vaginal involvement, and pelvic extension are all better assessed with MRI than US [44]. Because the primary tumor and GTN metastases are typically vascular, IV contrast enhancement is useful to improve lesion detection. Vaginal gel may be useful to distend the vagina, optimizing the delineation of any masses or extension, if present. The majority of patients with postmolar GTN not treated with hysterectomy will have locally invasive disease [17].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Given the rare nature of ETT and PSTT, there are few consistent descriptions of imaging features, limited to small series and case reports [15,52,65]. MRI assessment of lymph node status is important to treatment planning in patients with PSTT and ETT, but other forms of GTN predominantly spread via hematogenous routes.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. FDG-PET/CT Skull Base to Mid-Thigh The role of FDG-PET/CT in the evaluation of patients with GTN is inconclusive and evolving given the uncommon nature of the disease. There is some evidence that FDG-PET/CT may be useful to precisely map tumor extent prior to chemotherapy, as well as to monitor tumor response and identify sites of persistent disease following therapy [66-69]. One systematic review included 19 papers totaling 81 cases of GTN, with FDG- PET/CT used in the initial staging in 59 of 81 patients and in the follow-up after initial chemotherapy in 22 of 81 patients [47]. The largest study included in this review (41 patients) showed concordance between FDG-PET or PET/CT and conventional studies that ranged from 81% to 91% with the highest discordance in chest CT, all false-negative [68]. Among all summarized data, FDG-PET or PET/CT studies facilitated localization of persistent or unusual sites of metabolically active disease, enabled distinction of false-positive lesions on conventional studies related to areas of necrotic or hemorrhagic tissue, and identified additional or occult lesions in a small number of patients. Small lesion size, paucity of FDG-avid cells, and poorly differentiated tumors may contribute to false-negative studies.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Variant 3: Surveillance of GTN, including refractory, relapsed, or quiescent GTN. GTN is highly chemosensitive and associated with excellent outcomes, but drug resistance and relapse can occur. This is more common in patients with high-volume disease at diagnosis or in those with inadequate initial therapy. Up to 12.5% of patients with high-risk disease will develop recurrence after initial remission [19].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Gestational Trophoblastic Disease


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. US Pelvis Transabdominal Transvaginal US has improved sensitivity and specificity in the diagnosis of uterine masses when compared with transabdominal US, although given the rarity of this disorder, series that compare both modalities in patients with GTN are lacking [32].


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. Radiography Chest Evaluation of lung metastases in patients with relapsed or refractory disease is better accomplished with chest CT because primary prognostic scoring is no longer an issue in this patient population.


Gestational Trophoblastic Disease

Gestational Trophoblastic Disease. CT Chest Because GTN metastases involve the lungs rather than the mediastinum, IV contrast enhancement is not necessary to improve lesion detection. Although radiographic evidence of tumor regression can lag behind a favorable biochemical response to treatment, thoracotomy with wedge resection of pulmonary lesions is sometimes performed in patients with persistent nodules. This is generally only indicated with isolated chemoresistant lesions in the absence of disease elsewhere [16,71]. Regardless, it remains the most common surgical procedure for extrauterine metastases [16,18,71].