Clinically Suspected Adnexal Mass No Acute Symptoms. The transvaginal component allows for detailed evaluation with the transabdominal component helpful for larger lesions that may be suboptimally seen transvaginally. US Pelvis Transvaginal The most useful modality for evaluation of adnexal masses includes transvaginal US combined with a transabdominal US approach. Variant 2: Adult patient assigned female at birth. Adnexal mass, likely benign, no acute symptoms. Premenopausal. Follow-up imaging. CT Pelvis With IV Contrast CT pelvis with IV contrast is usually not useful to follow likely or known benign adnexal masses. Because the roles of US and MRI are well established, there is little reason presently to obtain a CT for benign mass follow-up. CT Pelvis Without and With IV Contrast CT pelvis without and with IV contrast is usually not useful to follow likely or known benign adnexal masses. Because the roles of US and MRI are well established, there is little reason presently to obtain a CT for benign mass follow-up. CT Pelvis Without IV Contrast CT pelvis without IV contrast is usually not useful to follow likely or known benign adnexal masses. Because the roles of US and MRI are well established, there is little reason presently to obtain a CT for benign mass follow-up. Clinically Suspected Adnexal Mass FDG-PET/CT Skull Base to Mid-Thigh There is no role for the use of FDG-PET/CT in the follow-up of benign adnexal masses in premenopausal patients. MRI Pelvis Without and With IV Contrast Although MRI can accurately characterize these benign lesions, it is not the first-line modality [16,17]. If a known lesion requiring surveillance is unable to be followed via US, MRI would be the alternative imaging modality of choice for follow-up. Classically benign lesions such as simple cysts, endometriomas and dermoid, and extraovarian benign lesions have characteristic appearances on MRI and can be confidently diagnosed as almost certainly benign [17].


Clinically Suspected Adnexal Mass No Acute Symptoms. MRI Pelvis Without IV Contrast If MRI is being used for follow-up of a benign lesion, IV contrast is recommended to evaluate for any developing enhancing component. Contrast-enhanced MRI performs superiorly to both US and noncontrast MRI due to its ability to confirm the presence of internal enhancing soft tissue components [18]. A recent study evaluating the usefulness of noncontrast MRI in 350 lesions in a population with 15% malignancies and demonstrated a sensitivity of 85%, specificity of 96%, and accuracy of 94.2% to detect cancer [19]. Noncontrast MRI may be used in adnexal mass characterization when the use of IV contrast is precluded. US Duplex Doppler Pelvis Color or power Doppler should be included in the US examination of the pelvis. Color Duplex is used to evaluate vascularity of any developing solid component. US Pelvis Transabdominal Transabdominal US may be performed without transvaginal imaging when the transvaginal examination cannot be tolerated. The bladder should be full to provide the best acoustic window for evaluation. US Pelvis Transabdominal and US Pelvis Transvaginal US can accurately diagnose benign adnexal lesions including simple cysts, hemorrhagic cysts, endometriomas, and dermoids as well as extraovarian cystic lesions such as parovarian cysts, hydrosalpinx, and peritoneal inclusion cysts. Adnexal lesions that can be adequately assessed and characterized on US may be followed-up with US. The vast majority of simple cysts in premenopausal patients are functional cysts, which will wax and wane over time or resolve, with a small portion reflecting benign neoplasms. A large body of evidence including several large recent studies has shown that simple cysts, regardless of size and menopausal status, are not associated with an increased risk of cancer [35,47-49].


Clinically Suspected Adnexal Mass No Acute Symptoms. Invasive serous cystadenocarcinoma is now thought to primarily originate from solid precursors in the fallopian tube and serous tubal intraepithelial carcinoma, further supporting the benignity of simple ovarian cysts [50]. A recent consensus update to the SRU in 2019 regarding management of simple cysts reflects these findings with higher threshold for follow-up of simple cysts [42]. Namely, in premenopausal women, simple cysts, including paraovarian and paratubal cysts <5 cm, do not need to be followed. The rationale of follow- up for simple cysts >5 cm (and 7 cm for exceptionally well seen cysts) is based on a potential risk of mischaracterization of larger cysts and potential clinical value of size monitoring growth rates of larger cysts, which may reflect benign neoplasms and warrant clinical follow-up along with a very small predisposition for torsion or rupture [51]. Classic benign lesions include endometriomas, hemorrhagic cysts, and dermoids as well as benign extraovarian lesions such as paraovarian cysts, hydrosalpinx, and peritoneal inclusion cysts have characteristic appearances on US [23,34]. Hemorrhagic functional cysts will decrease or resolve on sonographic follow-up in 8 to 12 weeks versus nonfunctional cysts, which will persist. Endometriomas may change in appearance with age, losing the classic unilocular ground glass appearance with multilocular appearance and presence of nonvascular papillary or other solid components more common in older premenopausal women [52]. These changes can overlap with malignancy and endometriomas and require yearly follow-up due to a small risk of malignant transformation [53]. Sonographically diagnosed dermoids, if not excised, can be safely followed with yearly US with the risk of missing malignant degeneration quite low [54].


Clinically Suspected Adnexal Mass No Acute Symptoms. Clinically Suspected Adnexal Mass managed conservatively with 2-year follow-up was 0.3% to 0.4% for malignancy and 0.2% to 0.4% for acute complications such as torsion or cyst rupture [51]. Unilocular cysts, as a whole, in the premenopausal population similarly have a very low risk of malignancy. A recent meta-analysis by Parazzini et al [56] demonstrated that in 987 unilocular cysts removed surgically in premenopausal women, the risk of malignancy was 0.6%. Similar findings were found by Valentin et al [57], with a rate of malignancy of 0.5% in 981 surgically resected lesions. Surgical cohorts have a bias of increased risk of malignancy due to persistent cysts, and thus, this can be extrapolated into an even lower theoretical risk of malignancy in the general population. The most common benign solid adnexal mass is the uterine fibroid. Pedunculated lesions or broad ligament fibroids can often be mistaken for solid adnexal mass. Fibroids are present in up to 20% to 30% of reproductive age women, and the presence of bridging vessels can help identify uterine origin along with careful search for the ovaries [25]. US Pelvis Transvaginal The most useful modality for evaluation of adnexal masses includes transvaginal US combined with transabdominal US approach. Variant 3: Adult patient assigned female at birth. Adnexal mass, likely benign, no acute symptoms. Postmenopausal. Follow-up imaging. CT Pelvis With IV Contrast CT pelvis with IV contrast is usually not useful to follow likely or known benign adnexal masses. Because the roles of US and MRI are well established, there is little reason presently to obtain a CT for benign mass follow-up. CT Pelvis Without and With IV Contrast CT pelvis without and with IV contrast is usually not useful to follow likely or known benign adnexal masses. Because the roles of US and MRI are well established, there is little reason presently to obtain a CT for benign mass follow-up.


Clinically Suspected Adnexal Mass No Acute Symptoms. CT Pelvis Without IV Contrast CT pelvis without IV contrast is usually not useful to follow likely or known benign adnexal masses. Because the roles of US and MRI are well established, there is little reason presently to obtain a CT for benign mass follow-up. FDG-PET/CT Skull Base to Mid-Thigh There is no role for the use of FDG-PET/CT in the follow-up of benign adnexal masses in postmenopausal patients. MRI Pelvis Without and With IV Contrast Although MRI can accurately characterize these benign lesions, it is not the first-line imaging modality [16,17]. If a known lesion requiring surveillance is unable to be followed via US, MRI would be the alternative imaging modality of choice for follow-up. Classical benign lesions such as simple cysts, endometriomas and dermoid, and extraovarian benign lesions have characteristic appearances on MRI and can be confidently diagnosed as almost certainly benign [17]. MRI Pelvis Without IV Contrast If MRI is being used for follow-up of a benign lesion, IV contrast is recommended to evaluate for any developing enhancing component. Contrast-enhanced MRI performs superiorly to both US and noncontrast MRI due to its ability to confirm the presence of internal enhancing soft tissue components [18]. A recent study evaluating the usefulness of noncontrast MRI in 350 lesions in a population with 15% malignancies demonstrated a sensitivity of 85%, specificity of 96%, and accuracy of 94.2% to detect cancer [19]. Noncontrast MRI may be used in adnexal mass characterization when the use of IV contrast is precluded. US Duplex Doppler Pelvis Color or power Doppler should be included in the US examination of the pelvis. Color Duplex is used to evaluate vascularity of any developing solid component. US Pelvis Transabdominal Transabdominal US may be performed without transvaginal imaging when the transvaginal examination cannot be tolerated. The bladder should be full to provide the best acoustic window for evaluation.


Clinically Suspected Adnexal Mass No Acute Symptoms. Clinically Suspected Adnexal Mass US Pelvis Transabdominal and US Pelvis Transvaginal Likely benign adnexal lesions that can be adequately assessed and characterized on US may be followed sonographically. A large body of evidence including several large recent screening studies has shown that unilocular simple cysts, regardless of size and menopausal status, are not associated with an increased risk of cancer [35,47-49]. In a large series, approximately 13% to 14% of women over 50 to 55 years of age, respectively, had simple ovarian cysts, with 8% demonstrating new cysts and 32% with no cyst at 1-year follow-up, with a near nonexistent risk of malignancy [47]. A second recent study of 72,093 women, those with simple cysts, demonstrated an absolute 3- year risk of ovarian cancer, 0 to 0.5 cases per 10,000 women, not dissimilar to women with normal ovaries [47,49]. Invasive serous cystadenocarcinoma is now primarily thought to originate from solid precursors in the fallopian tube, serous tubal intraepithelial carcinoma, further supporting the benignity of simple ovarian cysts [50]. A recent consensus update to the SRU in 2019 regarding management of simple cysts reflects these findings with higher threshold for follow-up of simple cysts [42]. For postmenopausal patients, the SRU endorses follow-up of simple cysts >3 cm (and 5 cm for those that are exceptionally well seen) rather than the previous 1-cm threshold [42,58]. The rationale of follow-up for simple cysts is based on a potential risk of mischaracterization of larger cysts and potential clinical value of size monitoring growth rates of larger cysts, which may reflect benign neoplasms and warrant clinical follow-up. Unilocular cysts, as a whole, in the postmenopausal population similarly have a very low risk of malignancy.


Clinically Suspected Adnexal Mass No Acute Symptoms. In a surgical cohort of 3,511 masses, 217 of which were unilocular cysts in postmenopausal women, the rate of malignancy was 3%, with hemorrhagic contents more common in malignant unilocular lesions [57]. In a second study of 15,106 women with 3,259 unilocular cystic lesions, there were 10 cancers detected over a 6.3-year period, none of which developed from the isolated cystic lesion [59]. A more recent meta-analysis demonstrated that of 372 unilocular cysts removed surgically in postmenopausal women, the risk of malignancy was 3.2% [56]. US Pelvis Transvaginal The most useful modality for evaluation of adnexal masses includes transvaginal US combined with transabdominal US approach. Variant 4: Adult patient assigned female at birth. Adnexal mass, indeterminate on initial pelvic US, no acute symptoms. Premenopausal or postmenopausal. Next imaging study for characterization. Up to 22% to 24% of adnexal masses remain indeterminate after US evaluation [61,62]. No single definition exists for these indeterminate lesions. Some examples include multilocular cysts, or lesions with avascular or low level vascular internal solid components. In a multicenter prospective study of 303 indeterminate adnexal cysts, the incidence of malignancy was 3.6% [61]. In a second multicenter prospective study of 697 women, the prevalence of malignancy in indeterminate lesions ranged from 4.8% to 10.7% using SRU guidelines and IOTA simple rules, respectively [45]. Lesions that are not classically benign appearing have a risk of malignancy ranging from 8% to 50% [55]. CT Pelvis With IV Contrast CT pelvis with IV contrast is usually not useful in further characterization of indeterminate adnexal masses. Because the role of MRI is well established, there is little reason presently to obtain a CT for further characterization of an indeterminate lesion.


Clinically Suspected Adnexal Mass No Acute Symptoms. CT Pelvis Without and With IV Contrast CT pelvis without and with IV contrast is usually not useful in further characterization of indeterminate adnexal masses. Because the role of MRI is well established, there is little reason presently to obtain a CT for further characterization of an indeterminate lesion. Clinically Suspected Adnexal Mass CT Pelvis Without IV Contrast CT pelvis without IV contrast is usually not useful in further characterization of indeterminate adnexal masses. Because the role of MRI is well established, there is little reason presently to obtain a CT for further characterization of an indeterminate lesion. FDG-PET/CT Skull Base to Mid-Thigh PET/CT cannot reliability differentiate between benign and malignant adnexal lesions [63]. In premenopausal women, normal ovaries with late follicular or early luteal cysts can have mildly increased uptake [64]. Although maximum standardized update value (SUVmax) are higher in malignant tumors and low in benign lesions, there is no clear SUVmax cutoff value to differentiate the two [65]. Additionally, PET/CT cannot reliably differentiate between borderline tumors and benign lesions and has low uptake on clear cell and mucinous invasive adenocarcinoma subtypes [66,67]. Although PET-avid lesions in postmenopausal women are concerning for malignancy, its use to detect primary cancer is not recommended [68]. MRI Pelvis Without and With IV Contrast MRI is the most useful modality for further evaluation of the subset of lesions that remain indeterminate after sonographic evaluation [69]. A recent study assessing the SRU guidelines ability to risk stratify lesions demonstrated potential of MRI to decrease surgical evaluation for benign cysts by 89% [44]. MRI has an excellent accuracy of >90% for the diagnosis of malignancy [69-71]. MRI can accurately identify solid tissue from nonsolid tissue such as fat, blood, or debris that may appear solid on initial US [72].


Clinically Suspected Adnexal Mass No Acute Symptoms. MRI can also help determine the origin of the lesion, with up to 9% of presumed adnexal lesions on US being nonadnexal origin [73]. Sonographically visualized lesions >10 cm may need contrast-enhanced MRI to ensure complete visualization and assessment of the lesion and ensure there are no associated solid components. The presence or absence of enhancing solid tissue and enhancement curve characteristics as evaluated on perfusion dynamic contrast-enhanced imaging drives the risk of malignancy on MRI [17,69,71,74-80]. The absence of enhancement renders the risk of malignancy to nearly 0%, which is of particular value in the sonographically indeterminate lesions because it confirms the benignity of the lesion [71]. Solid tissue with time intensity curves (TIC) with rapid enhancement greater than the myometrium (type 3) are only found in invasive malignant tumors with a sensitivity of 67% versus slow low level enhancement (type 1) found in benign tumors with a sensitively of 70% and specificity of 89% [79]. Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values of benign and malignant lesions overlap, with Fujii et al [81] demonstrating teratomas, some endometriomas, and malignant tumors demonstrating abnormal DWI signal. The primary value of DWI is in the setting of a low T2 signal mass, with low signal on DWI predicting a high likelihood of benignity [69,81,82]. MRI Pelvis Without IV Contrast Contrast-enhanced MRI performs superiorly to both US and noncontrast MRI due to its ability to confirm the presence of internal enhancing soft tissue components [18]. Both the ADNEX and O-RADS MRI risk stratification systems will have some decreased usefulness in the noncontrast setting given the limited ability to identify enhancing solid tissue and its enhancement pattern, both crucial for characterizing indeterminate lesions [17,71,73].


Clinically Suspected Adnexal Mass No Acute Symptoms. For example, the overall specificity for malignancy of the ADNEX MR system falls below 90% if used without dynamic contrast enhancement [71,87]. Sahin et al [19] proposed a noncontrast MRI score based on ADNEX and O-RADS models using morphologic assessment and DWI with an 84.9% sensitivity, 95.9% specificity, and 94% accuracy with the caveat of a population with a lower malignancy rate (15.1%) than the original ADNEX and O- RADS models population (18.8% and 18.4%). Noncontrast MRI may be used in adnexal mass characterization when the use of IV contrast is precluded. Clinically Suspected Adnexal Mass Variant 5: Adult patient assigned female at birth. Adnexal mass, indeterminate on initial pelvic US, no acute symptoms. Premenopausal. Follow-up imaging. CT Pelvis With IV Contrast CT pelvis with IV contrast is usually not useful for follow-up of an indeterminate adnexal mass. Because the role of US and MRI is well established, there is little reason presently to obtain a CT for follow-up of an indeterminate lesion. CT Pelvis Without and With IV Contrast CT pelvis without and with IV contrast is usually not useful for follow-up of an indeterminate adnexal mass. Because the role of US and MRI is well established, there is little reason presently to obtain a CT for follow-up of an indeterminate lesion. CT Pelvis Without IV Contrast CT pelvis without IV contrast is usually not useful for follow-up of an indeterminate adnexal mass. Because the role of US and MRI is well established, there is little reason presently to obtain a CT for follow-up of an indeterminate lesion. FDG-PET/CT Skull Base to Mid-Thigh There is no role for the use of FDG-PET/CT in the follow-up of indeterminate adnexal masses in premenopausal patients. MRI Pelvis Without and With IV Contrast An indeterminate mass can be followed by contrast-enhanced MRI. This is helpful if the mass cannot be optimally visualized by US or if the mass shows suspicious change of appearance during US surveillance.


Clinically Suspected Adnexal Mass No Acute Symptoms. Suspected classic lesions (cysts, endometriomas, dermoid) >10 cm, which are suboptimally seen on US due to size, can be confirmed as almost certainly benign, which may alter further imaging follow-up intervals [17]. MRI Pelvis Without IV Contrast Contrast-enhanced MRI performs superiorly to both US and noncontrast MRI due to its ability to confirm the presence of internal enhancing soft tissue components [18]. Both the ADNEX and O-RADS MRI risk stratification systems will have some decreased usefulness in the noncontrast setting given the limited ability to identify enhancing solid tissue and its enhancement pattern, both crucial for characterizing indeterminate lesions [17,71,73]. For example, the overall specificity for malignancy of the ADNEX MR system falls below 90% if used without dynamic contrast enhancement [71,87]. Sahin et al [19] proposed a noncontrast MRI score based on ADNEX and O-RADS models using morphologic assessment and DWI with an 84.9% sensitivity, 95.9% specificity, and 94% accuracy with the caveat of a population with a lower malignancy rate (15.1%) than the original ADNEX and O- RADS models population (18.8% and 18.4%). Noncontrast MRI may be used in adnexal mass characterization when the use of IV contrast is precluded. US Duplex Doppler Pelvis Color or power Doppler should be included in the US examination of the pelvis. Color Duplex is used to evaluate vascularity of any developing solid component. US Pelvis Transabdominal Transabdominal US may be performed without transvaginal imaging when the transvaginal examination cannot be tolerated. The bladder should be full to provide the best acoustic window for evaluation. US Pelvis Transabdominal and US Pelvis Transvaginal Indeterminate lesions are typically benign. In a multicenter prospective study of 303 indeterminate adnexal cysts, the incidence of malignancy was 3.6% [61].


Clinically Suspected Adnexal Mass No Acute Symptoms. In a second multicenter prospective study of 697 women, the prevalence of malignancy in indeterminate lesions ranged from 4.8% to 10.7% using SRU guidelines and IOTA simple rules, respectively [45]. If an indeterminate mass is identified on initial US, then follow-up may be performed either by serial US or by MRI. For example, the former may be helpful to assess a suspected atypical appearing hemorrhagic cyst that is either resolving or undergoing evolution. A reasonable time frame for US follow-up in this setting would be 8 to 12 weeks (as is performed in typical hemorrhagic cysts of larger size in premenopausal women) to permit time for resolution or confirm persistence of a nonphysiologic cyst [23]. If the lesion persists and is stable in size and appearance, further evaluation with MRI may be appropriate, depending on the clinical context and features present. Clinically Suspected Adnexal Mass MRI may be able to assign a specific benign diagnosis or stratify for risk of malignancy, thus requiring no further US follow-up in the majority of cases [17,73]. If not requiring surgical management, indeterminate lesions that are well seen on US may be followed sonographically. US Pelvis Transvaginal The most useful modality for evaluation of adnexal masses includes transvaginal US combined with transabdominal US approach. Variant 6: Adult patient assigned female at birth. Adnexal mass, indeterminate on initial pelvic US, no acute symptoms. Postmenopausal. Follow-up imaging. CT Pelvis With IV Contrast CT pelvis with IV contrast is usually not useful for follow-up of an indeterminate adnexal mass. Because the role of US and MRI is well established, there is little reason presently to obtain a CT for follow-up of an indeterminate lesion. CT Pelvis Without and With IV Contrast CT pelvis without and with IV contrast is usually not useful for follow-up of an indeterminate adnexal mass.


Clinically Suspected Adnexal Mass No Acute Symptoms. Because the role of US and MRI is well established, there is little reason presently to obtain a CT for follow-up of an indeterminate lesion. CT Pelvis Without IV Contrast CT pelvis without IV contrast is usually not useful for follow-up of an indeterminate adnexal mass. Because the role of US and MRI is well established, there is little reason presently to obtain a CT for follow-up of an indeterminate lesion. FDG-PET/CT Skull Base to Mid-Thigh There is no role for the use of FDG-PET/CT in the follow-up of indeterminate adnexal masses in postmenopausal patients. MRI Pelvis Without and With IV Contrast An indeterminate mass can be followed by contrast-enhanced MRI. This is helpful if the mass cannot be optimally visualized by US or if the mass shows suspicious change of appearance during US surveillance. Suspected ovarian thecoma-fibroma group tumors, typically classified as indeterminate based on US features can go on further imaging with MRI, with characteristics feature of T2 homogeneous hypointensity and low signal on DWI rendering the lesion almost certainly benign [17,88]. MRI Pelvis Without IV Contrast Contrast-enhanced MRI performs superiorly to both US and noncontrast MRI due to its ability to confirm the presence of internal enhancing soft tissue components [18]. Both the ADNEX and O-RADS MRI risk stratification systems will have some decreased usefulness in the noncontrast setting given the limited ability to identify enhancing solid tissue and its enhancement pattern, both crucial for characterizing indeterminate lesions [17,71,73]. For example, the overall specificity for malignancy of the ADNEX MR system falls below 90% if used without dynamic contrast enhancement [71,87].


Clinically Suspected Adnexal Mass No Acute Symptoms. Sahin et al [19] proposed a noncontrast MRI score based on ADNEX and O-RADS models using morphologic assessment and DWI with an 84.9% sensitivity, 95.9% specificity, and 94% accuracy with the caveat of a population with a lower malignancy rate (15.1%) than the original ADNEX and O- RADS models population (18.8% and 18.4%). Noncontrast MRI may be used in adnexal mass characterization when the use of IV contrast is precluded. US Duplex Doppler Pelvis Color or power Doppler should be included in the US examination of the pelvis. Color Duplex is used to evaluate vascularity of any developing solid component. US Pelvis Transabdominal Transabdominal US may be performed without transvaginal imaging when the transvaginal examination cannot be tolerated or is contraindicated (eg, no prior history of sexual activity). The bladder should be full to provide the best acoustic window for evaluation. Clinically Suspected Adnexal Mass US Pelvis Transabdominal and US Pelvis Transvaginal Indeterminate lesions are typically benign. In a multicenter prospective study of 303 indeterminate adnexal cysts, the incidence of malignancy was 3.6% [61]. In a second multicenter prospective study of 697 women, the prevalence of malignancy in indeterminate lesions ranged from 4.8% to 10.7% using SRU guidelines and IOTA simple rules, respectively [45]. If an indeterminate mass is identified on initial US, then follow-up may be performed either by serial US or by MRI. In a study of 1,363 postmenopausal women, complex adnexal masses ranging in size from 1 to 6 cm had an overall low risk of malignancy of 1.3%, with all epithelial cancer and borderline tumors demonstrating growth by 7 months of sonographic observation [89]. Similarly, in women diagnosed with early-stage high-grade serous cancers, these were rarely <5 cm or without solid components other than septations, further supporting potential observation in small masses [90].


Clinically Suspected Adnexal Mass No Acute Symptoms. Solid hypoechoic masses with smooth margins and acoustic shadowing and minimal Doppler flow are characteristic features of ovarian thecoma-fibroma group tumors, sex cord stromal neoplasms most commonly seen in the postmenopausal patient [91]. In a small study of 99 benign-appearing smooth purely solid masses, those with IOTA color score of 1 or 2, the risk of malignancy at 3 year follow-up was low, at 2%, suggesting conservative management may be an option for some patients with serial US imaging follow-up [92]. MRI may be able to assign a specific benign diagnosis or stratify for risk of malignancy, which may alter further imaging follow-up intervals [17,73]. If not requiring surgical management, indeterminate lesions that are well seen on US may be followed sonographically. US Pelvis Transvaginal The most useful modality for evaluation of adnexal masses includes transvaginal US combined with transabdominal US approach. CT Pelvis Without and With IV Contrast CT pelvis without and with IV contrast is not useful for further characterization of a suspicious adnexal lesion. Although not supported by the existing literature, CT of the pelvis without and with IV contrast may be potentially useful to determine if a suspected solid component within an adnexal lesion demonstrates enhancement. CT Pelvis Without IV Contrast CT pelvis without IV contrast is not useful for further characterization of a suspicious adnexal lesion. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT is useful for staging of ovarian cancer, specifically for identifying other sites of disease, and with better detection of lymph node metastasis than conventional CT [93]. MRI Pelvis Without and With IV Contrast On US, solid adnexal lesions with irregular contour are highly suspicious for malignancy with a 93% PPV for malignancy [24]. Similarly, lesions with >4 papillary structures or solid tissue with increased color or spectral Doppler flow are concerning for malignancy [34,37,62].


Clinically Suspected Adnexal Mass No Acute Symptoms. When a lesion has sonographic features worrisome for malignancy, the PPV of cancer ranges from 29% to 50% [23,45,55,61,62]. For example, in a prospective multicenter study of 970 lesions, solid component with blood flow had a 32% frequency of malignancy and up to 50% in women >60 years of age [55]. Contrast-enhanced MRI can be used to increase the specificity for malignancy, which may aid in surgical decision making and preoperative planning [17,71,73]. The presence or absence of enhancing solid tissue and enhancement Clinically Suspected Adnexal Mass curve characteristics as evaluated on perfusion dynamic contrast-enhanced imaging drives the risk of malignancy on MRI [17,69,71,74-80]. Solid components with TIC with rapid enhancement greater than the myometrium (type 3) are only found in invasive malignant tumors with a sensitivity of 67% versus slow low level enhancement (type 1) found in benign tumors with a sensitively of 70% and specificity of 89% [79]. Evaluation with TIC performs better than visual assessment with respective sensitivities of 96% and 76% in detection of borderline and invasive tumors in a set of 320 lesions [94]. MRI Pelvis Without IV Contrast Contrast-enhanced MRI performs superiorly to both US and noncontrast MRI due to its ability to confirm the presence of internal enhancing soft tissue components [18]. Both the ADNEX and O-RADS MRI risk stratification systems will have some decreased usefulness in the noncontrast setting given the limited ability to identify enhancing solid tissue and its enhancement pattern, both crucial for characterizing indeterminate lesions [17,71,73]. For example, the overall specificity for malignancy of the ADNEX MR system falls below 90% if used without dynamic contrast enhancement [71,87].


Clinically Suspected Adnexal Mass No Acute Symptoms. Sahin et al [19] proposed a noncontrast MRI score based on ADNEX and O-RADS models using morphologic assessment and DWI with an 84.9% sensitivity, 95.9% specificity, and 94% accuracy with the caveat of a population with a lower malignancy rate (15.1%) than the original ADNEX and O- RADS models population (18.8% and 18.4%). Noncontrast MRI may be used in adnexal mass characterization when the use of IV contrast is precluded. Variant 8: Clinically suspected adnexal mass, no acute symptoms. Pregnant. Initial imaging. CT Pelvis With IV Contrast CT pelvis with IV contrast has no role in the initial evaluation for an adnexal lesion and should be avoided in pregnant patients due to radiation dose. CT Pelvis Without and With IV Contrast CT pelvis without and with IV contrast has no role in the initial evaluation for an adnexal lesion and should be avoided in pregnant patients due to radiation dose. CT Pelvis Without IV Contrast CT pelvis without IV contrast has no role in the initial evaluation for an adnexal lesion and should be avoided in pregnant patients due to radiation dose. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT has no role in the initial evaluation for an adnexal lesion and should be avoided in pregnant patients due to radiation dose. MRI Pelvis Without and With IV Contrast Gadolinium-based contrast agents should not be routinely administered to pregnant patients [95]. Free gadolinium is toxic and thus administered in its chelated form. Gadolinium has been shown to cross the placenta and enter fetal circulation in nonhuman primate models. It has potential but is unclear or has unknown risks of exposure to the developing fetus [95,96]. A study by Ray et al [97] in 2016 showed a slightly increased risk of stillbirth or neonatal death (17.6/1,000 in exposed fetuses versus 6.9/1,000 in fetuses not undergoing MRI) and a slightly increased risk of childhood rheumatological, inflammatory, or infiltrative skin conditions.


Clinically Suspected Adnexal Mass No Acute Symptoms. Gadolinium-based contrast agents are category C drugs as determined by the FDA, with adverse effects in animal studies without adequate studies in humans, and their use in pregnancy is restricted to situations where the potential benefits of imaging far outweigh the potential risk to the fetus [98]. A study by Thomassin-Naggara et al [99] in 2017 demonstrated an overall accuracy of MRI in up to 88% in pregnant patients using the ADNEX MR score in a subset of 36 masses. In this study, 7 of 31 patients received gadolinium contrast based on radiologist discretion during the examination, with all 7 demonstrating malignant tumors on final pathology. MRI Pelvis Without IV Contrast Although MRI can accurately diagnose the presence of adnexal lesions and identify distinguishing characteristics such as the type of fluid content, presence of fat, or presence of septations in cystic lesions [16,17], it is not the first- line modality for initial evaluation. MRI does not use ionizing radiation and is deemed safe in pregnant patients [95]. Although contrast-enhanced MRI performs superiorly to both US and noncontrast MRI due to its ability to confirm the presence of internal enhancing soft tissue components [18], gadolinium-based contrast agents should not be routinely administered to pregnant patients [95]. Although not specifically assessed in the pregnant Clinically Suspected Adnexal Mass population, in a recent study of 350 lesions in a population with 15% malignant lesions, noncontrast MRI demonstrated a sensitivity of 85%, specificity of 96%, and accuracy of 94.2% to detect cancer [19]. If a pregnant patient with a suspected adnexal lesion is unable to be evaluated via US (due to large size of lesion >10 cm, poor acoustic window from adjacent viscera or body habitus, or unclear organ of origin), noncontrast MRI would be the best alternative imaging modality for evaluation.


Clinically Suspected Adnexal Mass No Acute Symptoms. US Pelvis Transabdominal Although the most useful modality for the evaluation of adnexal masses is combined transabdominal and transvaginal pelvis US, a sole transabdominal approach is reasonable and may be the best option for the assessment of adnexal lesions late in gestation when the ovaries are displaced higher in the pelvis. US-based ovarian scoring systems have been applied to adnexal lesions in pregnant patients in a limited fashion in a few small studies. Czekierdowski et al [112] compared subjective assessment, Simple Rules Risk, and ADNEX models and found that subjective assessment performed best in a small study of 36 patients. Another larger study by Lee et al [113] with 236 women compared IOTA ADNEX and Sassone and Lerner systems, with the Sassone system or a combined model using 6 features that were found to be significant in their study performing the best. Clinically Suspected Adnexal Mass US Pelvis Transvaginal The most useful modality for evaluation of adnexal masses includes transvaginal US combined with transabdominal US approach. Variant 9: Adnexal mass, indeterminate on initial pelvic US, no acute symptoms. Pregnant. Next imaging study for characterization. CT Pelvis With IV Contrast CT pelvis with IV contrast has no role in the further characterization for an indeterminate adnexal lesion and should be avoided in pregnant patients due to radiation dose. CT Pelvis Without and With IV Contrast CT pelvis without and with IV contrast has no role in the further characterization for an indeterminate adnexal lesion and should be avoided in pregnant patients due to radiation dose. CT Pelvis Without IV Contrast CT pelvis without IV contrast has no role in the further characterization for an indeterminate adnexal lesion and should be avoided in pregnant patients due to radiation dose.


Clinically Suspected Adnexal Mass No Acute Symptoms. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT has no role in further characterization of an indeterminate adnexal lesion in pregnancy, given the accuracy of US and MRI. MRI Pelvis Without and With IV Contrast Gadolinium-based contrast agents should not be routinely administered to pregnant patients [95]. Free gadolinium is toxic and thus administered in its chelated form. Gadolinium has been shown to cross the placenta and enter fetal circulation in nonhuman primate models. It has potential but is unclear or has unknown risks of exposure to the developing fetus [95,96]. A study by Ray et al [97] in 2016 showed a slightly increased risk of stillbirth or neonatal death (17.6/1,000 in exposed fetuses versus 6.9/1,000 in fetuses not undergoing MRI) and slightly increased risk of childhood rheumatological, inflammatory, or infiltrative skin conditions. Gadolinium-based contrast agents are category C drugs as determined by the FDA, with adverse effects in animal studies without adequate studies in humans, and their use in pregnancy is restricted to situations where the potential benefits of imaging far outweigh the potential risk to the fetus [98]. A study by Thomassin-Naggara et al [99] in 2017 demonstrated an overall accuracy of MRI in up to 88% in pregnant patients using the ADNEX MR score in a subset of 36 masses. In this study, 7 of 31 patients received gadolinium contrast based on radiologist discretion during the examination, with all 7 demonstrating malignant tumors on final pathology. MRI Pelvis Without IV Contrast MRI without contrast is useful for the evaluation of an US indeterminate adnexal lesion in pregnant patients who cannot receive gadolinium. MRI does not use ionizing radiation and is deemed safe in pregnant patients [95]. Up to 22% to 24% of adnexal masses remain indeterminate after US evaluation [61,62]. MRI can be helpful in the setting of indeterminate masses, large lesions >10 cm in size, and determination of origin in adnexal masses.


Chronic Knee Pain

Chronic Knee Pain.  Variant 2: Adult or child greater than or equal to 5 years of age. Chronic knee pain. Initial knee radiograph negative or demonstrates joint effusion. Next imaging procedure. Chronic Knee Pain Variant 3: Adult or child greater than or equal to 5 years of age. Chronic knee pain. Initial knee radiograph demonstrates osteochondritis dissecans (OCD), loose bodies, or history of cartilage or meniscal repair. Next imaging procedure. Variant 4: Adult or child greater than or equal to 5 years of age. Chronic knee pain. Initial knee imaging radiograph demonstrates degenerative changes or chondrocalcinosis. Next procedure. Chronic Knee Pain Variant 5: Adult or child greater than or equal to 5 years of age. Chronic knee pain. Initial knee radiograph demonstrates signs of prior osseous injury (ie, Segond fracture, tibial spine avulsion, etc). Next imaging procedure. Chronic Knee Pain CHRONIC KNEE PAIN Expert Panel on Musculoskeletal Imaging: Michael G. Fox, MD, MBAa; Eric Y. Chang, MDb; Behrang Amini, MD, PhDc; Stephanie A. Bernard, MDd; Tetyana Gorbachova, MDe; Alice S. Ha, MDf; Ramesh S. Iyer, MDg; Kenneth S. Lee, MD, MBAh; Darlene F. Metter, MDi; Pekka A. Mooar, MDj; Nehal A. Shah, MDk; Adam D. Singer, MDl; Stacy E. Smith, MDm; Mihra S. Taljanovic, MD, PhDn; Ralf Thiele, MDo; Kathy M. Tynus, MDp; Mark J. Kransdorf, MD. q Typically, radiography is the initial imaging study used to evaluate chronic pain in a native knee. When pain persists but the initial radiographs are normal or demonstrate a joint effusion, MRI is usually considered the next imaging study. However, the use of MRI may be premature and unnecessary in some patients, as it is estimated that approximately 20% of patients with chronic knee pain have had an MRI performed without recent (within the prior year) radiographs [2].


Chronic Knee Pain

Chronic Knee Pain. Special Imaging Considerations Knee radiographs should include at least one frontal projection of one or both knees (anteroposterior, Rosenberg, or tunnel), a tangential patellar view, and a lateral view of the affected knee [2,9]. Standing radiographs more accurately reflect medial and lateral compartment cartilage loss than supine radiographs with the posteromedial and posterolateral joint compartments more accurately assessed using a weight-bearing flexion posteroanterior radiograph [9,10]. Discussion of Procedures by Variant Variant 1: Adult or child greater than or equal to 5 years of age. Chronic knee pain. Initial imaging. Radiography Knee Radiographs should be the initial imaging study for chronic knee pain. In elderly patients, the most common source of chronic knee pain is osteoarthritis. Conventional radiographic diagnosis of osteoarthritis includes joint space narrowing, osteophytes, subchondral cysts, and subarticular sclerosis [11]. Articular cartilage is evaluated Reprint requests to: publications@acr.org Chronic Knee Pain Radiography Hip An ipsilateral hip radiograph is usually not indicated as a first imaging examination. CT Knee CT is usually not indicated as a first imaging examination. CT Arthrography Knee CT arthrography is usually not indicated as a first imaging examination. MRI Knee MRI is usually not indicated as a first imaging examination. To avoid unnecessary MRI, assessment of current radiographs (within the prior year) is required [2]. MR Arthrography Knee MR arthrography is usually not indicated as a first imaging examination. US Knee Ultrasound (US) is usually not indicated as a first imaging examination. Bone Scan Knee Radionuclide bone scan is usually not indicated as a first imaging examination. Image-Guided Aspiration Knee Joint aspiration is usually not indicated as a first imaging examination. Variant 2: Adult or child greater than or equal to 5 years of age. Chronic knee pain. Initial knee radiograph negative or demonstrates joint effusion.


Chronic Knee Pain

Chronic Knee Pain. Next imaging procedure. Radiography Hip In patients with chronic knee pain, referred pain from the hip must be considered, especially if the knee radiographs are unremarkable and there is clinical evidence or concern for hip pathology [14]. Radiography Lumbar Spine In patients with chronic knee pain, referred pain from the lower back must be considered, especially if the knee radiographs are unremarkable and there is clinical evidence or concern for lumbar spine pathology. CT Knee CT without intravenous (IV) contrast may be indicated to evaluate the patellofemoral anatomy in the setting of chronic knee pain related to repetitive patellofemoral subluxation or maltracking [15]. CT can also be used to evaluate trochlear morphology and the tibial tubercle-trochlear groove distance. CT with IV contrast is usually not indicated when initial radiograph is negative or demonstrates a joint effusion. CT without and with IV contrast is not routinely performed when initial radiographs are negative. CT Arthrography Knee When an intra-articular abnormality is suspected, CT arthrography may be used instead of MRI to evaluate the menisci and articular cartilage [16]. MRI Knee When initial radiographs are normal or reveal a joint effusion but pain persists, the next indicated study is usually MRI without IV contrast, which is more sensitive than radiography [11]. MRI accurately depicts the extent of an effusion, presence of synovitis, and presence or rupture of a popliteal cyst [17]. Subchondral cysts, articular cartilage, and meniscal abnormalities are easily detected on MRI [13,18,19]. However, meniscal tears are often incidental findings in older patients with the majority of people over 70 years Chronic Knee Pain of age having an asymptomatic meniscal tear, and the likelihood of a meniscal tear being present in either a painful or asymptomatic knee not significantly different in patients 45 to 55 years of age [20,21].


Chronic Knee Pain

Chronic Knee Pain. Bone marrow lesions (BML) are readily depicted on MRI as areas of increased edema-like signal in the subchondral bone. New or increasing BMLs are associated with increased knee pain, especially in males or patients with family history of osteoarthritis [22]. Conversely, decreasing BMLs are associated with reduced knee pain [23]. A systematic review of 22 articles concluded that both BMLs and synovitis/effusion may indicate the origin of knee pain in patients with osteoarthritis [24-26]. Some patients with normal knee radiographs and anterior knee pain have abnormal cartilage on 3 T MRI using quantitative imaging [29]. In particular, patients 45 to 55 years of age with knee pain but normal radiographs exhibited elevated T2 mapping values on 3 T MRI [20]. Patellofemoral cartilage loss is also associated with chronic knee pain, with active knee pain correlated with BMLs [30,31]. Similar to CT, MRI can calculate various anatomic measurements associated with patellofemoral subluxation/dislocation and lateral patellofemoral friction syndrome [32-34]. Bone marrow edema in the classic location for patellofemoral dislocation/relocation injuries is also identified by MRI [15]. MRI may also differentiate patients with more severe patellofemoral osteoarthritis who may not benefit from supervised exercise therapy from patients with medial or lateral knee compartment arthritis who might benefit [35]. MR Arthrography Knee MR arthrography performed with an intra-articular injection of dilute gadolinium solution is typically not indicated as a second examination but rather reserved for patients with known prior meniscal surgery, chondral and osteochondral lesions, and suspected loose bodies [10]. US Knee US is not often useful as a screening test or a comprehensive examination. It may be appropriate to confirm a suspected effusion and to guide a potential aspiration [10]. US is as accurate in diagnosing a popliteal cyst and detecting cyst rupture when compared to MRI [10].


Chronic Knee Pain

Chronic Knee Pain. US is also useful in evaluating medial plicae and following patients with iliotibial band syndrome [17,44]. More recently, shear wave elastography has been used to evaluate female patients with patellofemoral pain by demonstrating reduced contraction ratio in the vastus medialis oblique but not the vastus lateralis muscles [49]. Finally, US can diagnose a cyst and determine the vascularity of a mass [37]. Bone Scan Knee Radionuclide bone scan is usually not indicated when initial radiograph is negative or demonstrates a joint effusion. Chronic Knee Pain Image-Guided Aspiration Knee If an aspiration for crystals or atypical/low-grade chronic infection is indicated, it can be facilitated by US or fluoroscopy [10]. Variant 3: Adult or child greater than or equal to 5 years of age. Chronic knee pain. Initial knee radiograph demonstrates osteochondritis dissecans (OCD), loose bodies, or history of cartilage or meniscal repair. Next imaging procedure. Radiography Hip An ipsilateral hip radiograph is usually not indicated to evaluate patients with osteochondritis dissecans (OCD), loose bodies, or history of cartilage repair. CT Knee CT without IV contrast may be indicated to evaluate patients with OCD or a history of cartilage repair, especially to confirm loose bodies or when MRI is not definitive. CT with IV contrast is not usually indicated to evaluate patients with OCD, loose bodies, or history of cartilage repair. CT without and with IV contrast is not usually indicated to evaluate patients with OCD, loose bodies, or history of cartilage repair. CT Arthrography Knee CT arthrography may be used instead of MRI to evaluate the menisci, articular cartilage, and the presence of loose bodies [16]. MRI Knee In patients with OCD or subchondral insufficiency fracture on radiographs, MRI without IV contrast may be indicated if an additional injury is suspected clinically or to clarify the status of the overlying articular cartilage [41].


Chronic Knee Pain

Chronic Knee Pain. A hyperintense rim or cysts at the osteochondral fragment periphery on MRI are less specific for OCD fragment instability in children compared to adults; however, MRI is still useful to determine the best method of treatment [41,50]. Following cartilage repair, MRI can grade the repair site and even guide the retrograde drilling of the OCD lesion [51-54]. MRI with and without IV contrast is not usually indicated to evaluate patients with OCD, loose bodies, or history of cartilage repair because of the usual larger volume of joint fluid, the lesser degree of synovial invagination, and the longer time required to achieve steady state gadolinium in the joint compared to the shoulder [16]. MR Arthrography Knee MR arthrography is typically reserved for patients with known prior meniscal surgery, chondral and osteochondral lesions, prior cartilage repair procedures, or suspected loose bodies [10,16]. US Knee US is not often useful as a screening test or a comprehensive examination. It may be appropriate to localize suspected loose bodies, especially if the loose bodies might be within a popliteal cyst, lateral recess, or suprapatellar recess. Bone Scan Knee Radionuclide bone scan is usually not indicated to evaluate patients with OCD, loose bodies, or history of cartilage repair. Image-Guided Aspiration Knee Joint aspiration is usually not indicated to evaluate patients with OCD, loose bodies, or history of cartilage repair. Variant 4: Adult or child greater than or equal to 5 years of age. Chronic knee pain. Initial knee radiograph demonstrates degenerative changes or chondrocalcinosis. Next imaging procedure. Radiography Hip An ipsilateral hip radiograph is usually not indicated to evaluate patients with osteoarthritis or chondrocalcinosis. Chronic Knee Pain CT Knee Dual-energy CT without IV contrast may be indicated if gout or mixed crystal disease is a consideration. Otherwise, CT is not commonly used as a diagnostic test to evaluate patients with osteoarthritis or chondrocalcinosis.


Chronic Knee Pain

Chronic Knee Pain. Limited CT without IV contrast can be used for surgical planning. CT Arthrography Knee CT arthrography is not commonly utilized as a second test in patients with arthritis even though CT is the most accurate method for evaluating cartilage abnormalities extending to the articular surface that is due to the high spatial resolution between the contrast and the cartilage [11]. MRI Knee MRI without IV contrast is not usually indicated in patients for whom radiographs are diagnostic of osteoarthritis unless symptoms are not explained by the radiographic findings (eg, stress fractures) or the appropriate treatment option requires additional imaging [11,19]. Patellofemoral cartilage loss is closely associated with chronic knee pain with active knee pain correlated with BMLs [56]. Since MRI is more accurate than physical examination in identifying severe grades of chondromalacia patellae, it may be an appropriate screening tool prior to arthroscopy [58]. MR Arthrography Knee MR arthrography is usually not indicated to evaluate patients with osteoarthritis or chondrocalcinosis. US Knee US is not often useful as a screening test or a comprehensive examination. US can detect synovial pathology, effusions, and cortical erosive changes [11]. Power Doppler US can demonstrate increased synovial blood flow that is associated with knee pain and can demonstrate reduced blood flow, which correlates with reduced knee pain following joint injections [60]. US can also demonstrate meniscal extrusion, a finding that suggests an underlying meniscal tear, and, on occasion, chondrocalcinosis and peripheral meniscal tears [11]. Bone Scan Knee Radionuclide bone scan is usually not indicated to evaluate patients with chronic knee pain given the low specificity and decreased anatomic resolution compared to CT or MRI [11]. However, it may help distinguish between bone and soft-tissue origins for pain as well as localize pain to one or more joints [11].


Chronic Knee Pain

Chronic Knee Pain. Image-Guided Aspiration Knee If an effusion is present, US- or fluoroscopically guided joint aspiration can be performed for synovial fluid analysis if there is concern for crystal disease or infection. Corticosteroid injections can also be performed as they may result in a 1 to 2 week reduction in synovitis on MRI in two-thirds of patients. MRI also demonstrates a subsequent increase in the synovial volume in approximately 70% of patients that develop recurrent pain [61]. Chronic Knee Pain Radiography Hip An ipsilateral hip radiograph is usually not indicated to evaluate patients with signs of prior (chronic) osseous knee injury. CT Knee CT without IV contrast may be indicated to evaluate the patellofemoral anatomy in the setting of chronic knee pain related to repetitive patellofemoral subluxation, which can be suggested by a small osseous fragment along the medial patellar margin on axial knee radiographs [15]. CT knee without IV contrast may also be useful to confirm a prior osseous injury. CT with IV contrast is not usually indicated to evaluate patients with signs of prior (chronic) osseous knee injury. CT without and with IV contrast is not usually indicated to evaluate patients with signs of prior (chronic) osseous knee injury. CT Arthrography Knee CT arthrography may be used to evaluate the menisci, articular cartilage, and the presence of loose bodies with reported sensitivities and specificities ranging from 86% to 100% [16,62-64]. MRI Knee MRI without IV contrast may be indicated when radiographs demonstrate a small osseous fragment along the medial patellar margin or if there is a clinical concern for prior or chronic patellar dislocation-relocation. MRI can assess the integrity of the medial patellofemoral ligament and medial patellar retinaculum, define the extent of cartilage injury, and identify loose bodies [41]. MRI is useful for evaluating Osgood-Schlatter or Sinding-Larsen- Johansson syndrome [41].


Hernia

Hernia.  Introduction/Background Abdominal wall hernias are common clinical entities presenting to a wide variety of clinical practices, from primary care to the emergency department. Presenting symptoms vary, including vague discomfort, intractable pain, or a palpable mass, which may be persistent or intermittent, symptoms of bowel obstruction, abdominal wall erythema, or it may be occult. Up to 15.2% of hernias are identified incidentally at imaging [1]. Hernias may be congenital, iatrogenic, traumatic, or related to any of the multiple causes of elevated intraabdominal pressure. The initial imaging in four hernia categories are covered in this document: 1) suspected abdominal wall hernia, such as umbilical, ventral, incisional, lumbar, spigelian; 2) suspected groin hernia, such as inguinal or femoral; 3) suspected deep pelvic hernia such as obturator, sciatic, perineal hernias; and 4) suspected diaphragmatic hernia such as traumatic, Bochdalek, or Morgagni. Imaging diagnosis of hiatal hernias is not included in this document. OR Reprint requests to: publications@acr.org Hernia Discussion of Procedures by Variant Variant 1: Suspected abdominal wall hernia such as umbilical, ventral, incisional, lumbar, or spigelian. Initial imaging. Surgical procedures create measurable alterations in the abdominal wall, which may be identified and quantified with cross-sectional imaging [5]. Shifts in relative position and atrophy of musculature are identified and may contribute to the development of incisional hernias. Abdominal wall hernias may be challenging to diagnose clinically and are prone to complications if not addressed in a timely fashion [6]. Diagnosis and presurgical planning may be achieved through several imaging modalities. Spigelian hernia is a rare form of hernia, occurring through a defect adjacent to the linea semilunaris with a reported incidence of 0.12% of all abdominal hernias [7].


Hernia

Hernia. They may be congenital, secondary to high-energy trauma such as motor vehicle collisions, or found in high-level athletes [8]. Presenting signs and symptoms may be vague and nonspecific. Clinical examination has demonstrated high sensitivity of 100%, but a poor positive predictive value (PPV) at 36% [9]. Primary lumbar hernias are protrusions of the abdominal contents through the superior or inferior lumbar triangles. The first branches of the iliolumbar vessels may pass through the superior triangle, found in 46% of patients in a series of 50 upper abdominal CTs evaluating triangle anatomy [10]. The second, third, and fourth lumbar nerve branches may traverse the inferior triangle and were found in 9%, 67%, and 8%, respectively. These anatomic channels may contribute to the development of hernias because they represent natural weak points in the abdominal wall. Umbilical hernia is a common abdominal wall defect because the healed site of traverse of the umbilical vasculature represents a congenital abdominal wall weak point. Umbilical hernias are associated with causes of increased intraabdominal pressure. Among these causes are ascites, bland and malignant, and masses [11,12]. Ascites volume in cirrhotic patients was positively associated with development of umbilical hernias (P < . 0001, r = 0.4579). In many cases, umbilical hernias become apparent during pregnancy. An ultrasound (US) examination of the abdominal wall in a series of 302 patients referred for unrelated reasons yielded a prevalence of paraumbilical hernia in 24.9% of women and 23.3% of men [13]. Diastasis recti, weakened linea alba without disruption, may have a similar presentation. If possible, width should be measured and reported. Clinically, incisional hernia is defined as a detectable abdominal wall defect following surgical intervention with protrusion of abdominal contents or preperitoneal fat beyond the aponeurosis. Incidence is variable and related to patient characteristics and procedure.


Hernia

Hernia. The rate of occurrence in laparoscopic procedures were as low as 2% [14]. However, the increased size of the fascial defect predisposes to increased incidence of port-site hernias. In a retrospective review of 787 patients who underwent single-incision laparoscopic procedures, Buckley et al [15] found that 2% to 6.35% developed port-site incisional hernias. Risk factors found to be associated with increased likelihood of developing an incisional hernia included pre-existing hernia (P = . 00212), body mass index (P = . 0307), and morbid obesity (P = . 02). In a series of 589 patients who underwent abdominal free flap reconstruction, Kappos et al [16] found symptomatic incisional hernias were significantly associated to low rectus abdominis muscle area, obtained through morphometric measurements on preoperative CT angiograms, and increased interrectus distance. Parastomal hernias are a specific type of incisional hernia seen most often in oncology patients. Rate of occurrence of parastomal hernias were found up to 65% in ileal conduits [17], and 30% to 50% of colostomies [18]. The majority of parastomal hernias in permanent colostomy patients occur within the first 2 years [19]. Complications include pain, stoma obstruction, bowel obstruction, and strangulation. Because the stoma itself is effectively an iatrogenic hernia, with a specific clinical purpose and necessary disruption of abdominal wall integrity, clinical diagnosis is difficult with interobserver kappa values of 0.29 to 0.73 [20]. Umbilical hernia is a common abdominal wall defect because the healed site of traverse of the umbilical vasculature represents a congenital abdominal wall weak point. Umbilical hernias are associated with causes of increased intraabdominal pressure. Among these causes are ascites, bland and malignant, and masses [11,12]. Ascites volume in cirrhotic patients was positively associated with development of umbilical hernias (P < . 0001, r = 0.4579).


Hernia

Hernia. An ultrasound (US) examination of the abdominal wall in a series of 302 patients referred for unrelated reasons yielded a prevalence of paraumbilical hernia in 24.9% of women and 23.3% of men [13]. Diastasis recti, weakened linea alba without disruption, may have a similar presentation. If possible, width should be measured and reported. Hernia CT Abdomen and Pelvis Incidence of incisional hernia of 33% was found by Bjork et al [21] with clinical examination yielding a Kappa of 0.81 and CT yielding Kappas of 0.94 and 0.89, respectively, for supine and prone positioning. In one series with surgical confirmation, CT demonstrated high sensitivity and PPV, both at 100%, in diagnosis of Spigelian hernia [9]. Stoma closure sites are common incisional weak points in the abdominal wall. CT demonstrates a low PPV of 33% with a high negative predictive value (NPV) of 95% in the diagnosis of parastomal hernia [22]. This compares favorably with a clinical detection rate of 14%. There are no specific data differentiating diagnostic efficacy of intravenous (IV) contrast versus noncontrast examination. There are no specific data regarding the use of CT without and with IV contrast, but theoretically, the additional information gained between comparison of a noncontrast and postcontrast series would not be beneficial for hernia detection and characterization. Fluoroscopy Upper GI Series There is no relevant literature regarding the use of fluoroscopy upper gastrointestinal (GI) series in the evaluation of abdominal wall hernia. Fluoroscopy Upper GI Series with Small Bowel Follow-Through Anterior abdominal wall hernia may be diagnosed with fluoroscopic studies. Barium is the most common contrast employed. Hernias are recognized when bowel loops are seen extending beyond the fascial planes, focal luminal narrowing at entry and/or exit sites, and displacement or deformity of bowel loops [23].


Hernia

Hernia. No specific data are available relative to the sensitivity, specificity, or accuracy of upper GI with small bowel follow-through in the diagnosis of abdominal wall hernias. MRI Abdomen Without and With IV Contrast There is no relevant literature regarding the use of MRI abdomen in the evaluation of abdominal wall hernia. However, the modality would be able to depict the anatomy, and theoretically, visualize a hernia. The specific performance attributes are unknown. MRI Abdomen Without IV Contrast There is no relevant literature regarding the use of MRI abdomen in the evaluation of abdominal wall hernia. However, the modality would be able to depict the anatomy, and theoretically, visualize a hernia. The specific performance attributes are unknown. MRI Pelvis There is no relevant literature regarding the use of MRI pelvis in the evaluation of abdominal wall hernia. However, the modality would be able to depict the anatomy, and theoretically, visualize a hernia. The specific performance attributes are unknown. Radiography Abdomen and Pelvis There is no relevant literature regarding the use of radiography abdomen and pelvis (KUB) in the evaluation of abdominal wall hernia. However, there may be utility if there is concern for bowel obstruction. US Abdomen US has long been used in the evaluation of the palpable abdominal masses. The ability to differentiate the abdominal wall from intraabdominal processes and distinguish the abdominal wall layers is well established. Use of high- frequency transducers and dynamic maneuvers frequently demonstrate the fascial defect and herniated abdominal structures with their characteristic US features [24]. In a case series with surgical confirmation of presence of Spigelian hernia, US demonstrated a sensitivity of 90% and a PPV of 100% [9]. Dynamic US demonstrated a high sensitivity, specificity, PPV, and NPV of 98%, 88%, 91%, and 97%, respectively, in the diagnosis of incisional hernias in a prospective study of 181 patients.


Hernia

Hernia. Patients with stoma, fistula, and/or abdominal wall infection were excluded [25]. US Pelvis There is no relevant literature regarding the use of US pelvis in the evaluation of abdominal wall hernia. Variant 2: Suspected groin hernia such as inguinal or femoral. Initial imaging. Inguinal hernias are common entities. Clinical diagnosis and differentiation of direct inguinal, indirect inguinal, and femoral hernias may be difficult. These hernias present in similar fashion with bulge, pain, and potentially signs and symptoms of bowel obstruction. In addition, the hernia may be occult, presenting with groin or pelvic pain in the absence of a palpable bulge or any other typical clinical examination findings. They may also present as an Hernia incidental finding in patients with athletic pub algia or chronic pain following herniorrh aphy [2 6,27]. Imag ing techniques p rovide visualization of the key anatomic landmarks and the relative position of herniated tissues, allowing differentiation of these entities. In addition, the impact of herniated tissues on the adjacent structures such as compression of the femoral vein in femoral hernia may be identified, aiding specific diagnosis [28]. CT Pelvis In a single prospective study, specifically evaluating CT imaging limited to the lower abdomen and pelvis evaluated prone patient positioning for hernia specific CT, there were 914 patients included in this prospective study and surgery was the reference standard. A prone CT protocol yielded an accuracy rate of 95.8% [33]. There are no specific data regarding the use of CT without and with IV contrast, but theoretically, the additional information gained between comparison of a noncontrast and postcontrast series would not be beneficial for hernia detection and characterization. Fluoroscopy Small Bowel Follow-Through There is no relevant literature regarding the use of fluoroscopy small bowel follow-through in the evaluation of groin, inguinal, or femoral hernia.


Hernia

Hernia. However, the modality would be able to depict the anatomy and, theoretically, visualize a hernia. The specific performance attributes are unknown. MRI Pelvis MRI is useful and can help visualize anatomic structures. In a retrospective review of 36 patients with suspected occult inguinal hernia, MRI demonstrated a sensitivity, a specificity, a PPV, and an NPV of 91%, 92%, 95%, and 85%, respectively, correctly diagnosing hernia in 10 of 11 patients [32]. In a retrospective review of 117 athletes who underwent MRI for groin pain, inguinal hernia was diagnosed in 35% of patients [26]. There are no specific data differentiating diagnostic efficacy of IV contrast versus noncontrast examination. Radiography Abdomen and Pelvis In case series of 170 and 204 herniographies for diagnosis of occult groin hernia, 49% and 35% were positive, respectively [34,35]. However, in the Ward et al study [35], 6 of 41 patients undergoing surgical repair, 16% were found to not have a hernia in the series. Whereas, in the Hachem et al study [34], all 84 patients with positive herniogram had hernia confirmed at surgery. In a third series of patients suspected of having occult inguinal hernia, herniography was found to have a sensitivity and specificity of 91% and 83%, respectively [31]. US Pelvis Diagnostic performance of US is common in the diagnosis of occult inguinal hernia. In a retrospect analysis of 297 patients, 116 went on to surgery. Based on surgical findings, US had a sensitivity of 94% with a PPV of 73% [36]. When US was performed by musculoskeletal experts, US had a sensitivity of 96.3% [37]. Hernia examination yielded a sensitivity and specificity of 96% [42]. In a case series of 18 consecutive pregnant patients with groin pain and swelling with clinical suspicion of hernia, hernia was not present in any patient and symptoms resolved following delivery [43]. Color Doppler US was positive for enlarged veins around the round ligament. Variant 3: Suspected deep pelvic hernia including obturator, sciatic, or perineal.


Hernia

Hernia. Initial imaging. Deep pelvis hernias are exceedingly rare, and little current literature is available, with the majority addressing obturator hernias and primarily case reports for the other entities. Obturator hernias comprise <1% of hernias [46]. Presenting symptoms are vague and varied and may be completely absent. Signs and symptoms include small- bowel obstruction (63%), vague and/or intractable abdominal/groin pain (57%), palpable medial thigh lump (10%), and thigh pain referred to the knee (37%) [46-48]. Referred pain is secondary to compression of the obturator nerve within the obturator foramen. Elderly women are most commonly affected, and diagnosis is most commonly made at surgery, often for inguinal hernia repair [47,49]. In a case series by Light et al [49] of 30 patients, 5 patients were suspected to have obturator hernia on clinical examination alone, with only 3 confirmed surgically. Because of the lack of specific symptoms and signs in the primarily elderly population, diagnosis is often delayed with significant morbidity (30%) and mortality (10%), with small-bowel resection performed in 47% of patients in one study [46,47]. Nasir et al [47], in a retrospective review, demonstrated diagnosis preoperatively in only 30% of patients, 3% clinically, and 27% with CT. Perineal hernias may be congenital or acquired. They are classified as anterior or posterior based on relative position to the superficial transverse perineal muscle [52]. Acquired perineal hernias are rare surgical complications, most often associated with oncologic surgeries for colorectal and genitourinary neoplasm such as abdominoperineal resection and cystectomy. Postprocedural pelvic floor weakening is implicated [53]. CT Abdomen and Pelvis Preoperative CT is excellent in diagnosing obturator hernia, although the diagnosis is seldom suspected, most often incidentally identified at abdominal pelvic imaging for the diagnosis of small-bowel obstruction.


Hernia

Hernia. Nasir et al [47], in a retrospective review, found that patients diagnosed with obturator hernia on preoperative CT are less likely to develop postoperative complications (odds ratio: 0.8, P = . 04). Preoperative diagnosis did not impact length of stay, bowel resection, or mortality rates. CT has also been found to be efficacious in the diagnosis of sciatic and perineal hernias [51,53]. Because of the infrequency of these entities and the majority of literature being in the form of case reports, sensitivities, specificities, and accuracy ranges are not available. There are no specific data differentiating diagnostic efficacy of an IV contrast versus noncontrast examination. There are no specific data regarding the use of CT without and with IV contrast, but theoretically, the additional information gained between comparison of a noncontrast and postcontrast series would not be beneficial for hernia detection and characterization. CT Pelvis Retrospective reviews of clinical databases regarding imaging diagnosis of these rare deep pelvic hernias do not separate abdominal pelvic CT from pelvic CT alone [47,51,53]. Depending upon the area of coverage, CT pelvis can be useful in diagnosis and pre-operative planning. There are no specific data differentiating diagnostic efficacy of an IV contrast versus noncontrast examination. There are no specific data regarding the use of CT without and with IV contrast, but theoretically, the additional information gained between comparison of a noncontrast and postcontrast series would not be beneficial for hernia detection and characterization. Of note, CT without and with IV contrast is not typically performed for this scenario. Hernia Fluoroscopy Small Bowel Follow-Through There is no relevant literature regarding the use of small bowel follow-through in the evaluation of deep pelvic hernia. However, demonstration of abnormal bowel configuration suggesting herniation may be helpful in complex cases.


Hernia

Hernia. MRI Pelvis No specific data are available relative to the sensitivity, specificity, or accuracy of MRI in the diagnosis of deep pelvic hernias. However, case reports demonstrate efficacy, particularly in patients with orthopedic instrumentation limiting CT imaging [54]. There are no specific data differentiating diagnostic efficacy of IV contrast versus noncontrast examination. However, the modality would be able to depict the anatomy, and theoretically, visualize a hernia. The specific performance attributes are unknown. Radiography Abdomen and Pelvis There is no relevant literature regarding the use of KUB in the evaluation of deep pelvic hernia. However, there may be utility if there is a concern for bowel obstruction. US Pelvis There is no relevant literature regarding the use of US of the pelvis in the evaluation of deep pelvic hernia. Variant 4: Suspected diaphragmatic hernia including traumatic, Bochdalek, or Morgagni. Initial imaging. Diaphragmatic hernias are rare and diagnosis may be difficult despite high -resolution multiplanar imaging techniques. Congenital, traumatic, and iatrogenic etiologies are evaluated primarily with CT and MRI. Congenital, Bochdalek and Morgagni hernias are most often diagnosed in the prenatal or neonatal period because o f abnormalities detected on obstetric US. Diagnosis of traumatic diaphragmatic rupture with herniation of abdominal contents into the thorax is often delayed because of subtle initial imaging findings and late herniation of abdominal contents into the thorax. Congenital diaphragmatic hernias are rare, occurring in approximately 1 per 2,000 pregnancies with 5% Morgagni and 90% Bochdalek hernias [55]. Most are diagnosed on prenatal imaging and present in the neonatal period with cardiorespiratory compromise and are surgically corrected. Bochdalek hernias are the result of improper fusion of the septum transversarium and pleuroperitoneal fo lds and are present in 1:2 ,200 to 12 ,500 live births [56,57] .


Hernia

Hernia. Morgagni hernia is a defect in the anterior diaphragm between the costal and sternal portions of the muscle [58]. Adult presentation is uncommon and usually an incidental finding on imaging performed for unrelated reasons. Retrospective review series of multidetector CT performed for unrelated indications identified Bochdalek hernia in 10.5% to 12.7% of adults [59,60]. However, these hernias may also present with acute symptoms related to complications of obstruction, perforation, or necrosis of the herniated organs [56,61-63]. CT Chest and Abdomen CT is an efficacious method for the diagnosis of traumatic diaphragmatic hernia with a sensitivity, a specificity, a PPV, an NPV, and an accuracy ranging from 56.5% to 82%, 69.6% to 100%, 69% to 100%, 88.4% to 93%, and 89% to 90.6%, respectively [64-66]. For the diagnosis of congenital hernia, there is particular emphasis on the utility of multiplanar technique [59-63,67- 69]. Data on sensitivity, specificity, and accuracy are not available because the majority of literature is comprised of case reports. There is n o specific data differentiating diagnostic efficacy of IV contrast versus n oncontrast examination. There is no specific data regarding the use of CT without and with IV contrast, but theoretically, the additional information gained between comparison of a noncontrast and postcontrast series would not be beneficial for hernia detection and characterization. Fluoroscopy Upper GI Series Upper GI diagnosed congenital diaphragmatic hernia in one case report of Morgagni hernia [61], and contrast swallow was diagnostic on one reported case of Bochdalek hernia [63]. Fluoroscopy Upper GI Series with Small Bowel Follow-Through There is no relevant literature regarding the use of fluoroscopy upper GI series with small bowel follow-through in the evaluation of diaphragmatic hernia. However, demonstration of abnormal bowel configuration suggesting herniation may be helpful in complex cases.


Post Treatment Follow up of Prostate Cancer.  Introduction/Background Prostate cancer is primarily managed by 4 standard treatment methods: radical prostatectomy (RP), radiation therapy (RT), androgen deprivation therapy (ADT), and active surveillance (AS). A detailed discussion of relatively new focal therapies, such as cryotherapy, high-intensity focused ultrasound (US), and MRI-guided ablative techniques are beyond the scope of this document. The treatment choice is based on the tumor stage, histology, and grade and is influenced to a certain extent by the preference of the treating physician and the patient. After treatment, patients are followed at periodic intervals with the measurement of serum prostate- specific antigen (PSA) levels. RP and RT, which includes brachytherapy, are considered definitive treatment therapies. Biochemical recurrence (BCR), also referred to as PSA recurrence, PSA failure, or biochemical failure, is the most clinically used endpoint for identification of treatment failure. A number of clinical nomograms are available to predict BCR, time to metastasis, and prostate cancer-specific mortality [1-3]. Approximately 10% to 53% of patients undergoing primary intended curative therapy will develop BCR, depending on their preoperative disease risk and stage of cancer [4]. For localized low-risk prostate cancer, the rate of BCR is as low as 9% after RP [2,4]. A first serum total PSA assay is recommended during the first 3 to 12 months after RP or RT. When PSA is detectable following RP, a PSA assay should be repeated 1 to 3 months later to confirm this elevation and to estimate the PSA doubling time (PSADT). In the absence of residual or recurrent cancer, PSA becomes undetectable by the first month after total prostatectomy (<0.1 ng/mL) [5]. No imaging study is necessary after definitive treatment for clinically localized prostate cancer before BCR unless there are concerns for complications such as a fistula or abscess [6].


Post Treatment Follow up of Prostate Cancer. Although serum PSA alone does not differentiate local recurrence from distant metastatic disease, the patterns of PSA rise after failed primary therapy have been incorporated into clinical nomograms to predict whether recurrence is more likely local versus distant metastatic disease. Patients with late BCR (>24 months after local treatment), low PSA velocity (change in PSA over time), and/or prolonged PSADT (>6 months) most likely have recurrent local disease [7]. Conversely, patients with a rapid PSA recurrence (<24 months after local treatment), high PSA velocity, or short PSADT (<6 months) are more likely to have metastatic recurrence [7]. This can serve as a clinical guide in selecting the appropriate imaging test to confirm diagnosis. In evaluating patients with recurrent or metastatic prostate cancer, it is important to define the location, size, and extent of local and/or distant tumors. Use of more conventional imaging studies (eg, bone scan and CT) to document recurrent or metastatic disease using clinical parameters is challenging. Choueiri et al [1] demonstrated that with a PSA of <5 ng/mL and a PSADT <10 months, both scintigraphic bone scan and CT are very unlikely to detect the recurrence. The common sites of BCR after failure of definitive management are local recurrence and regional nodal metastasis [8,9]. Although early bone metastases can also be seen, bone metastases are relatively uncommon until later in the course of more advanced metastatic spread when serum PSA values correspondingly tend to also be aNational Cancer Institute, National Institutes of Health, Bethesda, Maryland. bPanel Chair, University of Chicago, Chicago, Illinois. cPanel Vice-Chair, Duke University Medical Center, Durham, North Carolina. dMemorial Sloan Kettering Cancer Center, New York, New York. eMayo Clinic, Jacksonville, Florida. fThe University of Chicago, Chicago, Illinois, Primary care physician. gMayo Clinic, Rochester, Minnesota.


Post Treatment Follow up of Prostate Cancer. hUrology Clinics of North Texas, Dallas, Texas; American Urological Association. iUniversity of Wisconsin, Madison, Wisconsin. jUPMC, Pittsburgh, Pennsylvania; American Urological Association. kSutter Medical Group, Sacramento, California; Commission on Radiation Oncology. lOttawa Hospital Research Institute and the Department of Radiology, The University of Ottawa, Ottawa, Ontario, Canada. mEmory University, Atlanta, Georgia; Commission on Nuclear Medicine and Molecular Imaging. nThe University of Texas MD Anderson Cancer Center, Houston, Texas. oSpecialty Chair, University of Alabama at Birmingham, Birmingham, Alabama. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization. Reprint requests to: publications@acr.org Post-Treatment Follow-up of Prostate Cancer much higher. MRI can identify isolated local recurrences very early, with PSA levels <1 ng/mL [10]. Nodal staging is still a significant diagnostic challenge, because CT and MRI have limited accuracy because of the dependence on size criteria, which is a poor predictor of prostate cancer nodal metastasis. There are currently 4 FDA-approved prostate-specific PET agents for prostate cancer recurrence: 1) carbon-11 choline (C-11 choline), 2) F-18 fluciclovine (also known as anti-1-amino-3-[18-F]-fluorocyclobutane-1-carboxylic acid, [FACBC]), 3) Ga-68-prostate-specific membrane antigen (PSMA)-11, and 4) DCFPyL (2-(3-{1-carboxy-5-[(6-[(18)F]fluoro- pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid). There is a great deal of data for all 4 radiotracers on the performance showing their usefulness for nodal and bone lesion identification.


Post Treatment Follow up of Prostate Cancer. Whole body planar scintigraphic bone scans have historically been frequently performed for detecting skeletal metastases in patients with rising PSA following definitive treatment but are very unlikely to be positive until relatively late in the course of advanced metastatic disease. It was previously thought that a bone scan was quite sensitive, but PET imaging with prostate-specific agents, such as those mentioned above and more sensitive bone agents like fluoride PET, have shown detectability of many lesions before a bone scan becomes positive [11]. Because planar bone scans are rarely positive without symptoms or without relatively high PSA levels, the routine use of this imaging technique at the post-treatment stage is considered ineffective by most investigators [5,12-14] and is not recommended by the National Comprehensive Cancer Network (NCCN). MRI may be helpful in the diagnosis of bone metastasis when other examinations are conflicting, and its combined use with PET imaging can be used to determine response to hormonal treatment [1]. It is notable that prostate cancer is the second leading cause of cancer related mortalities among Americans with prostates. The majority of these patients are not dying because of initial presentation of a high-stage incurable disease. Most of the patients who die from prostate cancer had originally presented with localized disease, underwent definitive primary management with curative intent, experienced treatment failure with BCR, and then their recurrent disease progressed while on nontargeted systemic therapy to become fatal. Recent imaging advances that allow identification of limited metastatic disease early in BCR rather than once the disease has become systemically advanced may hopefully lead to targeted treatments specifically for oligometastatic disease that will impact patient outcomes [18].


Post Treatment Follow up of Prostate Cancer. Finally, it is important to recognize that the clinical scenarios here still represent broad ranges of risk for recurrence or metastases in individuals with prostates. For example, in Variant 1, clinically appropriate imaging may be different for a patient with initially detected BCR and a PSA <1 ng/mL, versus a PSA >40 ng/mL, or for a patient with persistently detectable PSA after surgery. We chose to avoid challenging subcategorizations of many individual patient scenarios encountered in clinical practice, such as by specific PSA ranges or PSA kinetics, or other clinical parameters. It is important to note that in general the yield of the various imaging studies can be related to these additional specific clinical risk parameters. Finally, it should be noted that this document includes analysis of imaging techniques that are formally approved by the FDA. Special Imaging Considerations TRUS Prostatectomy Bed: Drudi et al [19] showed contrast-enhanced color Doppler transrectal US (TRUS) performed as well as contrast-enhanced MRI in detecting local recurrence after prostatectomy; however, intravascular microbubble contrast agents are not FDA approved for this application. Discussion of Procedures by Variant Variant 1: Prostate cancer follow-up. Status post radical prostatectomy. Clinical concern for residual or recurrent disease. Following RP, serum PSA levels are expected to be undetectable within several weeks of surgery. Waiting 6 to 8 weeks after treatment is advisable before assessing the serum PSA value because the half-life of serum PSA is CT Abdomen and Pelvis CT is not effective for detecting recurrent tumors in the surgical bed. The mean PSA value associated with a positive CT scan after RP was 27.4 ng/mL, and this typically represents very large recurrent masses (>2 cm in size) [7].


Post Treatment Follow up of Prostate Cancer. In the evaluation of nodal disease, CT relies on size to detect nodal metastases, which is a significant limitation and confers poor sensitivity for prostate cancer nodal metastases because large numbers of metastatic nodes are known to be a normal size [26]. CT is useful in following the response of known enlarged metastatic lymphadenopathy to treatment. CT is useful in detecting sclerotic bone and visceral metastases, although bone scan and MRI are superior in both the diagnosis and follow-up of bone metastases [27], and choline PET is much better for detection and follow-up of bone metastases. Because bone metastases respond to treatment, they often become more densely sclerotic, which by CT is a common pitfall that can lead to false interpretation as disease progression. CT is useful when done with intravenous (IV) contrast for cancer detection and surveillance. There is no evidence to support use of CT without IV contrast or multiphasic scanning (ie, without and with IV contrast). CT Chest, Abdomen, and Pelvis There is rarely any indication for consideration of extension of coverage with CT of the chest for follow-up of a patient with a clinical concern for residual or recurrent disease, status after RP. Additionally, there is limited evidence to support the use of CT chest abdomen pelvis in this setting. MRI Pelvis Local recurrence seems to be a common site of initial disease recurrence, and MP-MRI is the most accurate imaging method for identifying sites of local recurrence after RP [6,28-32]. It is worth noting that, unlike with the Prostate Imaging Reporting and Data System (PI-RADS) applied to pretreatment imaging, there are no consensus technical standard or interpretation criteria for MRI in the BCR setting. In general, 3.0T performs better than 1.5T, and endorectal coil use can offer an improved signal-to-noise ratio and resolution to aid in detecting small early recurrences compared to surface coils.


Post Treatment Follow up of Prostate Cancer. Recurrences can be accurately identified very early in BCR at the time of initial laboratory diagnosis of BCR when the PSA is still well under 1 ng/mL [10]. Although most local recurrences are perianastomotic, retrovesical, or in the seminal vesicle bed, 30% may be elsewhere in the pelvis at sites that can be more readily assessed by MRI than by US [32]. MP-MRI studies for detecting local recurrence after prostatectomy have reported 84% to 100% sensitivity and 89% to 97% specificity [6,10,33]. Typically, in this setting, MRI of the pelvis only is performed, at least initially. Residual, recurrent, or metastatic disease are all most likely to be identified in the pelvis, and additional coverage of the abdomen is of little added value. Post-Treatment Follow-up of Prostate Cancer The accuracy of MRI for staging pelvic lymph nodes, similar to CT, is largely reliant on size criteria and is only minimally better than that of CT. MRI is more sensitive and specific in the diagnosis of bone metastases, with a much better spatial and contrast resolution when compared to scintigraphic bone scan [34,35]. Gutzeit et al [36] reported the use of whole body diffusion-weighted imaging (DWI)-MRI in 36 patients with 45 skeletal metastases from breast cancer and prostate cancer and concluded that markedly more metastases could be discovered using the whole body DWI technique than skeletal scintigraphy. Response of bone metastases to treatment can be more accurately monitored by serial MRI scans [37]. MRI has a similar performance in bone metastasis detection as choline PET [8]. Overall, pelvic MRI in the setting of Variant 1 is complementary to specialized PET examinations (choline or fluciclovine), and both categories of examinations may be beneficial to perform.


Post Treatment Follow up of Prostate Cancer. MRI Functional and Multiparametric: Traditional T1- and T2-weighted MRI sequences can be supplemented with functional techniques: dynamic contrast-enhanced MRI (DCE-MRI) imaging, DWI-MRI including apparent diffusion coefficient map and high b value DWI-MRI (preferentially b >1400 sec/mm2). When these 2 are added to anatomic T2 and T2-weighted MRI, the term MP-MRI is often applied. These will be briefly discussed, but a detailed explanation of these techniques is beyond the scope of this document. In summary, all 3 have shown some evidence of incremental value when added to anatomic imaging (T2-weighted), and there is evidence that use of more than 1 functional technique can also be additive and complementary. Among the 3, DCE-MRI has the strongest evidence and has consistently shown the greatest use in the setting of BCR evaluation. DCE-MRI: DCE-MRI has been shown to be the most important sequence for evaluation of BCR post-RP [38]. Wu et al [39] in a meta-analysis to assess the effectiveness of MRI in detecting local recurrent prostate cancer after RP found that DCE-MRI, compared to T2-weighted imaging, showed a higher pooled sensitivity (85%) and specificity (95%). Roy et al [38] evaluated the performance of the 3 types of functional MRI techniques in the detection of local prostate cancer recurrence after RP and concluded DCE-MRI to be the most efficient tool to detect prostate cancer recurrence post-RP. Similarly, Casciani et al [30] and Cirillo et al [6] showed that DCE- MRI had a significantly higher sensitivity and accuracy than T2-weighted imaging alone in detecting local recurrences after RP. DWI-MRI: DWI-MRI can be helpful for local recurrence depiction, but DWI is typically lower in resolution and more often adversely affected by postoperative changes and surgical clip artifacts than DCE, making it less reliable for local recurrence. A combination of these functional sequences can be more accurate to evaluate for recurrence in the postprostatectomy bed [33].


Post Treatment Follow up of Prostate Cancer. DWI is helpful for detection of nodal and bone metastases and can be performed as a whole body screening examination [40]. However, the restricted diffusion at DWI can be nonspecific and can also be observed in normal sized or hyperplastic benign lymph nodes. MRI Abdomen and Pelvis In this setting, MRI of the pelvis only is performed, at least initially. Residual, recurrent, or metastatic disease are all most likely to be identified in the pelvis, and additional coverage of the abdomen is of little added value. Additionally, there is limited evidence to support the use of MRI abdomen and pelvis for follow-up of a patient with a clinical concern for residual or recurrent disease, status post-RP. TRUS-Guided Biopsy Prostatectomy Bed TRUS-guided biopsy can be performed in a systematic manner, often done as a random sampling of the areas that most likely harbor recurrence: the vesicourethral anastomosis, retrovesical region, and seminal vesicle beds. Negative results of TRUS-guided biopsy, regardless of a palpable mass or indurations, may be inconclusive because of sampling errors. Deliveliotis et al [41] reported negative predictive values of only 67% with TRUS- guided biopsy and 57% with digital rectal examination (DRE)-guided biopsy in patients with PSA >2 ng/mL and negative imaging for metastases after prostatectomy. The yield for detecting local recurrent tumor with TRUS with needle biopsy rises significantly with serum PSA levels [41]. Only about 25% of patients with prostatectomy PSA levels of <1 ng/mL have a histologic confirmation of local recurrence after systematic biopsy of the prostatic fossa, compared with 53% of patients with prostatectomy PSA levels >2 ng/mL [41].


Post Treatment Follow up of Prostate Cancer. MRI-Targeted Biopsy Prostatectomy Bed Similar to the greatly increased yields of targeted biopsy informed by targets identified on MRI in initial prostate cancer detection, biopsy in the setting of BCR is much more likely to identify a local recurrence when done targeting a suspicious lesion identified by MRI rather than systematic biopsy of the operative bed. In this setting, Post-Treatment Follow-up of Prostate Cancer it is the prostatectomy bed rather than the prostate itself. Because there is no commercial targeting application available in the postprostatectomy setting (there is no gland to segment), these targeted biopsies must be done with cognitive fusion or in-bore targeting [10]. Candidacy for salvage local therapy is largely determined by identification and characterization of a treatable local recurrence by biopsy. TRUS Prostatectomy Bed Several studies have shown the usefulness of color and power Doppler and contrast-enhanced color Doppler in detecting local recurrence after prostatectomy [19,42,43]. Choline PET/MRI Skull base to Mid-Thigh PET/MRI is a relatively newer imaging modality that allows simultaneous anatomic, functional, and molecular imaging of body parts. Few studies have evaluated the use of choline in PET/MRI. In 1 study with 75 patients with BCR, choline PET/MRI had a higher cancer detection rate compared with choline PET/CT (84.7% versus 77.3%) [58]. Fluciclovine PET/CT Skull Base to Mid-Thigh Fluciclovine (also known as anti-1-amino-3-[18-F]-fluorocyclobutane-1-carboxylic acid [FACBC]) is a synthetic amino acid PET radiotracer that was FDA approved in May 2016 for the imaging of patients with suspected prostate cancer recurrence based on elevated serum PSA levels following prior treatment. Odewole et al [59] reported superiority to 111 indium-capromab pendetide and to CT with detection of nodes as small as 5 mm and upstaging 25.7% of patients.


Post Treatment Follow up of Prostate Cancer. In comparison to CT, the fluciclovine PET positivity rate for recurrent disease was 77.4% versus 18.9%, although sensitivity varies with PSA level, PSADT, and original Gleason Score [59]. One- hundred patients with biochemical failure after RP underwent choline PET and fluciclovine PET in a single-center trial [60-62]. The investigators reported choline and fluciclovine had overall sensitivities of 32% and 37%, specificities of 40% and 67%, and positive predictive values of 90% and 97%, respectively, with fluciclovine having a lower physiologic background, resulting in better lesion contrast, and the practical advantage of a longer half-life enabling more widespread distribution compared with a short half-life C-11 radiotracer. Notably, in this single-center comparison from Italy, the C-11 choline dose used was only about one-third of that used for most patients imaged clinically with choline in the United States, and the performance of both agents reported was much lower than that of many other studies, with the meta-analysis of choline showing a sensitivity of 85.6% and a specificity of 92.6% for all sites of recurrence, and a meta-analysis of fluciclovine that reported an 87% pooled Fluciclovine PET/MRI Skull Base to Mid-Thigh There is limited evidence to support the use of fluciclovine PET/MRI for the follow-up of a patient with a clinical concern for residual or recurrent disease, status post-RP. PET Using Other Agents: There are many additional prostate-specific tracers that are not FDA approved, including 11C-acetate [70,71], 18F-choline [72-75], Bombesin, and 18F-fluorodihydrotestosterone [76-78], that are in various stages of investigation and have been reported to detect local and metastatic recurrent disease in patients with biochemical failure after local treatment. These agents remain investigational, but some have shown excellent results and hold great potential.