Pretreatment Evaluation and Follow Up of Endometrial Cancer. Initial Staging EC is the most common gynecologic malignancy in the United States, with approximately 61,880 newly diagnosed cases and 12,160 deaths expected in 2019 [1]. Histopathologically, ECs are classified as type I (>80%) and type II (<20%) [2]. Type I tumors are typically endometrioid in histology and estrogen-dependent. They are often low- grade (grade 1 and 2) preceded by a premalignant endometrial hyperplasia and are associated with a better prognosis. Type II tumors tend to be nonestrogen dependent, nonendometrioid, high-grade endometrioid tumors (grade 3), and characteristically arise from an atrophic endometrium. They demonstrate a worse prognosis and are responsible for almost half of the EC-related deaths [3].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Patients with EC typically present with stage I disease (80% of cases), and the recommended treatment is complete resection of disease by hysterectomy and bilateral salpingo-oophorectomy. Multiple studies have demonstrated that recurrence risk after treatment is related to the depth of myometrial invasion, tumor grade, histological subtype, and


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Reprint requests to: publications@acr.org


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Evaluation and Follow-Up of Endometrial Cancer lymphovascular space invasion in clinically proven stage I [7]. Risk stratification systems that aggregate these prognostic factors to define recurrence risk groups have been developed and are now used worldwide to guide decision-making and design clinical trials [2,8-10]. Results of a 2014 study of a simultaneous comparison of several proposed risk stratification systems suggested that the European Society for Medical Oncology modified system was the most accurate in the prediction of lymph node status and survival [10]. In that system, categorization of risk grouping was based on FIGO stage, tumor grade, histological subtype, and lymphovascular space invasion. Patients with disease of FIGO stage IB grade 3 endometrioid type with positive lymphovascular space invasion or nonendometrioid histology of all stages can be classified as high risk. Conversely, patients with FIGO stage IA with grade 1 to 2 EC and no lymphovascular space invasion can be classified as low risk. All other tumors can be classified as intermediate or high-intermediate risk. This risk stratification system also guides the need and extent of lymph node sampling for initial staging [9].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Surveillance and Posttherapy Evaluation EC tends to recur in the pelvis, especially in the vaginal vault (42% of recurrences) and pelvic lymph nodes, followed by para-aortic lymph nodes [16]. Extrapelvic recurrence commonly involves the peritoneum and lungs. Atypical metastatic sites include extra-abdominal lymph nodes, liver, adrenals, brain, bones, and soft-tissue [17]. Therefore, posttherapy surveillance imaging may include evaluation of the abdomen and pelvis. Imaging of the chest may be indicated in selected high-risk, advanced stage patients to detect lung metastasis.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Close follow-up after the completion of treatment for EC is suggested, particularly in the first 3 years after diagnosis, when the risk of recurrence is highest [18]. This usually includes a history and physical examination every 3 to 6 months for several years. Vaginal bleeding is a common symptom of local recurrence. In patients with a distant recurrence, symptoms such as coughing, pain, lethargy, weight loss, or headaches are present in up to 70% of cases [19,20]. In one study, a combination of findings at physical examination with or without patient symptomatology, resulted in a >80% recurrence detection rate [21]. Radiologic evaluation such as a CT scan or fluorine-18-2-fluoro- 2-deoxy-D-glucose (FDG)-PET/CT scan of the chest, abdomen, and pelvis should only be used to investigate suspicion of recurrent disease and not for routine surveillance after treatment [22]. Whenever feasible, pathologic diagnosis with biopsy should be done to confirm disease recurrence [23].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Special Imaging Considerations MR perfusion and blood oxygen level dependent MRI do not have established roles in the evaluation of EC [24].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Evaluation and Follow-Up of Endometrial Cancer Certain ECs have demonstrated increased spectroscopic signals from choline, lipids, and lactates [24]. This reaction could be exploited to determine long-term prognosis and treatment response on MR spectroscopy but still needs validation. Magnetic iron oxide nanoparticles or ultra-small particles of iron oxides may demonstrate a potential in detecting malignant pelvic lymph nodes, but these particles are not widely available [25].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Contrast-enhanced US could be useful to diagnose the depth of myometrial invasion using the arcuate vascular plexus involvement as a marker, with the diagnostic accuracy for determining the myometrium infiltration depth was 85.3%; however, this needs further validation [31].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. FDG-PET/MRI is emerging as a hybrid imaging modality that combines the functional ability of PET with the morphological high soft-tissue contrast provided by MRI. Although there is a paucity of literature on the role of FDG-PET/MRI for the initial staging and suspected recurrence in patients with EC, studies assessing local staging, lymph node involvement, and distant metastases in gynecological malignancies have found that FDG-PET/MRI is equivalent or outperforms FDG-PET/CT. Queiroz et al [32] studied 26 patients with gynecological malignancies (including four ECs) and found that PET/MRI had improved delineation compared to PET/CT for 2 of 3 ECs and 6 of 7 cervical cancers. These authors found no difference in the detection of regional lymph node involvement and abdominal metastases between the two modalities. More recently, a meta-analysis that comprised 7 studies and 216 patients with a variety of gynecological malignancies showed excellent diagnostic performance of FDG-PET/MRI to assess the primary tumor, nodal staging, and recurrence in patients with gynecological malignancies including EC [33]. In a study of 81 patients with proven recurrence of gynecological malignancy, PET/MRI achieved a lesion- based accuracy of 94% compared to 92% for PET/CT [34]. A meta-analysis (7 studies, 257 patients, 695 lesions) that evaluated the diagnostic value of FDG-PET/MRI for restaging patients with suspected recurrence of gynecological malignancies reported the pooled sensitivity and specificity on a patient-based analysis to be 0.96 and 0.95, respectively, and on a lesion-based analysis 0.99 and 0.94, respectively [35].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Discussion of Procedures by Variant Variant 1: Initial staging of pretreatment endometrial cancer; assessment of local tumor extension for all tumor grades. Currently there is little consensus on the role of pelvic imaging in the preoperative staging of EC, with practices differing widely across centers [36]. However, when assessment of local tumour extent during initial staging is clinically indicated, this variant addresses the evidence regarding the appropriate use of the different imaging modalities. The NCCN 2020 guidelines advise MRI for initial workup as follows: to establish the origin of the tumor (endocervical versus endometrial), assess local disease extent, and exclude myometrial invasion for fertility sparing treatment [23]. In 2016, a European multidisciplinary expert panel consensus meeting on EC suggested that MRI may be useful to assess myometrial invasion in centers in which the need for lymph node dissection is based on the preoperative stratification into low-, intermediate-, or high-risk groups [37].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Preoperative risk stratification is important, because currently there is no imaging modality that can replace surgical staging, given the inability of preoperative imaging to identify small lymph node metastases, which if present will require adjuvant therapy. However, MRI is accurate at identifying two surrogate markers of lymph node metastases (eg, deep myometrial invasion and cervical stromal involvement) [38]. In the absence of these and with low-grade tumors, the risk of lymph node metastases is low [39]. In the presence of these surrogate markers, the likelihood of lymph node metastases is high enough for full surgical staging by gynecological surgeons even for low-grade tumors [9]. The role of sentinel lymph node sampling versus complete lymphadenectomy in this subgroup of patients requires further investigation [13].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. High-grade tumors are at risk for extrauterine spread and therefore warrant full surgical staging by gynecological surgeons. The role of imaging in this subgroup may be to identify extrauterine metastases or spread, which helps


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Evaluation and Follow-Up of Endometrial Cancer plan the surgical approach (eg, minimally invasive surgery versus laparotomy). Laparotomy is the preferred approach when involvement of pelvic or abdominal organs are suspected.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. MRI Pelvis Pelvic MRI has long been established as a valuable imaging method in the preoperative staging of EC [45-49]. MRI is preferred over US or CT for pretreatment evaluation because it allows the most accurate evaluation of the extent of pelvic tumor. A meta-analysis showed that the efficacy of contrast-enhanced MRI is significantly better than that of noncontrast MRI and US, and tended toward better results than CT, in evaluating the depth of myometrial invasion in patients with EC [50]. One study found that high-frequency TVUS has similar diagnostic accuracy in the evaluation of both tumor extension into the cervix (92% for high-frequency TVUS versus 85% for MRI) and myometrial invasion (84% for high-frequency TVUS versus 82% for MRI) [51]. However, in patients with an elevated body mass index, in the presence of myomas or adenomyosis, in the setting of bulky tumors, and in the presence of a vertical or retroverted uterine corpus, evaluation of the EC is difficult with TVUS [51].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Disruption of the low signal intensity junctional zone on the T2-weighted images (T2WI) indicates the presence of myometrial invasion. Deep myometrial invasion is diagnosed when the intermediate signal intensity of the tumor involves at least 50% of the myometrial thickness on the T2WI. Dynamic contrast-enhanced MRI performs significantly better than unenhanced MRI for evaluating the depth of myometrial invasion, which is best demonstrated after 50 to 120 seconds postcontrast injection [50,52]. Inner layers of the junctional zone typically enhance on arterial phase [24]. Demonstration of an undisrupted enhancing subendometrial line signifies lack of myometrial involvement [24]. This is a useful sign to rule-out myometrial invasion in postmenopausal patients whose junctional zone is otherwise not well discernible on T2WI [53]. In addition, absence of myometrial invasion as shown by an intact subendometrial line of enhancement is particularly relevant for women wishing to consider fertility-preserving treatment options.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. EC shows restricted diffusion and appears hyperintense on DWI relative to surrounding myometrium. One study showed that the apparent diffusion coefficient (ADC) value of the peritumoral tissue achieved an accuracy similar to the qualitative assessment by experienced readers, 83% versus 76%, respectively [54]. A meta-analysis revealed that the pooled sensitivity and specificity of DWI for detecting deep myometrial invasion were 80.9% and 85.9%, respectively [55]. It was also reported that the diagnostic capability of DWI for deep myometrial invasion improved when it was combined with T2WI (pooled sensitivity: 85.8%, pooled specificity: 94.7%). These results are comparable or superior to the contrast-enhanced MRI, thus DWI can be a potential alternative to patients with compromised kidney functions, in which contrast is contraindicated [46,47,56-61]. An erroneous MRI assessment in evaluating the depth of myometrial invasion can sometimes be caused by a polypoid tumor compressing the myometrium or in the presence of adenomyosis and leiomyomas.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Evaluation and Follow-Up of Endometrial Cancer


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Studies have not shown any added advantage of using 3T versus 1.5T, and results are comparable for both 3T and 1.5T systems. Advantages of 3T imaging includes improved spectral separation as well as increased signal-to-noise ratios, which can be exploited to acquire images with a higher spatial resolution or decreased image acquisition times. However, 3T images typically have more susceptibility and chemical shift artifacts and greater image inhomogeneity on T2WI [67,68].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Pelvis Transvaginal In a study of 169 consecutive patients with EC, TVUS achieved a 79.5% sensitivity and a 89.6% specificity for detecting deep myometrial invasion were 82% and 81%, respectively [69]. A prospective collaborative trial comparing MRI and US, reported that the accuracy of US is comparable to that provided by MRI [51]. However, US has reported accuracies varying between 77% and 91% [50,51]. A more recent study found that MRI showed greater accuracy than 3-D TVUS or 2-D TVUS (83%, 71%, and 75%, respectively) for myometrial involvement [28]. US is limited in the setting of concomitant benign disease (eg, leiomyomas or adenomyosis) and also for large lesions because of the limited depth of penetration of TVUS. In addition, there are insufficient reports about the benefit of TVUS in predicting cervical extension, parametrical invasion, or lymphadenopathy. Studies have shown that contrast-enhanced US could be useful to diagnose the depth of myometrial invasion using the arcuate vascular plexus involvement as a marker; however, this needs further validation [31].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Variant 2: Pretreatment evaluation of endometrial cancer; assessment of lymph node and distant metastasis for low-grade tumor (Type I, grade 1, 2). Most patients with low-grade disease are at low risk of lymph node and distant metastases. In the largest series to date on grade 1 ECs, the incidence of pelvic lymph node involvement, pelvic metastasis, and distant metastasis specific to grade 1 tumors is estimated at 3.3%, 4.6%, and 2.4%, respectively [70].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. CT Chest, Abdomen, and Pelvis Contrast-enhanced CT of the abdomen and pelvis may be employed preoperatively for the detection of lymph node metastases in EC. However, the reported sensitivity of contrast-enhanced CT for pelvic and para-aortic lymphadenopathy is only 29% to 52% [71,72]. If distant metastatic disease is clinically suspected, preoperative assessment of metastatic disease with contrast-enhanced CT is indicated. However, most patients with low-grade disease are at low risk of lymph node and distant metastases. Thus, this group does not require a routine pretreatment evaluation for distant metastases by CT imaging.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. FDG-PET/CT Skull Base to Mid-Thigh The role of PET in EC imaging is evolving. Recently, a meta-analysis reported that the overall pooled sensitivity, specificity, and accuracy of using FDG-PET/CT for detection of lymph node metastasis in EC was 72.0%, 94.0%, and 88.0%, respectively [73]. Although this meta-analysis found the overall sensitivity of FDG-PET/CT to be moderate for the detection of lymph node metastasis in EC, it compares favorably with the reported sensitivities for lymph node metastasis detection by conventional MRI and CT. However, because 45% of ECs are grade 1 and not particularly FDG-avid, the routine use of FDG-PET in preoperative staging in early stage disease is not recommended, but FDG-PET may be used in patients in which distant metastases is clinically suspected [19,74].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Lymphangiography Pelvis Lymphangiography pelvis is not helpful for evaluating cancer of the endometrium because 1) it is invasive, and 2) its performance for assessing pelvic lymph nodes is not reproducible and the accuracy is slightly inferior to that of CT and MRI [75].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. MRI Abdomen If distant metastasis to other abdominal organs (eg, liver) is clinically suspected, abdominal MRI or CT may be performed. However, patients in this group are at low risk for distant metastases [80].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Pelvis Transabdominal The combination of morphological and vascular patterns of lymph nodes using transabdominal US can be used to differentiate metastatic from normal or reactive nodes [81]. However, visualization of retroperitoneal or iliac lymph nodes can be limited using US because of patient body habitus and overlying bowel gas. Suspicious inguinal lymph nodes can be readily assessed by US and biopsied as needed.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Abdomen Transabdominal US can be used to detect abdominal organ metastasis. However, most patients with low-grade disease are at low risk of lymph node and distant metastases and thus may not require routine pretreatment evaluation by US imaging.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Variant 3: Initial staging of pretreatment endometrial cancer; assessment of lymph node and distant metastasis for high-grade tumor (Type I, grade 3 and Type II). In a recent series, nodal metastases have been depicted in up to 29% of patients in intermediate- to high-risk categories [82]. In a study of 55 patients with EC with distant metastasis, 47.2% of patients had a type II tumor [83]. CT Chest, Abdomen, and Pelvis Contrast-enhanced CT of the abdomen and pelvis may be employed preoperatively for the detection of lymph node metastases in this group. However, the reported sensitivity of contrast-enhanced CT for pelvic and para-aortic lymphadenopathy is only 30% to 57%; meanwhile, the reported specificity of contrast-enhanced CT is 92% to 98% [41,71,72]. If distant metastatic disease is clinically suspected, preoperative assessment of metastatic disease with contrast-enhanced CT is indicated [37].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Lymphangiography Pelvis Lymphangiography pelvis is not recommended for evaluating cancer of the endometrium because 1) it is invasive, and 2) its performance for assessing pelvic lymph nodes is not reproducible and the accuracy is slightly inferior to that of CT and MRI even when performed optimally [75].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. MRI Abdomen If distant metastasis to other abdominal organs (eg, liver) is clinically suspected, abdominal MRI or CT may be performed.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Pelvis Transabdominal The combination of morphological and vascular patterns of lymph nodes using transabdominal US can be used to differentiate metastatic from normal or reactive nodes [81]. However, there is insufficient data to allow comparison of this procedure to CT or MRI. Nevertheless, visualization of retroperitoneal or iliac lymph nodes is frequently limited using US because of patient body habitus and overlying bowel gas. Suspicious inguinal lymph nodes can be readily assessed by US and biopsied as needed.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Abdomen If solid abdominal organ metastatic disease is clinically suspected, then transabdominal US may be used [81].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Variant 4: Surveillance of asymptomatic patients with treated low- or intermediate-risk endometrial cancer. Recurrence rates for low- or intermediate-risk patients with EC are infrequent. Therefore, a recent review of posttreatment surveillance and diagnosis of recurrence in women with gynecologic cancers sponsored by the Society of Gynecologic Oncology recommends that radiologic evaluation be used only to investigate suspicion of recurrent disease because of symptoms or physical exam and not for routine surveillance after treatment [80].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. MRI Pelvis There currently is not sufficient evidence in the literature to recommend routine surveillance by MRI for patients with low- or intermediate-risk EC [80].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. MRI Abdomen MRI may also be used for assessment of metastasis of the liver, adrenals, brain, bones, and soft-tissue when metastases are clinically suspected and need further investigation. However, there is insufficient data to support the routine use of MRI for surveillance of asymptomatic patients [80].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. CT Chest, Abdomen, and Pelvis A review of the literature found that only 5% to 21% of asymptomatic recurrences were detected by CT [87]. Another study reported that the role of CT scanning for asymptomatic patients is not warranted because survival of patients with disease that is detected on CT scan, compared with clinical examination, did not differ significantly [88]. Therefore, the use of routine CT scan is not useful for disease surveillance [19,89].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Radiography Chest Chest radiographs have been advocated for the detection of asymptomatic chest recurrences, often on a semi-annual or annual basis. However, the rate of detection for asymptomatic chest recurrences found on chest radiographs ranges only from 0% to 20% [87,90]. Thus, this procedure may not be appropriate for this group.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Pelvis Transvaginal Because many of the recurrences are detected during the physical examination, the use of routine pelvic US is not advocated [21,87].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Pelvis Transabdominal Because many of the recurrences are detected during the physical examination, the use of routine pelvic US is not advocated [21,87].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Abdomen Because many of the recurrences are detected during the physical examination the use of abdominal US is not advocated [21,87].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Evaluation and Follow-Up of Endometrial Cancer Variant 5: Surveillance of asymptomatic patients with treated high-risk endometrial cancer. Most patients are cured following primary treatment; however, approximately 25% to 30% of patients in this subgroup may develop recurrent disease [91]. Typical metastatic sites of recurrent EC are local pelvic recurrence, pelvic and para-aortic lymph nodes, peritoneum, and lungs [17]. Atypical metastatic sites are extra-abdominal lymph nodes, liver, adrenals, brain, bones, and soft-tissue [17]. Vaginal bleeding is a common symptom of a local recurrence. In patients diagnosed with a distant recurrence, symptoms such as coughing, pain, lethargy, weight loss, or headaches are present in up to 70% of cases [19,20]. In one reported study, the combination of physical examination alone or in combination with symptoms resulted in detection rates of recurrence that exceeded 80% [21].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. CT Chest, Abdomen, and Pelvis The evidence supporting routine CT surveillance following EC is insufficient. Even in type II EC, CT scans detected only 15% of recurrences [92]. Chest CT with or without intravenous (IV) contrast may be obtained as a part of posttherapy surveillance in selected high-risk groups or patients with an advanced FIGO stage [81,83,84].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. MRI Pelvis Recurrent tumor appears as a mass with high signal intensity on T2WI and intensely enhances following IV contrast administration [93]. MRI has a role in the evaluation of surgical resectability if the pelvis is the sole site of recurrence [36]. However, there is insufficient data to support the routine use of MRI for surveillance of asymptomatic patients [80].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Radiography Chest Chest radiographs have been advocated for the detection of asymptomatic chest recurrences, often on a semi-annual or annual basis. However, the rate of detection for asymptomatic chest recurrences found on chest radiographs ranges only from 0% to 20% [87,90]. Thus, this procedure may be useful when lung metastases are clinically suspected.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Pelvis Transvaginal Because many of the recurrences are detected during physical examination, the use of routine pelvic is not advocated [21,87].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Abdomen Because many of the recurrences are detected during the physical examination, the use of abdominal US is not advocated [21,87].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Variant 6: Posttherapy evaluation of clinically suspected recurrence of known endometrial cancer. Most patients are cured following primary treatment, and approximately 25% to 30% of patients with high-risk EC may develop recurrent disease [91]. Typical metastatic sites of recurrent EC are local pelvic recurrence, pelvic and para-aortic nodes, peritoneum, and lungs [17]. Atypical metastatic sites are extra-abdominal lymph nodes, liver, adrenals, brain, bones, and soft-tissue [17]. Vaginal bleeding is a common symptom of a local recurrence. In patients diagnosed with a distant recurrence, symptoms such as coughing, pain, lethargy, weight loss, or headaches are present in up to 70% of cases [19,20]. In one reported study, the combination of physical examination alone or in combination with symptoms resulted in detection rates of recurrence that exceeded 80% [21].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. MRI Pelvis MRI may be indicated in a patient clinically suspected to have local recurrence or distant metastasis [94]. Recurrent tumor appears as a mass with high signal intensity on T2WI and enhances intensely following IV contrast administration [93]. MRI has a role in the evaluation of surgical resectability if the pelvis is the sole site of recurrence [36,95].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Evaluation and Follow-Up of Endometrial Cancer MRI Abdomen MRI may be indicated in patient clinically suspected to have local recurrence or distant metastasis [94]. Recurrent tumor appears as a mass with high signal intensity on T2WI and enhances intensely following IV contrast administration [93]. MRI may be used for assessment of metastasis of the liver, adrenals, brain, bones, and soft tissue when metastases are clinically suspected and require further investigation.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. CT Chest, Abdomen, and Pelvis CT may play a role in the evaluation of patients with symptoms suggestive of recurrence [71]. A study reported that 45 asymptomatic women had routine CT scans, and recurrence was diagnosed by CT in only 2 (4.4%); whereas, 37 symptomatic women had CT scans for suspicion of recurrence, and it was confirmed by CT in 17 (46%) [71].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. FDG-PET/CT Skull Base to Mid-Thigh A recent meta-analysis with over 500 patients showed a sensitivity of 95.8% and specificity of 92.5% with FDG- PET or FDG-PET/CT in detecting recurrent EC [96]. Another study showed that in the detection of recurrence and the evaluation of treatment response, FDG-PET, implemented by CT or MRI, performed better (sensitivity 100%, specificity 88.2%, accuracy 93.3%) than CT or MRI alone (sensitivity 84.6%, specificity 85.7%, accuracy 85%) and tumor markers (eg, CA125, CA19-9, CEA, and sialyl TN antigen; sensitivity 100%, specificity 70.6%, accuracy 83.3%) [97].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Pelvis Transvaginal Detection rates for local recurrence using pelvic US scans range from 4% to 31%. Many of these recurrences, however, were also detected using other diagnostic methods, including physical examination [21,80,87].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Pelvis Transabdominal Detection rates for local recurrence using pelvic US scans range from 4% to 31%. Many of these recurrences, however, were also detected using other diagnostic methods, including physical examination [21,80,87].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. US Abdomen If abdominal organ metastatic disease is clinically suspected, then transabdominal US can be used [81].


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and rating round tabulations for each recommendation.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Penetrating Trauma Lower Abdomen and Pelvis. Most of the contemporary literature concerning urethral injury deals with posterior urethral injuries associated with pelvic fractures, which are most commonly due to motor vehicle accidents [4]. In male patients with suspected penetrating trauma of the urethra, the anterior urethra is most often affected. Penetrating injury to the anterior urethra is typically surgically repaired in the acute setting [1,2]. Evaluating the degree of disruption of the anterior urethra is an important factor in operative planning. Penetrating posterior urethral injury is treated with immediate exploration via a retropubic approach and primary repair; if coexisting severe injuries preclude direct urethral repair initially, suprapubic diversion with delayed urethroplasty can be performed [1]. Retrograde urethrography (RUG) has traditionally been the standard diagnostic imaging method for evaluation of urethral trauma endorsed by the EAU and AUA [1-3]. Penetrating trauma of the female urethra is uncommon because of its anatomy and is typically diagnosed with urethroscopy [1].


Penetrating Trauma Lower Abdomen and Pelvis. aUniversity of Pittsburgh, Pittsburgh, Pennsylvania. 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. fMcGill University, Montreal, Quebec, Canada. gMayo Clinic, Rochester, Minnesota. hUrology Clinics of North Texas, Dallas, Texas; American Urological Association. iMaine Medical Center, Portland, Maine; American College of Emergency Physicians. jUPMC, Pittsburgh, Pennsylvania; American Urological Association. kCleveland Clinic, Cleveland, Ohio. lStanford University Medical Center, Stanford, California. mOttawa Hospital Research Institute and the Department of Radiology, The University of Ottawa, Ottawa, Ontario, Canada. nNational Institutes of Health, Bethesda, Maryland. oThe University of Texas MD Anderson Cancer Center, Houston, Texas. pUniversity of Washington, Seattle Cancer Care Alliance, Seattle, Washington. qSpecialty Chair, University of Alabama at Birmingham, Birmingham, Alabama.


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


Penetrating Trauma Lower Abdomen and Pelvis. Reprint requests to: publications@acr.org


Penetrating Trauma Lower Abdomen and Pelvis. Types III and IV bladder injuries can be the result of penetrating pelvic injury. Extraperitoneal rupture represents approximately 60% of major bladder injuries that are due to blunt trauma [3,6]; the incidence of extraperitoneal versus intraperitoneal rupture that is due to penetrating bladder trauma is not known. Sandler et al [7] further subdivided extraperitoneal rupture into 2 groups. With simple extraperitoneal rupture, contrast extravasation is limited to the pelvic extraperitoneal space. With complex extraperitoneal rupture, contrast material extravasation may extend into the anterior abdominal wall, the penis, the scrotum, and the perineum. The presence of a complex extraperitoneal injury implies that the injury has disrupted the fascial boundaries of the pelvis. Such findings should not be mistaken as evidence of a coexisting urethral injury. A combined bladder injury (type IV) results when both intraperitoneal and extraperitoneal bladder injuries are present. Penetrating bladder injuries are typically repaired surgically in the acute setting unless coexisting life-threatening injuries are present [1].


Penetrating Trauma Lower Abdomen and Pelvis. orifice Urethral Injury Injuries to the male urethra have been traditionally classified into 2 main categories according to their mechanism of injury: 1) those associated with a fracture of the anterior pelvic arch (usually involving the membranous urethra) and 2) those occurring as the result of a straddle injury (usually involving the bulbous urethra); both of these types of male urethral injury are more commonly found after blunt trauma, but can also result from penetrating trauma. The penile urethra is injured less frequently than the bulbar and membranous segments of the urethra overall; however, the penile urethra is more commonly injured with penetrating trauma because of its entirely external location.


Penetrating Trauma Lower Abdomen and Pelvis. Female urethral injuries are rare and are usually associated with pelvic fracture or vaginal laceration [2,9,11]. The rarity of female urethral injury is due to the relatively shorter length, internal location posterior to the osseous


Penetrating Trauma Lower Abdomen and Pelvis. Discussion of Procedures by Variant Variant 1: Penetrating trauma, lower abdomen and pelvis. Suspected lower urinary tract trauma. Initial imaging. Radiography Pelvis There is no relevant literature regarding the use of radiographs in the evaluation of penetrating trauma to the lower urinary tract. Radiography of the pelvis plays an ancillary role by identifying radiopaque foreign bodies associated with penetrating injuries and in identifying pelvic fractures. Pelvic radiography can be combined with RUG.


Penetrating Trauma Lower Abdomen and Pelvis. CT Pelvis with Bladder Contrast (CT Cystography) Schneider [12] stated that either retrograde cystography or CT is the diagnostic procedure of choice for a suspected bladder injury, and Horstman et al [13] found that both types of imaging examinations equally detected all types of bladder injury in blunt trauma patients. The authors indicated that contrast instillation during CT can provide the adequate bladder distention needed to demonstrate contrast extravasation from the injury site. Since then, CT cystography has become the first-line evaluation for bladder injury in the acute trauma setting [4]. This technique refers to the retrograde instillation of a minimum of 350 cc of diluted contrast media into the bladder, followed by axial and coronal CT images of the pelvis [6,14]. Unlike conventional cystography, no postdrainage CT images are needed. In a study that included patients who sustained blunt and penetrating trauma, there was 100% sensitivity and 99% specificity for intraperitoneal bladder rupture; additionally, the specific site of bladder dome injury was found in 4 of the 18 patients and was identified only with multiplanar reconstructed images [14]. An advantage of CT cystography is the ability to diagnose injuries to other pelvic viscera, osseous structures, and vasculature.


Penetrating Trauma Lower Abdomen and Pelvis. Contrast-enhanced CT with excretory phase imaging is not a reliable means to diagnose bladder rupture, even after a urethral catheter has been inserted and clamped [2,15,16]. Excretory phase imaging is defined as antegrade filling of the urinary bladder that is due to excretion of intravenous (IV) contrast material through the kidneys. Although intraperitoneal and extraperitoneal fluid can be detected during excretory phase CT, the etiology of the fluid cannot be determined because the bladder is usually inadequately distended to cause extravasation through a bladder laceration or perforation. Although the absence of pelvic fluid is strong evidence against a bladder rupture, a negative study does not exclude bladder injury [17].


Penetrating Trauma Lower Abdomen and Pelvis. The literature suggests that both conventional and CT cystography are equivalent, with physician preference and diagnostic protocols generally defining the method used [2,13,18]. Although CT is not the technique of choice for urethral injuries, it is performed so frequently that urethral injuries are inevitably identified when performed for pelvic trauma. Chou et al [19] described the results of CT voiding urethrography using 16-multidetector CT in 13 men and found a high correlation between the results of conventional RUG and CT voiding urethrography for evaluating traumatic and nontraumatic urethral conditions. Findings of penetrating urethral trauma on CT voiding urethrography include extravasation of contrast media, irregularity of the urethral lumen, and hematomas.


Penetrating Trauma Lower Abdomen and Pelvis. CT Pelvis Pelvic CT without IV contrast provides limited evaluation for suspected penetrating injury to the lower urinary tract because of nonopacification of the urinary bladder lumen and lack of enhancement of the pelvic viscera [18]. However, it may be useful in detecting fluid or hematoma adjacent to the urinary bladder, prompting a follow-up evaluation with radiographic or CT cystography. Pelvic CT without IV contrast may be occasionally considered for evaluation of urethral or periurethral foreign body.


Penetrating Trauma Lower Abdomen and Pelvis. Pelvic CT with IV contrast allows improved assessment of the pelvic viscera and vessels compared with CT without IV contrast. However, evaluation for bladder injury remains limited because of suboptimal distension and nonopacification of the urinary bladder lumen. The use of antegrade cystography, during which the urinary bladder is gradually opacified by excretion of IV contrast, provides inadequate evaluation of bladder injury that is due to suboptimal distension of the bladder lumen, dilution of excreted contrast material by urine, and the time delay required for excretion of IV contrast [2].


Penetrating Trauma Lower Abdomen and Pelvis. Pelvic CT without and with IV contrast is suboptimal compared with CT cystography because of the reasons described in the previous 2 paragraphs. Specifically, pelvic CT without and with IV contrast does not provide


Penetrating Trauma Lower Abdomen and Pelvis. MRI Pelvis There is no relevant literature regarding the use of MRI in the evaluation of penetrating trauma to the lower urinary tract. MRI plays an ancillary role in the initial imaging evaluation of penetrating lower urinary tract injury that is due to the difficulty of monitoring a seriously injured patient in a strong magnetic field. MRI has been described for follow-up evaluation of urethral injury as an adjunctive tool for assessing complex urethral anatomic derangements [20,21].


Penetrating Trauma Lower Abdomen and Pelvis. Radiography Intravenous Urography There is no recent relevant literature regarding the use of an IV urogram in the evaluation of penetrating trauma to the lower urinary tract. An IV urogram is typically inadequate for evaluating the bladder and urethra after penetrating trauma because the contrast material within the bladder is diluted and the resting intravesical pressure is simply too low to demonstrate a small tear [15].


Penetrating Trauma Lower Abdomen and Pelvis. Fluoroscopy Retrograde Urethrography Patients with penetrating trauma to the penis should undergo RUG as the primary diagnostic procedure because of concern for injury of the anterior urethra [22]. Because posterior urethral injuries can also result from penetrating trauma to the pelvis and perineum, and are associated with pelvic fractures, a RUG should be performed before inserting a catheter [7,10,18]. In the past, a diagnosis of acute urethral injury often was based loosely on the clinical triad of 1) blood at the urethral meatus, 2) inability of the patient to void, and 3) a palpable urinary bladder. An inability to pass the catheter into the bladder was also considered diagnostic of a posterior urethral injury. It is now well established, however, that diagnostic catheterization is to be avoided, as it may convert a partial injury into a complete disruption [2,22]. In female patients with a suprapubic catheter in place, a descending or voiding urethrography may be sufficient; a RUG may also be performed with a small-caliber catheter pressed against, or slightly beyond, the urethral meatus [9].


Penetrating Trauma Lower Abdomen and Pelvis. Arteriography There is no relevant literature regarding the use of arteriography in the evaluation of penetrating trauma specific to the lower urinary tract. Arteriography can be useful in identifying an occult source of bleeding and can guide its subsequent therapeutic embolization [15]. Angioembolization has been described as a useful diagnostic and therapeutic tool in trauma patients with pelvic fractures and vascular injuries.


Penetrating Trauma Lower Abdomen and Pelvis. US Pelvis Transabdominal ultrasound (US) findings in bladder rupture and urethral evaluation with an endorectal probe have been described in the setting of blunt trauma [15], but US has not been routinely used for evaluating penetrating trauma of the lower urinary tract. Conversely, most or all seriously injured trauma patients will likely be evaluated with CT because of its speed and accuracy of evaluation.


Penetrating Trauma Lower Abdomen and Pelvis. US can be used to evaluate associated visceral lesions, such as solid or hollow organ rupture, and nonspecific peritoneal fluid [15]. The detection of peritoneal fluid in the presence of normal viscera or the failure to visualize the bladder after the transurethral introduction of saline are considered highly suggestive of bladder rupture [15]. As a practical matter, US is not definitive in bladder or urethral trauma and is almost never used for this diagnosis.


Penetrating Trauma Lower Abdomen and Pelvis. Adequate distention of the urinary bladder is crucial to detecting a perforation, especially in instances of penetrating trauma, as most instances of a false-negative retrograde cystogram were found in this situation [24,25]. To exclude bladder injury, a filling volume of at least 350 to 400 mL of contrast should be achieved. The catheter balloon should not be tightly maintained against the bladder neck because it could tamponade against a disruption and prevent detection of a leak in this region.


Penetrating Trauma Lower Abdomen and Pelvis. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.


Penetrating Trauma Lower Abdomen and Pelvis. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


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


Suspected Upper Extremity Deep Vein Thrombosis. Introduction/Background Soft-tissue swelling is usually due to an alteration in capillary hemodynamics causing motion of fluid from the vascular spaces into the interstitium, secondary to either increased plasma volume (eg, heart failure, pregnancy), increased capillary hydrostatic pressure (eg, superior vena cava syndrome, deep vein thrombosis [DVT], reflex sympathetic dystrophy, trauma), decreased capillary oncotic pressure (eg, cirrhosis, malnutrition), or increased capillary permeability (eg, allergic reactions, infection, inflammation). It can also be due to lymphatic obstruction (eg, lymphedema, malignancy). The etiology of acute isolated upper-extremity swelling is often apparent from the clinical history (eg, trauma, infection, inflammatory arthritis) or can be suspected when risk factors are present (eg, venous thrombosis due to a venous catheter).


Suspected Upper Extremity Deep Vein Thrombosis. Upper-extremity DVT (UEDVT) accounts for up to 10% of all diagnosed DVTs [1,2]. It can be primary in a third of cases due to venous thoracic outlet syndrome [3] (ie, effort-related thrombosis/Paget-Schroetter syndrome) and occasionally is idiopathic. Secondary UEDVT is far more common. Indwelling venous devices, such as catheters, pacemakers, and defibrillators, put patients at the highest risk of thrombus [1,4-10]. Other risk factors include advanced age, previous thrombophlebitis, postoperative state, hypercoagulability [4,11,12], heart failure [4], cancer [7,9-14], right-heart procedures, intensive care unit admissions [1,10], trauma, and extrinsic compression. Patients with certain abnormally elevated coagulation factors were demonstrated to be at increased risk of UEDVT [15]. Although many of the same risk factors for lower-extremity DVT also increase the risk for UEDVT, research is helping to elucidate certain variables unique to thrombi in the upper extremity [1,16].


Suspected Upper Extremity Deep Vein Thrombosis. Patients who develop UEDVT often present with symptoms of ipsilateral upper-extremity edema, pain, paresthesia and, in some instances, functional impairment [16]. Catheter-associated thrombosis may be asymptomatic, rather manifesting as catheter dysfunction or as an incidental finding upon imaging. Superficial thrombophlebitis is associated with local pain, induration, and, often, a palpable cord but is rarely associated with diffuse arm swelling [17]. Unilateral swelling indicates an obstructive process at the level of the brachiocephalic, subclavian, or axillary veins [17,18]. DVT limited to the brachial veins need not be associated with swelling. Isolated jugular vein thrombosis is asymptomatic and rarely causes swelling. There may be a correlation between UEDVT and lower- extremity DVT, and investigation of the lower extremities as well should be considered if an upper-extremity thrombus is found in the absence of a local cause [19].


Suspected Upper Extremity Deep Vein Thrombosis. Diagnosis of UEDVT Venous thrombosis must initially be considered in a patient with upper-extremity swelling because it typically requires anticoagulation and sometimes thrombolysis. Risk stratification can be performed from a combination of clinical features [20] or by using blood tests. Plasma levels of D-dimer, a degradation product of cross-linked fibrin that is elevated during thromboembolic events, is highly sensitive but not very specific [21] and may be useful in ruling out UEDVT in conjunction with low pretest probability [22-24]. However, D-dimer cannot assess the location and extent of DVT, which is critical for proper therapeutic management [25], and is unreliable to distinguish between acute DVT from recurrent DVT. Imaging is often required for definitive exclusion of DVT and to document


Suspected Upper Extremity Deep Vein Thrombosis. Reprint requests to: publications@acr.org


Suspected Upper Extremity Deep Vein Thrombosis. Suspected Upper-Extremity Deep Vein Thrombosis its location and extent. Noninvasive imaging is frequently the initial step to assess DVT and includes ultrasound (US), MRI, or CT. Catheter venography is slightly more invasive but remains the reference standard and offers the potential for initiation of therapy. Other techniques, such as photoplethysmography, lymphoscintigraphy, and fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT have been discussed in the literature as part of the workup for upper-extremity swelling, particularly when lymphedema is a potential cause [26-30].


Suspected Upper Extremity Deep Vein Thrombosis. Discussion of Procedures by Variant Variant 1: Suspected upper-extremity deep vein thrombosis. Initial imaging. US Duplex Doppler Upper Extremity US is a noninvasive test that can be performed at the bedside and used for serial evaluations. US grayscale imaging directly identifies thrombus by visualizing echogenic material in the vein and by lack of compression of the vein walls from manual external pressure by the US probe. Lack of compression is seen for both acute and chronic thrombus [12,31]. Acute hypoechoic thrombi may be missed using grayscale imaging alone.


Suspected Upper Extremity Deep Vein Thrombosis. US is most useful in the evaluation of veins peripheral to the subclavian, such as the jugular, axillary, basilic, cephalic, and brachial veins. US can also be used for the evaluation of arteriovenous fistulas in renal patients [40,41]. Compression cannot be used to evaluate more central veins because bony structures prevent visualization or compression of the vessel lumen, but flow in these central veins can be assessed by US [5,12,37]. If only blood flow abnormalities are seen, conventional venography may be necessary [12].


Suspected Upper Extremity Deep Vein Thrombosis. Correlative studies between US and venography show diagnostic sensitivities and specificities above 80% [5,8,12,31,34,35,38,39,42,43].


Suspected Upper Extremity Deep Vein Thrombosis. MRV Upper Extremity MRI uses several techniques to image the veins, with or without intravenous (IV) contrast agents. Noncontrast sequences include bright-blood and black-blood imaging [44] as well as flow-based imaging, such as time-of-flight [45-49] and phase-contrast imaging [47,50]. Contrast-enhanced MR venography (MRV) techniques are either high resolution or time resolved [47,51]. MRI can image the vessel lumen, the vessel wall, the surrounding structures, and assess for the presence of flow in the vessel. Thrombus can also be imaged directly [52]. Nephrogenic systemic sclerosis has been associated with exposure to some brands of gadolinium-based contrast agents in patients with renal failure [53].


Suspected Upper Extremity Deep Vein Thrombosis. Spin-echo techniques produce black-blood images [33,50] on which thrombus displays high intravascular signal often accompanied by venous enlargement. The high signal decreases after 6 months, and the technique is less useful for chronic thrombus [54]. This imaging technique is not always consistent and is affected by a variety of flow artifacts [50]. Newer double inversion-recovery techniques provide more reliable black-blood imaging [47]. Black-blood imaging is also useful to image the vessel wall, where scan parameters can be adjusted to enhance either T1 or T2 weighting.


Suspected Upper Extremity Deep Vein Thrombosis. Balanced gradient-echo techniques produce bright-blood images on which acute thrombus is relatively isointense to blood, making the sequence insensitive to detect acute thrombus [55,56]. The signal of thrombus varies in intensity over time. Cardiac-gated 3-D steady-state free precession and fast spin-echo techniques also produce bright-blood images. Because steady-state free precession images are T1/T2 weighted, visibility of clots depends on the age of thrombus. The weighted subtraction of fast spin-echo images in various phases of the cardiac cycle can help differentiate transient flow artifacts from true filling defects that persist over the cardiac cycle. Both techniques have been implemented for noncontrast MR angiography and appear promising [57-59].


Suspected Upper Extremity Deep Vein Thrombosis. Using time of flight to image veins is usually limited to a 2-D technique. Rapid flow through the imaging plane produces a bright signal, whereas slow flow or in-plane flow can produce a dark signal due to signal saturation [59]. On axial 2-D time-of-flight images, the jugular veins, right brachiocephalic vein, and superior vena cava are oriented in the superior-inferior direction and produce a bright signal, whereas the left brachiocephalic vein and subclavian


Suspected Upper Extremity Deep Vein Thrombosis. 3 Suspected Upper-Extremity Deep Vein Thrombosis


Suspected Upper Extremity Deep Vein Thrombosis. veins are oriented in-plane and produce a darker signal, often requiring sagittal 2-D time-of-flight images for best assessment. Breathing artifacts may also impair imaging quality [11,59,60]. Phase-contrast flow imaging has not been widely used for upper-extremity venography because of the slow flows that must be detected [59].


Suspected Upper Extremity Deep Vein Thrombosis. IV gadolinium-based contrast agents [59] can be administered during acquisition of 2-D or 3-D T1-weighted gradient-echo images with fat saturation to produce a very bright signal in patent vessels [45,61,62]. A 90- to 120- second delay is required after injection to allow the contrast bolus to enter the venous or equilibrium phase [47,59] and to generate an MRV. MRV has proven very useful to evaluate the central venous structures, which cannot be directly imaged by US, but US or venography are still preferred to image the more peripheral veins. A few IV contrast agents persist longer in the vessels and have been useful to image the venous structures. Fibrin-specific MR contrast agents can further enhance all thrombi and may even detect thrombi not readily visible in noncontrast imaging [63].


Suspected Upper Extremity Deep Vein Thrombosis. The dynamic filling of vessels by IV contrast agents can be imaged with time-resolved techniques. Such techniques can reduce both IV contrast volume and acquisition time while improving specificity when used as an adjunct to conventional MR sequences [64,65]. It has found use in protocols for whole-body venography [66] and was shown to produce images of comparable diagnostic quality but lower specificity compared with conventional MRV [67] in the assessment of central thoracic veins. It might eventually be used as a fast, noninvasive, and relatively safe imaging tool for screening and serial follow-up of patients with poor renal function, but further study is required [68].


Suspected Upper Extremity Deep Vein Thrombosis. Standard MRI sequences are always included in MRV protocols because they produce high-resolution images of the soft tissues surrounding the vessels and can help identify mimics of DVT and potential sources of extrinsic venous compression as well as signs of soft-tissue inflammation around the veins (edema on T2-weighted images and contrast enhancement on postcontrast T1-weighted sequences). MRV can be as effective as venography [46,62] but has limitations [33,45,50]. A meta-analysis found MRV to have both a high sensitivity and specificity [69], although the study did not focus on the upper extremities.


Suspected Upper Extremity Deep Vein Thrombosis. CTV Upper Extremity CT can be used to assess the lumen of venous structures. It involves the injection of an iodinated contrast agent [34,38]. Delayed imaging at 90 to 120 seconds can permit evaluation of the central veins. CT can detect thrombi in vascular lumen or stenosis of the lumen. It has been used to assess the jugular veins [70,71], the brachiocephalic veins [72,73], and the superior vena cava [72]. Perivascular inflammatory changes around acute thrombi can also be detected by CT [74]. CT can be used to visualize external processes causing vascular compression or invasion, such as neoplastic processes [75]. CT is the main imaging modality for staging neoplastic involvement in the mediastinum and axillae, which can include vascular invasion or compression. No large series of studies have looked at the diagnostic accuracy of this technique for diagnosing upper-extremity venous thrombosis, although extensive experience is accumulating with lower-extremity venous thrombosis. One small series showed that the performance of CT venography (CTV) is similar to that of conventional venography in the thoracic and upper- extremity veins and it evaluates the central extent of obstruction more effectively [75].


Suspected Upper Extremity Deep Vein Thrombosis. Nuclear Medicine Venography Upper Extremity Radionuclide venography involves the peripheral injection of radiopharmaceuticals or labeled small particles (eg, macroaggregated albumin, red blood cells, albumin, platelets) to assess drainage of extremities via the veins or lymphatics, or to directly detect the presence of thrombus (eg, platelets or specific markers). Patent vessels will take up the radiopharmaceuticals, whereas obstructed vessels will not. Failure to visualize specific veins, combined with


Suspected Upper Extremity Deep Vein Thrombosis. 4 Suspected Upper-Extremity Deep Vein Thrombosis


Suspected Upper Extremity Deep Vein Thrombosis. visualization of collateral veins, indicate either venous thrombosis or external compression of venous segments [2,25,26,28]. Radionuclide venography has been considered the reference standard for lymphedema [77]. For edema related to lymphatic obstruction, the presence of certain features, such as dermal backflow and lymph node asymmetry, can increase the diagnostic specificity after intradermal injection [78]. Some authors have indicated that differentiating between primary lymphedema and secondary lymphedema, such as that due to venous obstruction, may be limited when using intradermal lymphangiography alone [79]. MR lymphangiography is currently being evaluated as an alternative to conventional, radionuclide lymphoscintigraphy and may play a larger role in the future [80,81].


Suspected Upper Extremity Deep Vein Thrombosis. Radiography Chest Although chest radiography cannot assess vascular patency, it can identify factors that can cause external compression or invasion of vessels, such as cervical rib or a mass lesion. It can also identify intravascular material such as intact or fragments of wires and catheters.


Suspected Upper Extremity Deep Vein Thrombosis. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and rating round tabulations for each recommendation.


Suspected Upper Extremity Deep Vein Thrombosis. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


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


Suspected Upper Extremity Deep Vein Thrombosis. 5 Suspected Upper-Extremity Deep Vein Thrombosis


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Introduction/Background Placenta accreta spectrum disorder (PASD) is the current terminology recommended by the International Federation of Obstetrics and Gynecology (FIGO) and should replace terms such as abnormally adherent/invasive placenta or morbidly adherent placenta [1]. PASD refers to a variety of potential clinical complications, which may result from abnormal placental implantation. More specifically, placenta accreta refers to a defect in the decidua basalis in which the chorionic villi adhere directly to the myometrium with trophoblastic invasion. More invasive placentation includes placental increta, in which placental villi invade into the myometrium, and placenta percreta, in which the placenta villi invade through the myometrium and into the serosa and adjacent structures [2].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. A single placenta can demonstrate varying degrees of invasiveness, and a decidual defect may be accompanied by focal loss of myometrium, often related to prior surgery or trauma. The pathology and underlying mechanism for placenta accreta is not well understood but is thought to be related to a defect in trophoblastic function versus a failure of normal decidualization or a combination of both [1,3,4]. The risk of severe and even life-threatening hemorrhage is greatest at the time of delivery when a portion of the placenta does not separate in the usual fashion.


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Accurate antenatal diagnosis is needed to plan for an appropriate delivery strategy at an experienced center in order to reduce maternal morbidity [11].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Management of delivery is variable; however, the American Congress of Obstetricians and Gynecologists (ACOG) and FIGO recommend planned cesarean delivery with or without hysterectomy depending on the suspected severity of PASD around 34 to 38 weeks. There is currently insufficient evidence to determine the exact optimal time of delivery. The timing of the delivery is planned carefully on a case-by-case basis at around 34 to 38 weeks to achieve optimal fetal maturity and avoid the chance of spontaneous labor. Given that the majority of PASD are associated with placenta previa, they are at increased risk of prepartum hemorrhage as gestational age increases, which in turn is associated with increased risk of unscheduled delivery [11,12]. Although a planned delivery is preferred, a contingency plan for emergent delivery should be in place [4]. Obtaining radiologic and clinical data when PASD


Placenta Accreta Spectrum Disorder

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


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Reprint requests to: publications@acr.org


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Placenta Accreta Spectrum Disorder


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. is first suspected can play a significant role in formulating an appropriate delivery strategy and contingency plan. Ideally after initial diagnosis, high-risk patients should be followed closely by experienced centers where emergent mobilization of a multidisciplinary team needed for a scheduled or unscheduled delivery is feasible [13].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Discussion of Procedures by Variant Variant 1: Low risk for placenta accreta spectrum disorder. No known clinical risk factors. Initial imaging. Women who do not have any clinical risk factors and no evidence of previa during an 18- to 22-week anatomy scan can be followed per ACOG clinical guidelines [4].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. MRI Abdomen and Pelvis (Without and With IV Contrast) There is no relevant literature to support the use of MRI without or with intravenous (IV) contrast in the initial imaging evaluation for low-risk pregnancy unless concerning findings are present on routine ultrasound (US) [13].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. MRI Abdomen and Pelvis (Without IV Contrast) There is no relevant literature to support the use of MRI without IV contrast in the initial imaging evaluation for low-risk pregnancy unless concerning findings are present on routine US [13].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. US Duplex Doppler Pregnant Uterus Doppler evaluation should be considered if any abnormalities of placental tissue or in the placental myometrial interface are detected on grayscale imaging regardless of placental location [4,14].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. US Pregnant Uterus Transabdominal Routine transabdominal US evaluation of placental location, appearance, and its relationship to internal os is done as documented in the ACR-ACOG-AIUM-SMFM-SRU Practice Parameter for the Performance of Standard Diagnostic Obstetrical Ultrasound [15].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. US Pregnant Uterus Transvaginal Transvaginal (or transperineal) US views may be helpful in visualizing the internal cervical os and its relationship to the placenta if not clear on transabdominal US [15].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Variant 2: High risk for placenta accreta spectrum disorder. Initial Imaging. The main risk factors for PASD include prior uterine surgery, including myomectomy, dilatation, and curettage, most notably cesarean delivery with concomitant anterior placenta previa, followed by advanced maternal age and in vitro fertilization. As many as 40% of women with placenta previa and three prior cesarean deliveries will develop PASD [8-10]. Women with high risk based on clinical history and/or US findings should be considered for referral for specialist imaging to confirm or exclude this diagnosis.


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Numerous studies have evaluated the use of US for the diagnosis of placenta accreta. US sensitivities have been reported to range from 77% to 97% with specificities of 96% to 98%, positive predictive value of 65% to 93%, and negative predictive value of 98% for PASD [16-21]. A meta-analysis of over 3,500 patients showed US to have high accuracy for diagnosing abnormal placentation, which improved with the addition of color Doppler [3]. These results are mainly applicable for the anterior placenta (either low lying or previa) in patients with previous cesarean delivery [3].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. As per the recently updated SMFM-ACOG-SGO consensus document, US evaluation is important, but the absence of US findings does not preclude a diagnosis of PASD [13].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. In patients with known history of prior cesarean delivery and/or low placenta or placenta previa, special attention should be paid on first trimester or nuchal translucency scanning to determine if there is a low implantation or cesarean section scar pregnancy that has been associated with increased risk for PASD [6,10,22-25].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. MRI Abdomen and Pelvis (Without and With IV Contrast) There is insufficient evidence to support the use of gadolinium based contrast agents in MRI for this indication because there is no literature clearly establishing improved delineation of placenta and myometrium and the use of gadolinium based contrast agents remains controversial in pregnancy [26,27]. One series using gadolinium contrast compared imaging findings to pathology and reported good accuracy of US, with sensitivity for placenta accreta of 77%, specificity of 96%, but improved accuracy with MRI with corresponding sensitivity of 88% and specificity of 100% [20]. Gadolinium-based contrast agents are considered category C drugs, and their use should be considered only if the benefits outweigh the risks to the fetus. For example, IV contrast may be considered as an exception immediately prior to delivery or, in rare cases, in circumstances in which termination is planned [14].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Placenta Accreta Spectrum Disorder MRI Abdomen and Pelvis (Without IV Contrast) MRI without IV contrast may play a complementary or selective role in situations in which US is equivocally nondiagnostic, severely abnormal in the setting of posterior placentation, or limited by obesity that limits US assessment [14,20,28-34]. MRI may be used to assist with surgical planning, such as choosing between hysterectomy and a more conservative surgery. The knowledge of the precise topography, including depth or laterality of invasion based on the MRI findings, can alter the surgical approach with regard to a need for ureteral stenting, vascular clamping, and/or embolization [3,35]. It has been suggested that MRI is particularly valuable in detecting placental invasion to parametrium [11].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Because MRI is also associated with both false-positive and false-negative diagnoses [36], the examination may be complementary to the US evaluation. The earliest recommended timing for a diagnostic quality MRI scan after a suspicious US is after 24 weeks [32]. An earlier MRI may be useful in a limited setting, such as preoperative planning for termination of the pregnancy or in the setting of severe disease for staging. Interobserver agreement has been shown to improve with extent of placental invasion [28]. At least four studies have performed direct comparison of MRI with US and found sensitivity of 93% and specificity of 94% for MRI compared with 88% and 96%, respectively, for US [37-40]. Warshak et al [20] advised a 2-stage protocol, starting with US and followed by MRI. Pregnant patients can be informed that there are no known deleterious effects on the fetus performed in 1.5T or 3.0T magnets [41].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. US Duplex Doppler Pregnant Uterus The addition of Doppler imaging can improve both detection and progression of the presence of increased placental vascular flow, subplacental vascularity, and vascularity at the bladder uterine-serosal interface, with vessels seen crossing or bridging from placenta to bladder. The presence of multiple vascular lacunae in the placenta is thought to be related to the exposure to pulsatile blood flow, high-velocity blood flow from myometrium to lacunae. The presence of placental lacunae in the second trimester scan has been shown to have the highest sensitivity and positive predictive value for placenta accreta [37]. Comstock et al [37] observed lacunae in a majority of placenta accreta patients in second trimester scans. When lacunae are multiple, large, and irregular, they are highly suggestive of placenta accreta, but placenta accreta can occur in their absence.


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. On grayscale transabdominal US, the imaging findings that suggest placenta accreta include the presence of intraplacental lacunae (sonolucent spaces that can have slow-moving to more suspicious turbulent moving flow,


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Placenta Accreta Spectrum Disorder also called intraplacental lakes), loss of the normal hypoechoic retroplacental zone or clear space, reduced myometrial thickness of <1 cm, placental bulging (ballooning of the uterus containing placenta from its expected plane into surrounding tissue, usually into the urinary bladder), and the presence of bladder wall abnormalities. Interruption, thickening, or irregularity of the uterine serosa-bladder line interface has been reported to have high sensitivity and specificity for accreta, more striking as the depth of invasion progresses [2]. Sensitivity of US has been reported to range from 77% to 93%, with positive predictive value of 65% to 93%, and prevalence of 9% to 44% [6,16,37,38,46]. As an isolated finding, loss of the normal retroplacental zone has a reported sensitivity of only 52% and specificity of 57%, with a high false-positive rate of 21% because the normal retroplacental zone may also be absent in normal anterior placentas as well [2,46-48]. Another limitation in the assessment for placental invasion is when the placenta is not low lying. Recognition of a history of prior surgery in these cases may be helpful, as well as meticulous attention to placental morphology and structure.


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. US Pregnant Uterus Transvaginal Transvaginal US scanning should be used in conjunction with transabdominal US scanning, particularly to evaluate the anterior lower uterine segment myometrium, placenta, and myometrial-placental interface because it can provide more detailed higher-resolution evaluation [15].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Variant 3: Follow-up of placenta accreta spectrum disorder. Women at high risk for PASD or with a known diagnosis of PASD should undergo a follow-up US to re-evaluate the evolving relationship between placental and umbilical vessel location, internal cervical os, placental edge thickness, internal architecture and morphology, and cervical length. These findings may highlight which patients are at highest risk for developing symptoms and complications and may need closer monitoring for potential earlier delivery.


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. MRI Abdomen and Pelvis (Without and With IV Contrast) Regarding the use of MRI with IV contrast, there is no evidence to support gadolinium benefits and its ability to improve the delineation of placenta and myometrium because its use in pregnancy remains controversial, and currently there is no clear evidence to support its use for PASD [26,27]. One series using gadolinium contrast compared imaging findings to pathology and reported good accuracy of US, with sensitivity for placenta accreta of 77%, specificity of 96%, but improved accuracy with MRI with corresponding sensitivity of 88% and specificity of 100% [17]. Gadolinium-based contrast agents are considered category C drugs, and use should be considered only if benefits outweigh the risks to the fetus. For example, contrast may be considered as an exception immediately prior to delivery or rare cases and circumstances in which termination is planned [14].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. In summary, use of MRI in the diagnosis of this disorder is to be more supportive in the setting of a limited, difficult, or equivocal US study. It also may play a role in defining the distribution of placental invasion and defining uterine vascular territory involved and may help with the decision for intervention. When US and MRI are used together but differ in terms of their findings, the more invasive level of PASD should be used to guide management.


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. US Duplex Doppler Pregnant Uterus Duplex Doppler imaging should be performed whenever possible. The addition of Doppler imaging can improve detection and evaluation of progression if previously noted of the presence of increased placental vascular flow, subplacental vascularity, and vascularity at the bladder uterine-serosal interface, with vessels seen crossing or


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. US Pregnant Uterus Transvaginal Transvaginal US should accompany transabdominal US whenever possible. If placenta is located near lower uterine segment, a high-resolution transvaginal US scan provides a more detailed evaluation of placental myometrial and bladder interface and areas of potential invasion. If placenta is distant from lower uterine segment, transvaginal US is unlikely to be of any additional benefit [15].


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and rating round tabulations for each recommendation.


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder

Placenta Accreta Spectrum Disorder. Placenta Accreta Spectrum Disorder


Seizures and Epilepsy

Seizures and Epilepsy. Introduction/Background A seizure is defined as a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain [1]. The International League Against Epilepsy (ILAE) defines epilepsy as having 1) at least two unprovoked seizures occurring more than 24 hours apart, 2) one unprovoked seizure and a probability of further seizures similar to the general recurrence risk after two unprovoked seizures, occurring over the next 10 years, or 3) diagnosis of an epilepsy syndrome.


Seizures and Epilepsy

Seizures and Epilepsy. Special Imaging Considerations In addition to the known benefits of using fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET for the localization of epileptogenic foci, there are known alterations of neurotransmitters and receptors in epilepsy [8]. Gamma aminobutyric acid is an inhibitory neurotransmitter known to be important in the regulation of epileptic activity and is evaluated using 11C-flumazenil [9]. Opioids can reduce the spread of electrical activity, can have an anticonvulsant effect [10], and can be evaluated with several tracers including 11C-carfentanil. Serotonin can also


Seizures and Epilepsy

Seizures and Epilepsy. aEinstein Healthcare Network, Philadelphia, Pennsylvania. bPanel Chair, Montefiore Medical Center, Bronx, New York. cOhio State University, Columbus, Ohio. dDuke University School of Medicine, Durham, North Carolina; American College of Emergency Physicians. eOttawa Hospital Research Institute and the Department of Radiology, The University of Ottawa, Ottawa, Ontario, Canada; Canadian Association of Radiologists. fUniversity of Michigan, Ann Arbor, Michigan. gMayo Clinic, Rochester, Minnesota. hUniversity of Kansas Medical Center, Kansas City, Kansas. iUniversity of California Los Angeles, Los Angeles, California; American Academy of Neurology. jUniversity of California San Diego Medical Center, San Diego, California. kOregon Health & Science University, Portland, Oregon. lNorthwestern University Feinberg School of Medicine, Chicago, Illinois; Neurosurgery expert. mAlbert Einstein College of Medicine Montefiore Medical Center, Bronx, New York, Primary care physician. nWalter Reed National Military Medical Center, Bethesda, Maryland. oUniversity of Illinois at Chicago College of Medicine, Chicago, Illinois, Neurosurgery expert. pColumbia University Medical Center, New York, New York. qSpecialty Chair, Atlanta VA Health Care System and Emory University, Atlanta, Georgia.


Seizures and Epilepsy

Seizures and Epilepsy. Reprint requests to: publications@acr.org


Seizures and Epilepsy

Seizures and Epilepsy

Seizures and Epilepsy. Seizures and Epilepsy


Seizures and Epilepsy

Seizures and Epilepsy. have an anticonvulsant effect and can be evaluated with different tracers including 18F-MPPF [11]. Changes in dopamine receptors have also been associated with various forms of epilepsy [12] and can be evaluated with 18F- fallypride.


Seizures and Epilepsy

Seizures and Epilepsy. Alpha-[11C]methyl-L-tryptophan is a tryptophan analogue and has been shown to be a useful radiotracer in assessing seizures in patients with tuberous sclerosis, temporal lobe epilepsy (TLE), and cortical dysplasia [13].


Seizures and Epilepsy

Seizures and Epilepsy. Diffusion tensor imaging that utilizes data from directionally encoded diffusion-weighted imaging has also been utilized to assess disruption in white matter tracks following trauma; however, its use in this capacity remains investigational [14].


Seizures and Epilepsy

Seizures and Epilepsy. Discussion of Procedures by Variant Variant 1: New-onset seizure. Unrelated to trauma. Initial imaging. CT Head Noncontrast CT has a central role in the emergent situation of acute seizures as it can accurately and rapidly identify structural pathology, such as intracranial hemorrhage, stroke, vascular malformation, hydrocephalus, and tumors, which may require either supportive treatment or neurosurgical care [15,16]. CT is also sensitive in detection of calcified and bony lesions. It is less sensitive in detection of lesions in the orbitofrontal and medial temporal regions, and also in the detection of small cortical lesions [17]. Contrast-enhanced CT can be considered to better define tumors and evaluate for infection; however, MRI is a better option in this situation. Overall success in detecting lesions in focal epilepsies with CT is much lower than with MRI at only 30% [17]. Importantly, the ILAE recommendation for neuroimaging in the acute situation is for CT if there is a need to have ready access to the patient during scanning. [15].


Seizures and Epilepsy

Seizures and Epilepsy. FDG-PET/CT Brain There is no relevant literature regarding the use of FDG-PET/CT as an initial imaging study in the evaluation of new-onset seizure unrelated to trauma.


Seizures and Epilepsy

Seizures and Epilepsy. MEG There is no relevant literature regarding the use of magnetoencephalography (MEG) as an initial imaging study in the evaluation of new-onset seizure unrelated to trauma.


Seizures and Epilepsy

Seizures and Epilepsy. MRI Functional (fMRI) Head There is no relevant literature regarding the use of functional MRI (fMRI) as an initial imaging study in the evaluation of new-onset seizure unrelated to trauma.


Seizures and Epilepsy

Seizures and Epilepsy. MRI Head MRI serves multiple purposes for new-onset seizures, including identifying and characterizing focal causative lesions as well as assessing progression. MRI is an important tool for determining prognosis as well as a treatment strategy. In the nonemergent situation, MRI is the imaging study of choice when indicated [15-18]. In an emergent setting, CT may be quicker as it does not require additional safety screening and has decreased requirements for extended patient monitoring [16]. In general, all patients with epilepsy should undergo an MRI. Some forms of epilepsy, however, have a low yield of structural lesions on MRI, such as those with typical forms of primary generalized epilepsy, benign focal epilepsies of childhood with characteristic clinical and electroencephalography (EEG) features, and early onset childhood epilepsy with occipital spikes and adequate response to antiepileptic drugs, so in these cases, some authors do not advocate utilizing MRI [17].


Seizures and Epilepsy

Seizures and Epilepsy


Seizures and Epilepsy

Seizures and Epilepsy. use of intravenous (IV) contrast is not routinely necessary; however, it is useful when images without IV contrast are not sufficient or if neoplasm or inflammatory condition is suspected [17].


Seizures and Epilepsy

Seizures and Epilepsy. HMPAO SPECT or SPECT/CT Brain Ictal and Interictal There is no relevant literature regarding the use of single-photon emission computed tomography (SPECT) or SPECT/CT as an initial imaging study in the evaluation of new-onset seizure unrelated to trauma.


Seizures and Epilepsy

Seizures and Epilepsy. Variant 2: New-onset seizure. History of trauma. Initial imaging. CT Head Noncontrast CT has a central role in the emergent situation of immediate post-traumatic seizures as it can accurately and rapidly identify pathology related to trauma, such as acute intracranial hemorrhages, and other pathology that may be the cause of the apparent traumatic condition, including stroke, cerebral edema, vascular malformation, hydrocephalus, skull fractures, foreign bodies, and tumors [14-16,19]. CT can quickly identify mass effect, such as tonsillar herniation or midline shift, that requires urgent intervention. CT can be performed quickly and without the need for screening for ferromagnetic materials. However, note that the overall success of CT in detecting focal lesions in epilepsy is low at approximately 30% [17]. There is no role for contrast-enhanced CT in the setting of trauma.


Seizures and Epilepsy

Seizures and Epilepsy. FDG-PET/CT Brain There is no relevant literature regarding the use of FDG-PET/CT as an initial imaging study in the evaluation of new-onset seizure with history of trauma. Recent literature has described increases in amyloid levels in TBI using PET amyloid; however, the use of this modality remains investigational [20].


Seizures and Epilepsy

Seizures and Epilepsy. MEG There is no relevant literature regarding the use of MEG as an initial imaging study in the evaluation of new-onset seizure with history of trauma.


Seizures and Epilepsy

Seizures and Epilepsy. MRI Functional (fMRI) Head There is no relevant literature regarding the use of fMRI as an initial imaging study in the evaluation of new-onset seizure with history of trauma. There is evidence that TBI can be associated with both increases and decreases in cerebral blood flow during the acute stages of injury; however, the use of this modality remains investigational [20].


Seizures and Epilepsy

Seizures and Epilepsy. MRI Head MRI is effective in assessing for traumatic pathology; however, because of the longer duration of the examination compared with CT and the additional evaluation necessary for safety clearance, MRI has a secondary role in the acute traumatic setting [15,16,18]. Nevertheless, MRI is recommended in patients with acute TBI if noncontrast CT is normal and there are persistent unexplained neurologic findings [19]. Compared with CT, MRI is more sensitive in assessment of smaller hemorrhages related to contusions and microhemorrhages related to diffuse axonal injury due to the use of GRE, with susceptibility-weighted imaging, which is even more sensitive. In addition, diffusion- weighted images are sensitive in detection of nonhemorrhagic diffuse axonal injury lesions [21]. The identification of microhemorrhages is important as it may predict injury severity and outcome; however, this is controversial [19,22]. In the setting of seizures with history of trauma, MRI can be considered if there are focal neurologic findings [17] as MRI is effective in the assessment of chronic blood deposition, gliosis, and encephalomacia. There is no indication for IV contrast in the setting of TBI; however, subacute contusions can enhance because of disruption of the blood-brain barrier [19].


Seizures and Epilepsy

Seizures and Epilepsy. HMPAO SPECT or SPECT/CT Brain Ictal and Interictal There is no relevant literature regarding the use of SPECT or SPECT/CT as an initial imaging study in the evaluation of new-onset seizure with history of trauma.


Seizures and Epilepsy

Seizures and Epilepsy. Variant 3: Known seizure disorder. Unchanged seizure semiology. CT Head CT is less sensitive to focal pathologies when compared with MRI and is less specific in its characterization of findings, limiting its utility in the setting of known seizures that are unchanged [16,23]. However, CT can be helpful for characterizing structural findings in seizure etiologies that contain dystrophic calcifications, such as with oligodendrogliomas and tuberous sclerosis. [23].


Seizures and Epilepsy

Seizures and Epilepsy

Seizures and Epilepsy. Seizures and Epilepsy


Seizures and Epilepsy

Seizures and Epilepsy. FDG-PET/CT Brain FDG-PET is well established as a modality to localize an epileptogenic focus and can provide additional information regarding the functional status of the uninvolved brain. Reported sensitivities of PET in the assessment of TLE ranges from 87% to 90% and extra-TLE ranges from 38% to 55% [24-27]. FDG when combined with perfusion ictal-interictal SPECT and subtraction ictal SPECT co-registered to MRI demonstrated improved detection of the epileptogenic zone [28]. A major limitation of interictal FDG-PET is that it cannot precisely identify the surgical margin because the area of hypometabolism often extends beyond the epileptogenic zone [8]. FDG-PET allows for higher-resolution and better-quality images compared with SPECT [29]. In cases of unchanged seizure semiology yet are refractive to medical therapy, FDG-PET can identify lesions missed on CT or MRI [30].


Seizures and Epilepsy

Seizures and Epilepsy. MEG There is no relevant literature regarding the use of MEG in the evaluation of known seizure disorder with unchanged seizure semiology.


Seizures and Epilepsy

Seizures and Epilepsy. MRI Functional (fMRI) Head There is no relevant literature regarding the use of fMRI in the evaluation of known seizure disorder with unchanged seizure semiology.


Seizures and Epilepsy

Seizures and Epilepsy. MRI Head The excellent gray-white matter differentiation and multiplanar imaging capability of MRI are characteristics that contribute to greater sensitivity and accuracy of MRI compared with CT [8,17,31]. Low-grade gliomas have been identified on MRI in patients with a history of epilepsy for >20 years [17], and so there is use in assessment of seizures that are chronic and longstanding to assess for changes in structural abnormalities. Some authors suggest that priority for imaging with MRI should be given to patients who have focal findings on a neurologic examination [17]. Patients being evaluated for seizures with normal MRI scans on a 1.5T scanner may have findings identified on repeat MRI imaging on 3.0T scanners, even with unchanged seizure semiology [32,33].


Seizures and Epilepsy

Seizures and Epilepsy. HMPAO SPECT or SPECT/CT Brain Ictal and Interictal There is no relevant literature regarding the use of SPECT or SPECT/CT in the evaluation of known seizure disorder with unchanged seizure semiology.


Seizures and Epilepsy

Seizures and Epilepsy. Variant 4: Known seizure disorder. Change in seizure semiology or new neurologic deficit or no return to previous neurologic baseline. CT Head CT can rapidly assess for intracranial hemorrhage, stroke, vascular malformation, hydrocephalus, or progression of tumors in the setting of changes in seizure semiology or new neurologic deficit. However, CT has decreased sensitivity and specificity to pathology in the brain with overall less gray-white matter differentiation compared with MRI [16,17,23].


Seizures and Epilepsy

Seizures and Epilepsy. FDG-PET/CT Brain Changes in seizure semiology may be secondary to interval changes in an epileptogenic focus, and as such, FDG- PET may identify these changes and can provide additional information regarding the functional status of the uninvolved brain, including assessment of the functional deficit zone. Reported sensitivities of PET in the assessment of TLE ranges from 87% to 90% and extra-TLE ranges from 38% to 55% [24-27]. FDG when combined with perfusion ictal-interictal SPECT and subtraction ictal SPECT co-registered to MRI demonstrated improved detection of the epileptogenic zone [28]. A major limitation of interictal FDG-PET is that it cannot precisely identify the surgical margin because the area of hypometabolism often extends beyond the epileptogenic zone [8]. FDG- PET allows for higher-resolution and better-quality images compared with SPECT [29]. FDG-PET is an effective problem-solving tool in the workup of seizures in the setting of a negative MRI scan [30].


Seizures and Epilepsy

Seizures and Epilepsy. MEG There is no relevant literature regarding the use of MEG in the evaluation of known seizure disorder with changes in seizure semiology unless it is in the setting of presurgical planning.


Seizures and Epilepsy

Seizures and Epilepsy. MRI Functional (fMRI) Head There is no relevant literature regarding the use of fMRI in the evaluation of known seizure disorder with changes in seizure semiology unless it is in the setting of presurgical planning.


Seizures and Epilepsy

Seizures and Epilepsy


Seizures and Epilepsy

Seizures and Epilepsy. MRI Head In the setting of interval changes of seizure semiology, MRI is the study of choice to evaluate for new structural lesions [17,34]. MRI is the modality of choice in assessment of the progression of known lesions, and as such is an important tool for prognostic considerations [17], and the use of specific protocols IV contrast considered depending on the underlying etiology. Some authors advocate neuroimaging only if there are focal findings on a neurologic examination [17]. One study, which evaluated repeat MRI in seizure patients, including those with change in seizure semiology, demonstrated a 21% increase of findings, which were not identified in initial MRI scans [32].


Seizures and Epilepsy

Seizures and Epilepsy. HMPAO SPECT or SPECT/CT Brain Ictal and Interictal There is no relevant literature regarding the use of SPECT or SPECT/CT in the evaluation of known seizure disorder with changes in seizure semiology unless it is in the setting of presurgical planning.


Seizures and Epilepsy

Seizures and Epilepsy. Variant 5: Known seizure disorder. History of tumor. CT Head CT can assess for interval changes in tumor and associated edema, mass effect, hydrocephalus, and tumor- associated hemorrhage. These features can be assessed without IV contrast, often using secondary signs of underlying mass; however, adding IV contrast adds sensitivity and specificity to directly visualize smaller lesions. Overall, CT has decreased sensitivity and specificity to pathology in the brain with overall less gray-white matter differentiation compared with MRI [16,17,23]. CT is effective in the assessment of tumors that contain dystrophic calcifications, such as oligodendrogliomas and tuberous sclerosis [23]. CT has limited value in assessment of tumor recurrence versus radiation necrosis given the overlap of imaging characteristics whether IV contrast is used or not [35].


Seizures and Epilepsy

Seizures and Epilepsy. FDG-PET/CT Brain FDG-PET is well established in the literature for the assessment of residual or recurrent tumors following therapy [36]. FDG-PET can also be used to follow low-grade tumors for evidence of degeneration or transformation into a higher-grade malignancy [36]. FDG-PET can differentiate radiation necrosis versus tumor recurrence with sensitivity of 65% to 81% and specificity of 40% to 94% [36]. More recently, FDG-PET co-registered with MRI may have a higher sensitivity in distinguishing radiation necrosis from tumor recurrence at 86% [37].


Seizures and Epilepsy

Seizures and Epilepsy. MEG There is no relevant literature regarding the use of MEG in the evaluation of known seizure disorder with history of tumor unless it is in the setting of presurgical planning.


Seizures and Epilepsy

Seizures and Epilepsy. MRI Functional (fMRI) Head There is no relevant literature regarding the use of fMRI in the evaluation of known seizure disorder with history of tumor unless in the setting of presurgical planning.


Seizures and Epilepsy

Seizures and Epilepsy. MRI Head MRI of the brain with and without IV contrast is a first-line imaging study in the assessment of residual or recurrent tumors following therapy and is routinely used to monitor malignancy [35,38]. In the setting of stability or resolution, MRI can be used for surveillance; however, in the case of new MRI findings, there can be overlap of imaging characteristics of malignancy versus radiation necrosis [35,36]. Nevertheless, certain characteristics are associated more with recurrent tumor, such as lower apparent diffusion coefficient values compared with radiation necrosis [35]. In addition, the phenomenon of pseudoprogression, a transient period of apparent radiographic deterioration when early delayed radiation effects (<3 months following radiation) can be seen, which can also complicate interpretation of the MRI. Pseudoresponse can also be problematic, with an apparent decrease in contrast enhancement in a tumor due to changes in vascular permeability as opposed to true tumor response also resulting in a complicated interpretation [39]. MR spectroscopy and MR perfusion can be effective adjunct imaging examinations to complement conventional MRI [38].


Seizures and Epilepsy

Seizures and Epilepsy. HMPAO SPECT or SPECT/CT Brain Ictal and Interictal There is no relevant literature regarding the use of SPECT or SPECT/CT in the evaluation of known seizure disorder with history of tumor unless in the setting of presurgical planning.


Seizures and Epilepsy

Seizures and Epilepsy. Variant 6: Known seizure disorder. Surgical candidate or surgical planning. CT Head Evaluation of seizures was greatly advanced by the clinical introduction of CT in the early 1970s [40,41] because of its cross-sectional capabilities that were not possible with radiographs. However, CT is outperformed by MRI in


Seizures and Epilepsy

Seizures and Epilepsy

Seizures and Epilepsy. Seizures and Epilepsy