Contrast-Enhanced Ultrasound of the Indeterminate Renal Mass, From the AJR "How We Do It" Special Series.

Contrast-enhanced ultrasound (CEUS) is distinguished from CT and MRI by the use of microbubble ultrasound contrast agents (UCAs) with intravascular blood pool distribution. When performing CEUS, low-intensity ultrasound allows real-time tissue subtraction imaging, whereas high-intensity ultrasound leads to microbubble destruction, enabling visualization of the contrast inflow pattern. CEUS has exceptional contrast resolution that enables the detection of even minimal blood flow, achieving very high NPV for ruling out vascular perfusion and providing high frame rates in the evaluation of tissue perfusion dynamics. UCAs undergo hepatic metabolism and pulmonary clearance, ensuring safety in patients with renal impairment. CEUS excels in distinguishing solid from cystic renal masses, with higher sensitivity than CT or MRI for detection of lesion enhancement. CEUS can aid the further characterization of both solid and cystic lesions and may have particular applications in the surveillance of cystic masses and surveillance after renal cell carcinoma ablation. This review describes the use of CEUS to help characterize indeterminate renal masses, based on the authors' institutional experience. The article highlights key differences between CEUS and CT or MRI, and provides practical insights for performing and interpreting CEUS of renal masses.

Contrast-enhanced US of the Liver and Kidney: A Problem-solving Modality.

Contrast-enhanced US (CEUS) has an important role as a supplement to CT or MRI in clinical practice. The main established utilizations are in the liver and the kidney. The primary advantages of CEUS compared with contrast-enhanced CT or MRI relate to its superior contrast resolution, real-time continuous scanning, pure intravascular nature, portability, and safety-especially in patients with renal impairment or CT or MRI contrast agent allergy. This article focuses on the use of CEUS in the liver and kidney.

The added value of contrast-enhanced ultrasound in evaluation of indeterminate small solid renal masses and risk stratification of cystic renal lesions.

OBJECTIVES: To investigate accuracy of contrast-enhanced ultrasound (CEUS) to characterize indeterminate small solid renal masses (sSRMs), excluding lipid-rich AMLs, and cystic renal masses (CRMs) according to the proposed Bosniak Classification 2019 MATERIALS AND METHODS: CEUS of pathology-proven CRMs and sSRMs (without definite enhancement or macroscopic fat on CT/MRI), and CRMs with ≥18 months follow-up were retrospectively reviewed. Two radiologists blindly categorized CRMs according to new Bosniak Classification on CT/MRI. On CEUS, two other radiologists evaluated arterial-phase enhancement of sSRMs relative to renal cortex and categorized CRMs following new Bosniak Classification. Fisher's exact/chi-squared test was used to compare categorical variables, and Cohen κ statistics for inter-observer agreement RESULTS: A total of 237 patients had 241 lesions: 161 pathology-proven sSRMs (122 malignant and 39 benign), 29 pathology-proven CRMs, 51 CRMs with adequate follow-up. Arterial-phase enhancement < renal cortex predicted malignancy with specificity of 97.4% (38/39) (CI 85.6-99.9%), and positive predictive value (PPV) of 98.2% (54/55) (CI 90.4-99.9%). Inter-observer kappa was 0.95. In pathology-proven CRMS, sensitivity of CEUS vs CT/MRI was 100% (15/15) (CI 79.6-100%) vs 60% (9/15) (CI 35.8-80.1%) (p value = .002) and negative predictive value (NPV) 100% (2/2) (CI 17.8-100%) vs 25% (2/8 ) (CI 4.4-59.1%) (p value < 0.0001), with similar specificity (50%) and PPV- 88.2% (15/17) (CI 65.7-97.9%) vs 81.8% (9/11) (CI 52.3-96.8%) ( p value = 0.586). Bosniak Classification inter-observer kappa was 0.92 for CEUS vs 0.68 for CT/MRI (p value = 0.009). CONCLUSION: In our cohort, CEUS had high specificity and PPV to diagnose RCC in sSRMs excluding lipid-rich AML. CEUS had significantly higher sensitivity/NPV to diagnose malignancy in CRMs as compared to CT/MRI. KEY POINTS: • Once lipid-rich AML is excluded by the other modalities, sSRM arterial phase hypo-enhancement relative to renal cortex on CEUS yielded high specificity (97.4%) and PPV (98.2%) to diagnose RCC. • When applying the proposed Bosniak Classification 2019, CEUS showed higher sensitivity compared to CT/MRI (100% vs 60%), p value=.0024, in the stratification of cystic renal masses to diagnose malignancy. • CEUS may reduce the number of CT/MRI Bosniak IIF lesions by assigning them to either II or III/IV categories.

Quality of ultrasonography reporting and factors associated with selection of imaging modality for uterine fibroids in Canada: results from a prospective cohort registry.

BACKGROUND: Uterine fibroids are common in women and their management is heavily influenced by information gathered through imaging. We aimed to evaluate the type and quality of imaging performed for assessment of uterine fibroids in Canada. METHODS: Starting in July 2015, premenopausal women with symptomatic fibroids were enrolled in a prospective, noninterventional, observational registry (Canadian Women With Uterine Fibroids Registry [CAPTURE]) that included 19 Canadian sites. Clinical characteristics were extracted from the baseline visit. We evaluated the association between demographic and clinical variables of interest with regard to imaging type using unadjusted and adjusted logistic regression models. RESULTS: Of 1493 women, 1148 had ultrasonography, 135 had magnetic resonance imaging (MRI), 80 had other types of imaging and 130 did not have imaging reported within 12 months of the baseline visit. After adjusting for demographic and clinical characteristics, patients who underwent MRI had larger fibroids (odds ratio [OR] per 1-cm increase 1.11, 95% confidence interval [CI] 1.05-1.17) and more numerous fibroids (1 v. > 1; OR 1.74, 95% CI 1.14-2.64) compared with those who underwent ultrasonography only. For ultrasonography reporting, quality criteria were met for 268 of 1148 patients (23.3%). There was a difference in the quality of reporting among the 19 sites (p < 0.001). Logistic regression model accounting for within-site variability showed that reporting results from ultrasonography in the province of Quebec were less likely to meet all quality criteria (OR 0.20, 95% CI 0.06-0.66) and those from sites in more populated cities (≥ 400 000 inhabitants) were more likely to do so (OR 6.15, 95% CI 2.20-17.18). INTERPRETATION: We determined that imaging modality for fibroids is associated with patient characteristics. The quality of reporting results for ultrasonography of fibroids in Canada falls short of internationally endorsed guidelines and needs improvement. STUDY REGISTRATION: ClinicalTrials.gov, no. NCT02580578.

Negative Predictive Value of Contrast-Enhanced Ultrasound of Liver and Kidney Thermal Ablation Sites for Local Tumour Progression During Long-term Follow-up: A Retrospective Consecutive Study.

PURPOSE: To determine negative predictive value (NPV) of contrast-enhanced ultrasound (CEUS) to demonstrate local tumour progression (LTP) at thermal ablation (TA) sites. METHODS: Our institutional review board approved this retrospective study; acquisition of consent was waived. Consecutive CEUS examinations performed between 2004-2014 for TA site evaluation on patients who could not undergo enhanced computed tomography (CT) or magnetic resonance imaging (MRI), or had inconclusive CT or MRI, were retrospectively reviewed. Those reported as no abnormal enhancement in or surrounding TA site were included. CEUS examination was considered true-negative based on stability or lack of enhancement/washout on follow-up imaging for at least 1 year, and false-negative (FN), if there was an arterially enhancing focus with wash-out at or surrounding TA site on subsequent follow-up imaging. RESULTS: Study population included 56 tumours in 54 patients, 11 women, 43 men; mean age 71 years. Two patients had TA of two different hepatocellular carcinomas. Thirty-six examinations were for hepatic TA and twenty for renal TA. Lesion sizes ranged from 1 cm to 7 cm (mean 3.1 ± 1.2). Mean diameter of 7 recurrences was 13.8 mm. Overall FN rate was 12.5% (7/56). Corresponding numbers were 0% (0/20) for renal TA and 19.4% (7/36) for hepatic TA. Overall NPV of CEUS was 87.5% (49/56) (confidence interval [CI]: 78.8%-96.2%). NPV for renal TA was 100% (20/20) (CI: 100%-100%) and for hepatic TA 81.5% (29/36) (CI: 67.6 %-93.5%). CONCLUSION: In this cohort, CEUS showed high NPV for exclusion of LTP at renal TA sites. NPV for hepatic TA sites was high but lower than renal TA.

Adenomyosis As a Confounder to Accurate Endometrial Cancer Staging.

The coexistence of endometrial adenocarcinoma and adenomyosis in the same uterus is a common phenomenon. In many of such affected patients foci of adenomyosis could also be colonized by adenocarcinoma. The various permutations arising from these scenarios pose preoperative imaging and postoperative pathologic staging challenges. This article aims to raise awareness of these staging issues and lists some of the relevant practical approaches. Adenomyosis reduces the accuracy of magnetic resonance imaging in assessing the depth of invasion as it reduces the contrast between the endometrial cancer adenomyosis-involved myometrium. The article also offers an alternate argument for staging cancers where myoinvasion is found deep in the myometrium, arising from cancer-positive adenomyotic foci when the surface tumor is either limited to the endometrium or to the inner half of myometrium.

Associations between quantitative evaluation of bowel wall microvascular flow by contrast-enhanced ultrasound and indices of disease activity in Crohn's disease patients using both bolus and infusion techniques.

PURPOSE: The aim is to investigate whether baseline contrast-enhanced ultrasound (CEUS) correlates with indices of activity in Crohn's disease (CD) and can predict response to medical treatment. METHODS: In this prospective study, symptomatic CD patients underwent baseline CEUS performed with Definity using both bolus and infusion methods. Time-intensity curves (TIC), peak intensity (PI), and area under curve (AUC) from a region of interest over the diseased bowel were calculated for both bolus and infusion acquisitions. We used Mann-Whitney U test for continuous and chi-square/two-tailed Fisher's exact test for categorical variable comparison and Spearman's correlation coefficient to correlate clinical score and CEUS kinetic parameters. RESULTS: Twenty-one patients (9 men, 12 women, median age 32 years) were accrued. Fifteen patients had clinically active disease defined as Harvey-Bradshaw Index (HBI) score ≥5. Median values of baseline CEUS parameters PI (bolus: 26 vs 8.86; P = .023 and perfusion: 7.6 vs 3.2; P = .009) and AUC (bolus: 769 vs 248.8; P = .036 and perfusion: 188.9 vs 73.9; P = .012) differed significantly in patients with active vs inactive disease. Nine patients with active disease underwent escalated or new treatment. Five were nonresponders. Responders had higher median values of baseline parameters (PI, bolus: 35 vs 18.8; P = .556, and perfusion: 7.6 vs 3.9; P = 190), (AUC, bolus: 1473.9 vs 314; P = .111, and perfusion: 154.7 vs 74.4, P = .286). CONCLUSIONS: CEUS kinetic parameters correlate with clinical and laboratory indices and are significantly higher in patients with active disease. The responders had higher CEUS kinetic parameters than nonresponders that did not reach statistical significance in our small cohort.

ACR Appropriateness Criteria® Clinically Suspected Adnexal Mass, No Acute Symptoms.

There are approximately 9.1 pelvic surgeries performed for every histologically confirmed adnexal malignancy in the United States, compared to 2.3 surgeries per malignancy (in oncology centers) and 5.9 surgeries per malignancy (in other centers) in Europe. An important prognostic factor in the long-term survival in patients with ovarian malignancy is the initial management by a gynecological oncologist. With high accuracy of imaging for adnexal mass characterization and consequent appropriate triage to subspecialty referral, the better use of gynecologic oncology can improve treatment outcomes. Ultrasound, including transabdominal, transvaginal, and duplex ultrasound, combined with MRI with contrast can diagnose adnexal masses as benign with specific features (ie, functional masses, dermoid, endometrioma, fibroma, pedunculated fibroid, hydrosalpinx, peritoneal inclusion cyst, Tarlov cyst), malignant, or indeterminate. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

2018 FIGO Staging System for Uterine Cervical Cancer: Enter Cross-sectional Imaging.

Imaging plays a central role in the 2018 International Federation of Gynecology and Obstetrics staging system for uterine cervical cancer. The revision calls for a more precise measurement of primary tumor size, best assessed with imaging. Evaluation for abdominopelvic retroperitoneal lymphadenopathy, either with imaging alone or with pathologic analysis, is now also part of staging. Choice of modality depends on the technology available within the practice setting. In high-resource settings, pelvic MRI (to assess tumor size and central pelvic spread) and torso fluorodeoxyglucose PET/CT (to assess lymphadenopathy and distant metastases) are used to assign stage and to plan therapy. In lower-resource settings, analogous modalities are pelvic US and chest radiography. Although imaging is already a part of pretreatment planning in some high-resource settings, its incorporation into assigning stage is a new development.

Successful Integration of Contrast-enhanced US into Routine Abdominal Imaging.

Contrast material-enhanced US is recognized increasingly as a useful tool in a wide variety of hepatic and nonhepatic applications. The modality recently was approved for limited use for liver indications in adult and pediatric patients in the United States. Contrast-enhanced US uses microbubbles of gas injected intravenously as a contrast agent to demonstrate blood flow and tissue perfusion. The growing worldwide application of contrast-enhanced US in multiple organ systems is due largely to its advantages, including high contrast resolution (sensitivity to the contrast agent), real-time imaging, lack of nephrotoxicity, the purely intravascular property of microbubble contrast agents that allows the use of disruption-replenishment techniques, and repeatability during the same examination. Through illustrative cases, common useful clinical scenarios are discussed, including characterization of liver and renal masses, especially indeterminate lesions at CT or MRI; differentiation of neoplastic cysts from nonneoplastic cysts in various organs; differentiation of tumor thrombus from bland thrombus; and assessment after a renal transplant or local ablative therapy. Common applications in the biliary system, pancreas, spleen, and vasculature also are introduced. Successful routine use of contrast-enhanced US requires an efficient setup and workflow and a thorough understanding of appropriate clinical indications and its advantages that provide added value after CT and MRI. This article familiarizes radiologists with common abdominal applications of contrast-enhanced US and guides them to implement contrast-enhanced US successfully in their clinical practice. Online supplemental material is available for this article. ©RSNA, 2018.

ACR Appropriateness Criteria® Staging and Follow-Up of Ovarian Cancer.

In the management of epithelial ovarian cancers, imaging is used for cancer detection and staging, both before and after initial treatment. The decision of whether to pursue initial cytoreductive surgery for ovarian cancer depends in part on accurate staging. Contrast-enhanced CT of the abdomen and pelvis (and chest where indicated) is the current imaging modality of choice for the initial staging evaluation of ovarian cancer. Fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT and MRI may be appropriate for problem-solving purposes, particularly when lesions are present on CT but considered indeterminate. In patients who achieve remission, clinical suspicion for relapse after treatment prompts imaging evaluation for recurrence. Contrast-enhanced CT is the modality of choice to assess the extent of recurrent disease, and fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT is also usually appropriate, as small metastatic foci may be identified. If imaging or clinical examination confirms a recurrence, the extent of disease and timing of disease recurrence then determines the choice of treatments, including surgery, chemotherapy, and radiation therapy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Negative Predictive Value of Contrast-Enhanced Ultrasound in Differentiating Avascular Solid-Appearing From Vascularized Masses: A Retrospective Consecutive Study.

OBJECTIVES: To determine the negative predictive value (NPV) of contrast-enhanced ultrasound (CEUS) to establish the lack of vascularity in a mass. METHODS: This work was an Institutional Review Board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study. Acquisition of consent was waived. We included all CEUS examinations performed for tissue characterization between 2004 and 2014 that reported showing no vascularity in a mass. Contrast-enhanced ultrasound findings were considered true-negative when there was stability on imaging for at least 1 year or no evidence of a solid mass, if biopsied, and false-negative if there was lesion growth on imaging within 12 months or an indication of a solid mass on the pathologic examination, if biopsied. One author reviewed all of the reports and follow-up examinations. We conducted a consensus review of all false-negative findings mixed with an equal number of true-negative findings by 2 reviewers, who were blinded to the final results. RESULTS: The study population consisted of 97 CEUS examinations in 97 patients, including 48 women and 49 men (mean age ± SD, 65 ± 14 years). Examinations were performed for lesion characterization in the liver (n = 23), pancreas (n = 17), kidney (n = 54), 1 gallbladder, 1 adnexa, and 1 peritoneal lesion. The overall false-negative rate on the official prospective review was 2% (2 of 97). Two false-negative findings were correctly identified on the consensus review. The NPV of CEUS was 97.9% (95 of 97; 95% confidence interval, 93%- 99%) on the official review. CONCLUSIONS: Contrast-enhanced ultrasound has a very high NPV to exclude the presence of flow in a mass, and it can be used to exclude the presence of a solid mass.

Utility of shear-wave elastography to differentiate low from advanced degrees of liver fibrosis in patients with hepatitis C virus infection of native and transplant livers.

OBJECTIVE: To determine the accuracy of shear-wave elastography (SWE) to differentiate low from advanced degrees of liver fibrosis in hepatitis C patients. MATERIAL & METHOD: Consented native/transplant hepatitis C patients underwent SWE using a C1-6 MHz transducer before ultrasound (US)-guided liver biopsy. Five interpretable SWE samples were obtained from the right lobe of the liver immediately before US-guided random biopsy of the right lobe. Average kilopascal (kPa) values were compared to the meta-analysis of histological data in viral hepatitis (METAVIR) fibrosis grading. SWE values were correlated with the degree of inflammation and fatty infiltration. RESULTS: Study population consisted of 115 patients (63 with transplant, and 52 with native liver) including 29 women and 86 men, with a mean ± SD age of 56 ± 8.7 years. Mean ± SD SWE values were 7.9 ± 3 kPa in 83 patients with METAVIR scores of 0-2 and 13.2 ± 5.9 kPa in 32 patients with METAVIR scores of 3 or 4 (P < .001). Area under curve (AUC) of a Receiver Operating Characteristics curve for advanced degrees of fibrosis was 0.81 (95% CI: 0.71, 0.90) (P < .001). AUCs of transplant versus native livers (0.78 [CI:0.62, 0.94] versus 0.85 [CI: 0.73, 0.96]), degree of inflammation (0.81 [CI: 0.65, 0.97] versus 0.72 [0.56, 0.88]), or degree of fat deposition (0.81 [CI:0.70, 0.92] versus 0.80 [CI:0.61, 1]) were not statistically different (P > .05). for kPa threshold of SWE value of 10.67 kPa to differentiate advanced from low degree of fibrosis had a sensitivity of 59% (CI: 41%-76%) and specificity of 90% (CI: 82%-96%). CONCLUSION: Liver stiffness evaluated by SWE can differentiate low from advanced liver fibrosis.

The prognostic and predictive value of vascular response parameters measured by dynamic contrast-enhanced-CT, -MRI and -US in patients with metastatic renal cell carcinoma receiving sunitinib.

OBJECTIVES: To identify dynamic contrast-enhanced (DCE) imaging parameters from MRI, CT and US that are prognostic and predictive in patients with metastatic renal cell cancer (mRCC) receiving sunitinib. METHODS: Thirty-four patients were monitored by DCE imaging on day 0 and 14 of the first course of sunitinib treatment. Additional scans were performed with DCE-US only (day 7 or 28 and 2 weeks after the treatment break). Perfusion parameters that demonstrated a significant correlation (Spearman p < 0.05) with progression-free survival (PFS) and overall survival (OS) were investigated using Cox proportional hazard models/ratios (HR) and Kaplan-Meier survival analysis. RESULTS: A higher baseline and day 14 value for Ktrans (DCE-MRI) and a lower pre-treatment vascular heterogeneity (DCE-US) were significantly associated with a longer PFS (HR, 0.62, 0.37 and 5.5, respectively). A larger per cent decrease in blood volume on day 14 (DCE-US) predicted a longer OS (HR, 1.45). We did not find significant correlations between any of the DCE-CT parameters and PFS/OS, unless a cut-off analysis was used. CONCLUSIONS: DCE-MRI, -CT and ultrasound produce complementary parameters that reflect the prognosis of patients receiving sunitinib for mRCC. Blood volume measured by DCE-US was the only parameter whose change during early anti-angiogenic therapy predicted for OS and PFS. KEY POINTS: • DCE-CT, -MRI and ultrasound are complementary modalities for monitoring anti-angiogenic therapy. • The change in blood volume measured by DCE-US was predictive of OS/PFS. • Baseline vascular heterogeneity by DCE-US has the strongest prognostic value for PFS.

Identification of Distant Metastatic Disease in Uterine Cervical and Endometrial Cancers with FDG PET/CT: Analysis from the ACRIN 6671/GOG 0233 Multicenter Trial.

Purpose To assess the accuracy of staging positron emission tomography (PET)/computed tomography (CT) in detecting distant metastasis in patients with local-regionally advanced cervical and high-risk endometrial cancer in the clinical trial by the American College of Radiology Imaging Network (ACRIN) and the Gynecology Oncology Group (GOG) (ACRIN 6671/GOG 0233) and to compare central and institutional reader performance. Materials and Methods In this prospective multicenter trial, PET/CT and clinical data were reviewed for patients enrolled in ACRIN 6671/GOG 0233. Two central readers, blinded to site read and reference standard, reviewed PET/CT images for distant metastasis. Central review was then compared with institutional point-of-care interpretation. Reference standard was pathologic and imaging follow-up. Test performance for central and site reviews of PET/CT images was calculated and receiver operating characteristic analysis was performed. Generalized estimating equations and nonparametric bootstrap procedure for clustered data were used to assess statistical significance. Results There were 153 patients with cervical cancer and 203 patients with endometrial cancer enrolled at 28 sites. Overall prevalence of distant metastasis was 13.7% (21 of 153) for cervical cancer and 11.8% (24 of 203) for endometrial cancer. Central reader PET/CT interpretation demonstrated sensitivity, specificity, positive predictive value (PPV), and negative predictive value of 54.8%, 97.7%, 79.3%, and 93.1% for cervical cancer metastasis versus 64.6%, 98.6%, 86.1%, and 95.4% for endometrial cancer, respectively. By comparison, local institutional review demonstrated sensitivity, specificity, PPV, and negative predictive value of 47.6%, 93.9%, 55.6%, and 91.9% for cervical cancer metastasis and 66.7%, 93.9%, 59.3%, and 95.5% for endometrial cancer, respectively. For central readers, the specificity and PPV of PET/CT detection of cervical and endometrial cancer metastases were all significantly higher compared with that of local institutional review (P < .05). Central reader area under the receiver operating characteristic curve (AUC) values were 0.78 and 0.89 for cervical and endometrial cancer, respectively; these were not significantly different from local institutional AUC values (0.75 and 0.84, respectively; P > .05 for both). Conclusion FDG PET/CT demonstrates high specificity and PPV for detecting distant metastasis in cervical and endometrial cancer and should be included in the staging evaluation. Blinded central review of imaging provides improved specificity and PPV for the detection of metastases and should be considered for future oncologic imaging clinical trials. © RSNA, 2017.

ACR Appropriateness Criteria® Ovarian Cancer Screening.

There has been much interest in the identification of a successful ovarian cancer screening test, in particular, one that can detect ovarian cancer at an early stage and improve survival. We reviewed the currently available data from randomized and observational trials that examine the role of imaging for ovarian cancer screening in average-risk and high-risk women. We found insufficient evidence to recommend ovarian cancer screening, when considering the imaging modality (pelvic ultrasound) and population (average-risk postmenopausal women) for which there is the greatest available published evidence; randomized controlled trials have not demonstrated a mortality benefit in this setting. Screening high-risk women using pelvic ultrasound may be appropriate in some clinical situations; however, related data are limited because large, randomized trials have not been performed in this setting. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Can the Presence of a Surrounding Endometrium Differentiate Eccentrically Located Intrauterine Pregnancy from Interstitial Ectopic Pregnancy?

OBJECTIVES: Differentiation of an eccentric intrauterine pregnancy (IUP) from an interstitial ectopic pregnancy (EP) is challenging. No sign for differentiation is reported. The purpose of this study was to determine whether the presence of surrounding endometrium (SE) can distinguish eccentric IUP from interstitial EP. METHODS: This study was approved by the institutional ethics board; consent acquisition was waived. Cases were identified using ultrasound (US) reports that included the words "interstitial," "cornual," and "angular." Blinded to official reports, one reviewer reviewed US examinations retrospectively for the presence of SE, defined as the extension of endometrial lining around the gestational sac (GS) as an indication of an eccentric IUP. US examinations without SE on the retrospective review were diagnosed as interstitial EP. RESULTS: Forty-four cases were identified from 2007 to 2015. On retrospective review, 20 cases were labeled as eccentric IUP and 24 as interstitial EP. Ten of the 20 cases retrospectively labeled as eccentric IUP had been reported and managed as eccentric IUP prospectively: four followed to a viable second trimester, and six had spontaneous abortion/termination. The remaining 10 cases retrospectively labeled eccentric IUPs because of the presence of SE had been reported and managed as interstitial EP on the official prospective report. There was follow-up suggestion of eccentric IUP in six of the latter discordant pregnancies with non-concordant retrospective and prospective diagnosis: three had hysteroscopy/curettage demonstrating retained products, two had US follow-up showing the GS moving farther down in the uterine cavity, and in one patient, the GS was shown to pass per vagina. Twenty-four of the 44 cases were called interstitial EP both on the retrospective and prospective reviews and were managed as interstitial EP. None of these patients (without SE) had follow-up suggestive of eccentric IUP. CONCLUSION: Our results suggest that the presence of surrounding endometrium around the GS allows for differentiation of eccentric IUP from interstitial EP.

Utility of PET/CT to Evaluate Retroperitoneal Lymph Node Metastasis in High-Risk Endometrial Cancer: Results of ACRIN 6671/GOG 0233 Trial.

Purpose To assess the diagnostic accuracy of fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) combined with diagnostic contrast material-enhanced computed tomography (CT) in detecting lymph node (LN) metastasis in high-risk endometrial cancer. Materials and Methods This prospective multicenter HIPAA-compliant study had institutional review board approval, and all participants gave written informed consent. Data were accrued between January 2010 and June 2013. Patients underwent PET/CT and pelvic and abdominal lymphadenectomy. Two hundred seven of 215 enrolled patients had PET/CT and pathologic examination results for the abdomen and pelvis. Mean patient age was 62.7 years ± 9.6 (standard deviation). Data in all 23 patients with a positive abdominal examination and in 26 randomly selected patients with a negative abdominal examination were used for this central reader study. Seven independent blinded readers reviewed diagnostic CT and PET/CT results in different sessions 1 month apart. Accuracy was calculated at the participant level, correlating abdominal (right and left para-aortic and common iliac) and pelvic (right and left external iliac and obturator) LN regions with pathologic results, respecting laterality. Reader-average sensitivities, specificities, and areas under the receiver operating characteristic curve (AUCs) of PET/CT and diagnostic CT were compared. Power calculation was for sensitivity and specificity in the abdomen. Results Sensitivities of PET/CT versus diagnostic CT for the detection of LN metastasis were 0.65 (95% confidence interval [CI]: 0.57, 0.72) versus 0.50 (95% CI: 0.43, 0.58) (P = .01) in the abdomen and 0.65 (95% CI: 0.57, 0.72) versus 0.48 (95% CI: 0.41, 0.56) (P = .004) in the pelvis. Corresponding specificities were 0.88 (95% CI: 0.83, 0.92) versus 0.93 (95% CI: 0.89, 0.96) (P = .11) and 0.93 (95% CI: 0.86, 0.96) versus 0.89 (95% CI: 0.82, 0.94) (P = .27), and AUCs were 0.78 (95% CI: 0.66, 0.89) versus 0.74 (95% CI: 0.63, 0.86) (P = .39) and 0.82 (95% CI: 0.71, 0.92) versus 0.73 (95% CI: 0.63, 0.84) (P = .02). Conclusion FDG PET/CT has satisfactory diagnostic accuracy in the detection of abdominal LN metastasis in high-risk endometrial cancer. Compared with diagnostic CT alone, addition of PET to diagnostic CT significantly increased sensitivity in both the abdomen and pelvis while maintaining high specificity. © RSNA, 2017 Online supplemental material is available for this article.