Faculty Bibliography

PURPOSE: To evaluate the utility of conventional MRI and diffusion-weighted imaging (DWI) in differentiating benign from malignant endometrial lesions. METHODS: 52 patients with an abnormal endometrium on MRI and subsequent pathologic evaluation (35 benign, 17 malignant) were included. Two radiologists (R1, R2) independently evaluated endometrial abnormalities for characteristics on conventional MRI and DWI. Findings were assessed using unpaired t-tests, Fisher's exact test, and multi-variate logistic regression. RESULTS: Findings with significantly higher frequency in malignant abnormalities were: presence of irregularly marginated endometrial lesion (R1: 71% vs. 34%, R2: 94% vs. 26%), irregular endo-myometrial interface on T2WI (R1: 77% vs. 26%, R2: 94% vs. 29%), irregular endo-myometrial interface on post-contrast T1WI (R1: 82% vs. 23%, R2: 88% vs. 20%), increased signal on high b-value DWI (R1: 82% vs. 20%, R2: 94% vs. 20%), decreased ADC (R1: 88 vs. 40%, R2: 94% vs. 20%) (all p<0.001, both readers). Endometrial thickness, presence of any focal endometrial lesion regardless of contour, diameter of endometrial lesion, endometrial heterogeneity on T2WI, decreased T2 signal, and increased endometrial enhancement, failed to show significant differences between groups (all p>/=0.159, both readers). At multivariate analysis, for R1, irregular endo-myometrial interface on post-contrast T1WI and increased DWI signal were significant independent predictors of malignancy (AUC=0.89); for R2, only increased DWI signal was a significant independent predictor of malignancy (AUC=0.87). CONCLUSION: Abnormal signal on DWI and irregularity of either the endo-myometrial interface or focal endometrial lesion were the most helpful MRI features in differentiating benign from malignant endometrial abnormalities.

Purpose To retrospectively evaluate the adherence of radiologists to the 2010 Society of Radiologists in Ultrasound (SRU) guidelines for management of adnexal cysts. Materials and Methods One radiologist reviewed the interpreting radiologists' reports for 398 adnexal cysts detected at ultrasonography in 398 patients (mean age +/- standard deviation, 41.1 years +/- 14.3; range, 18-87 years) and classified the management recommendations according to adherence to SRU guidelines. Recommendations that were not adherent were classified as overmanagement, undermanagement, or incomplete. The effects of menopausal status, cyst size and other features, and the individual interpreting radiologist on adherence were assessed by using chi(2) tests, and the association of these factors with over- and undermanagement was identified. Results Overall adherence was 59%; overmanagement, 27%; undermanagement, 9%; and incomplete, 6%. Menopausal status, cyst size, and other cyst features significantly affected adherence (P < .001). For evaluation of premenopausal patients, adherence was 63% (overmanagement, 30%) and of postmenopausal patients, 42% (undermanagement, 26%). For evaluation of cysts 1-3 cm in size, adherence was 65% (overmanagement, 21%); for cysts 3-5 cm, 33% (overmanagement, 49%); for cysts 5-7 cm, 47% (overmanagement, 20%); for cysts larger than 7 cm, 77% (over- and undermanagement, 12% each). Recommendations were adherent in most instances for corpora lutea (88%), simple cysts (56%), and cysts suggestive of benign diagnosis (60%), or with a nodule or multiple thin or thick septations (60%-100%). Cysts with recommentations for overmanagement in most instances were hemorrhagic (59%) and those with a single thin septation (67%); 31% of cysts measuring 1-7 cm in postmenopausal patients were undermanaged. Adherence varied significantly among radiologists (40%-75% adherence among radiologists who interpreted 20 or more examinations; P = .004). Conclusion Adherence to SRU guidelines for management of adnexal cysts at our institution was 59%. Overmanagement generally occurred for physiologic cysts in premenopausal patients; undermanagement was observed for simple cysts in postmenopausal patients. (c) RSNA, 2013.

Renal cell carcinoma (RCC) is most commonly diagnosed as an incidental finding on cross-sectional imaging and represents a significant clinical challenge. Although most patients have a surgically curable lesion at the time of diagnosis, the variability in the biologic behavior of the different histologic subtypes and tumor grade of RCC, together with the increasing array of management options, creates uncertainty for the optimal clinical approach to individual patients. State-of-the-art magnetic resonance imaging (MRI) provides a comprehensive assessment of renal lesions that includes multiple forms of tissue contrast as well as functional parameters, which in turn provides information that helps to address this dilemma. In this article, we review this evolving and increasingly comprehensive role of MRI in the detection, characterization, perioperative evaluation, and assessment of the treatment response of renal neoplasms. We emphasize the ability of the imaging "phenotype" of renal masses on MRI to help predict the histologic subtype, grade, and clinical behavior of RCC.

PURPOSE: To retrospectively compare perceived complexity and Bosniak cyst classification of cystic renal lesions between 1.5T and 3T MRI. METHODS: 33 cystic renal lesions in 26 patients that underwent contrast-enhanced MRI at both 1.5T and 3T within a 12 month span were included. Two radiologists (R1, R2) independently assessed lesions, unaware of field strength, in terms of number of septations, septal thickening, mural thickening, presence of mural nodule, and Bosniak cyst category. Scores were compared between field strengths for each lesion. RESULTS: R1 observed increases in septal number, septal thickening, mural thickening, and presence of mural nodule at 3T in 8, 7, 4, and 2 lesions, and at 1.5T in 3, 3, 2, and 0 lesions, respectively; R2 observed increases in septal number, septal thickening, mural thickening, and presence of mural nodule at 3T in 3, 4, 3, and 0 lesions, and at 1.5T in 2, 0, 0, and 0 lesions, respectively. R1 provided higher Bosniak category at 3T in 9 cases and at 1.5T in 4 cases; R2 provided higher Bosniak category at 3T in 4 cases and at 1.5T in 0 cases. Higher scores at 3T than 1.5T were associated with differences in advised clinical management in 7/9 cases for R1 and 4/4 cases for R2. CONCLUSION: There was an overall tendency for both readers to upgrade cyst complexity and Bosniak cyst category at 3T than 1.5T, which impacted advised management. Thus, we suggest that serial MRI evaluation of cystic renal lesions be performed at constant field strength.

Gadoxetic acid-enhanced magnetic resonance cholangiopancreatography (MRCP) was performed for evaluation of living donor liver transplantation. T2-weighted MRCP and hepatobiliary-phase postcontrast MRCP showed an aberrant right posterior bile duct, although the precise variant was uncertain. Optimized hepatobiliary-phase MRCP was obtained using 3 sequence modifications: increased flip angle to improve contrast between the biliary tree and surrounding tissues; radial k-space sampling to minimize motion artifact; and free-breathing acquisition to improve signal-to-noise ratio and, in turn, spatial resolution (resolution of 1.28 x 1.28 x 1.5 mm). The optimized sequence demonstrated that the right posterior bile duct drained into the cystic duct, consistent with type 3C biliary variant, thus modifying surgical planning.

INTRODUCTION: To assess impact of size of regions-of-interest (ROI) on differentiation of RCC and renal cysts using multi-phase CT, with focus on differentiating papillary RCC (pRCC) and cysts given known hypovascularity of pRCC. METHODS: 99 renal lesions (23 pRCC, 47 clear-cell RCC, 7 chromophobe RCC, 22 cysts) underwent multi-phase CT. Subjective presence of visual enhancement was recorded for each lesion. Whole-lesion (WL) ROIs, and small (