Faculty Bibliography

AIM: To evaluate the performance of multidetector computed tomography (MDCT) in the measurement of endometrial thickness and assessment for endometrial disease. MATERIALS AND METHODS: Seventy-nine MDCT examinations, including sagittal reformats from isotropic data, were retrospectively evaluated for the presence of endometrial abnormality, endometrial thickness, and recommendation for transvaginal ultrasound (TVUS) after CT. The endometrial thickness was measured on sagittal images using two different methods, between the inner-to-inner hypoattenuating stripe, and when visible, between the outer-to-outer hyperattenuating stripe. TVUS performed within 48 h of CT in premenopausal and 1 month in postmenopausal patients served as reference standard. Interobserver agreement for endometrial thickness and abnormalities was assessed using concordance correlation (CC) and kappa statistics. RESULTS: Interobserver agreement for endometrial thickness on sagittal CT images was excellent (CC 0.98), and highly accurate using the inner-to-inner measurement. For determination of abnormal thickening, the positive predictive value and negative predictive value were 67-100% and 99.5-100%. For detection of any endometrial abnormality, the positive predictive value and negative predictive value were 79-90% and 84-95%, respectively. False-negative missed abnormalities included small volume hydrometra, a polyp, and endometrial distortion by a fibroid. CONCLUSION: At MDCT, sagittal reformatted images provide reliable endometrial measurement using the inner-to-inner hypoattenuating stripe and are accurately categorized as normal or abnormal thickness using the same numerical criteria as at sonography.

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.

AIM: To retrospectively evaluate the prevalence of pelvic organ prolapse as an incidental finding on dynamic magnetic resonance imaging (MRI) using two different references lines. MATERIALS AND METHODS: Sixty women with symptoms unrelated to pelvic floor dysfunction who underwent MRI including a dynamic sagittal true fast imaging with steady-state free precession (TrueFISP) sequence during straining were identified. Two radiologists in consensus used the pubococcygeal line (PCL) and mid-pubic line (MPL) to diagnose and grade prolapse in all three pelvic compartments. RESULTS: Cystocele was absent, mild, moderate, and severe in 88% (53/60), 7% (4/60), 5% (3/60), and 0% (0/60) of patients, respectively, using PCL, versus 78% (47/60), 13% (8/60), 5% (3/60), and 3% (2/60) of patients, respectively, using MPL. Vaginal prolapse was absent, mild, moderate, and severe in 95% (57/60), 5% (3/60), 0% (0/60), and 0% (0/60) of patients, respectively, using PCL, versus 80% (48/60), 17% (10/60), 3% (2/60), and 0% (0/60) of patients, respectively, using MPL. Rectal descent was absent, mild, moderate, and severe in 63% (38/60), 10% (6/60), 23% (14/60), and 3% (2/60) of patients, respectively, using PCL, versus 43% (26/60), 27% (16/60), 27% (16/60), and 3% (2/60) of patients, respectively, using MPL. No enterocele, peritoneocele, or muscular defect was identified. Two percent (1/60) of patients had mild rectocele, 8% (5/60) had abnormal vesico-urethral angle, and 25% (15/60) had abnormal levator plate angle. CONCLUSION: In asymptomatic women, dynamic MRI identified the greatest degrees of prolapse in the posterior compartment. The MPL consistently yielded greater frequency of prolapse than the PCL. Findings of pelvic organ prolapse may be observed in asymptomatic patients and are of uncertain significance, requiring correlation with clinical and physical examination findings.

Imaging is used to detect and characterize adnexal masses and to stage ovarian cancer both before and after initial treatment, although the role for imaging in screening for ovarian cancer has not been established. CT and MRI have been used to determine the resectability of tumors, the candidacy of patients for effective cytoreductive surgery, the need for postoperative chemotherapy if debulking is suboptimal, and the need for referral to a gynecologic oncologist. Radiographic studies such as contrast enema and urography have been replaced by CT and other cross-sectional imaging for staging ovarian cancer. Contrast-enhanced CT is the procedure of choice for preoperative staging of ovarian cancer. MRI without and with contrast may be useful after equivocal CT, but is usually not the best initial procedure for ovarian cancer staging. Fluorine-18-2-fluoro-2-deoxy-D-glucose-PET/CT may not be needed preoperatively, but its use is appropriate for detecting and defining post-treatment recurrence. Ultrasound is useful for evaluating adnexal disease, but has limited utility for staging ovarian cancer. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

PURPOSE: To establish the utility of apparent diffusion coefficient (ADC) entropy in discrimination of benign and malignant adnexal lesions, using histopathology as the reference standard, via comparison of the diagnostic performance of ADC entropy with mean ADC and with visual assessments of adnexal lesions on conventional and diffusion-weighted sequences. MATERIALS AND METHODS: In all, 37 adult female patients with an ovarian mass that was resected between June 2006 and January 2011 were included. Volume-of-interest was drawn to incorporate all lesion voxels on every slice that included the mass on the ADC map, from which whole-lesion mean ADC and ADC entropy were calculated. Two independent radiologists also rated each lesion as benign or malignant based on visual assessment of all sequences. The Mann-Whitney test and logistic regression for correlated data were used to compare performance of mean ADC, ADC entropy, and the visual assessments. RESULTS: No statistically significant difference was observed in mean ADC between benign and malignant adnexal lesions (P = 0.768). ADC entropy was significantly higher in malignant than in benign lesions (P = 0.009). Accuracy was significantly greater for ADC entropy than for mean ADC (0.018). ADC entropy and visual assessment by the less-experienced reader showed similar accuracy (P >/= 0.204). The more experienced reader's accuracy was significantly greater than that of all other assessments (P