Bowel endometriosis: preoperative diagnostic accuracy of 3.0-T MR enterography--initial results.

PURPOSE: To prospectively determine the accuracy of 3.0-T magnetic resonance (MR) enterography in the preoperative assessment of deep infiltrating endometriosis (DIE) lesions located in the bowel above the rectosigmoid junction.
MATERIALS AND METHODS: Institutional review board approval for this study was obtained, and each patient gave written informed consent. Over 18 months, patients with known pelvic DIE who were scheduled for surgery were recruited. Consecutive patients suspected of having bowel endometriosis above the rectosigmoid junction underwent 3.0-T MR enterography. Two blinded readers independently performed a systematic analysis of nine bowel segments above the rectosigmoid junction. MR images were compared with surgical and pathologic findings. Efficacy parameters were calculated with 95% confidence intervals (CIs). Interobserver agreement was assessed with κ statistics.
RESULTS: Among the 43 patients enrolled in this study, 33 underwent surgery and were included in the final analyses. Sixteen (48%) patients had bowel DIE lesions located above the rectosigmoid junction at surgery and histopathologic examination. Twenty-six lesions were analyzed, including four ileal, two ileocecal, three cecal, three appendicular, and 14 sigmoid colon lesions. For the diagnosis of these lesions, MR imaging showed sensitivities of 92% (95% confidence interval [CI]: 81.7, 100) for reader 1 and 96% (95% CI: 87.1, 100) for reader 2 and specificities of 100% (95% CI: 98.8, 100) for both readers. The κ value was 0.97.
CONCLUSION: These results show 3.0-T MR enterography is accurate in the preoperative diagnosis and mapping of bowel DIE lesions located above the rectosigmoid junction. Online supplemental material is available for this article. © RSNA, 2014.