Magnetic Resonance Rectal Enema Versus Computed Tomographic Colonography in the Diagnosis of Rectosigmoid Endometriosis

OBJECTIVES: Rectosigmoid involvement by endometriosis causes intestinal symptoms such as constipation, diarrhea, and dyschezia. A precise diagnosis about the presence, location, and extent of bowel implants is required to plan the most appropriate treatment. The aim of the study was to compare the accuracy of magnetic resonance with distension of the rectosigmoid (MR-e) with computed colonography (CTC) for diagnosing rectosigmoid endometriosis. METHODS: This study was based on the retrospective analysis of a prospectively collected database of patients with suspicion of rectosigmoid endometriosis who underwent both MR-e and CTC, and subsequently were treated by laparoscopy. The findings of imaging techniques were compared with surgical and histological results. RESULTS: Of 90 women included in the study, 44 (48.9%) had rectosigmoid nodules and underwent bowel surgery. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for the diagnosis of rectosigmoid endometriosis were 88.6%, 93.5%, 92.9%, 89.6%, and 91.1% for CTC, and 93.2%, 97.9%, 97.6%, 93.8%, and 95.6% for MR-e. There was no significant difference in the accuracy of both radiologic examinations for diagnosing rectosigmoid endometriosis (P = 0.344). However, MR-e was more accurate than CTC in estimating the largest diameter of the main rectosigmoid nodule (P < 0.001). The pain perceived by the patients was significantly lower during MR-e than during CTC (P < 0.001). CONCLUSIONS: MR-e and CTC have similar diagnostic performance for the diagnosis of rectosigmoid involvement of endometriosis. However, MR-e is more accurate in the estimation of the largest diameter of main rectosigmoid nodule and more tolerated than CTC.