OC16.01: Magnetic resonance enema versus rectal water contrast transvaginal ultrasonography in the diagnosis of rectosigmoid endometriosis

To compare the accuracy of magnetic resonance enema (MR-e) and transvaginal ultrasonography combined with water-contrast in the rectum (RWC-TVS) in diagnosing rectosigmoid endometriotic nodules. This was a prospective cross-sectional study. Inclusion criteria for the study were: reproductive age, suspicion of deep pelvic endometriosis on the basis of symptoms and vaginal examination, presence of gastrointestinal symptoms. The radiologist performing MR-e and the ultrasonographer performing RWC-TVS were blinded to the results of the other investigation. Patients underwent laparoscopy within 3 months from the diagnostic procedures. Radiological and ultrasonographic findings were compared with surgery and histology. Out of 286 women included in the study, 151 had rectosigmoid endometriotic nodules (52.8%). The sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio positive and likelihood ratio negative of MR-e and RWC-TVS in the diagnosis of recto-sigmoid endometriosis were 95.36% (95%C.I.,90.68%–99.11%), 97.78% (93.63%–99.51%), 97.96% (94.14%–99.55%), 94.96% (89.89%–97.94%), 42.91 (14.01–131.46), 0.05 (0.02–0.10) and 92.72% (87.34%–96.30%), 97.04% (92.58%–99.17%), 97.22% (93.03%–99.22%), 92.25% (86.56%–96.06%), 31.29 (11.90–82.25), 0.08 (0.04–0.13), respectively. There was no significant difference in the accuracy of the two techniques in the diagnosis of rectosigmoid endometriosis (p = 0.063; McNemar's test). RWC-TVS was more accurate than MR-e in estimating the degree of stenosis of the bowel lumen (p < 0.05) and the depth of infiltration of endometriosis in the bowel wall (p < 0.01). There was no significant difference in the intensity of pain experienced by the patients during the two exams. RWC-TVS is as accurate as MR-e in the diagnosis of rectosigmoid endometriosis and it should be the first line investigation in patients with clinical suspicion of rectosigmoid endometriosis.