OC26.02: Does bowel preparation affect the performance of transvaginal ultrasonography in the diagnosis of rectosigmoid endometriosis?

This study investigates whether bowel preparation (BP) influences the performance of transvaginal ultrasonography (TVS) in the diagnosis of rectosigmoid endometriosis. This prospective study included 214 patients who were referred to our institution because of suspicion of deep endometriosis and underwent laparoscopy. TVS without BP was performed at the time of the first consultation at our institution. Patients underwent a second transvaginal ultrasonography after BP (rectal enema) within 45 days from the first consultation; this exam was performed by a physician blinded to the findings of the first TVS. The results of the two exams were compared with surgical findings and histology. The mean (± SD) age of the study population was 32.2 ± 4.6 years. At the time of the study, 115 patients (53.7%) were under hormonal therapies. 103 patients (48.1%) had rectosigmoid endometriosis at surgery. The McNemar's test showed that TVS without BP had similar performance in the diagnosis of rectosigmoid endometriosis than TVS with BP (p = 0.134). The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio of TVS with and without BP were respectively 93.2% (95%CI, 86.5%-97.2%), 95.5% (89.8%-98.5%), 95.1% (88.8%-98.4%), 93.8% (87.7%-97.5%), 20.7 (8.8-48.8), 0.1 (0.1-0.2) and 90.3% (82.9%-95.3%), 94.6% (88.6%-98.0%), 93.9% (87.3%-97.7%), 91.3% (84.6%-95.8%), 16.7 (7.7-36.5), 0.10 (0.1-0.2). There was no significant difference in the accuracy of TVS with and without BP in estimating the largest diameter of the intestinal nodule, in diagnosing multifocal disease and in estimating the distance between endometriotic bowel nodules and the anus. BP does not improve the performance of TVS in diagnosing rectosigmoid endometriosis.