OC16.06: The role of bowel preparation prior to ultrasound to detect and assess deep endometriotic nodules on rectal wall

To evaluate the benefit of bowel preparation (BP) before a transvaginal ultrasound (TVUS) to detect and describe nodules of deep infiltrating endometriosis (DIE) affecting the anterior rectal wall. The rectal wall of patients with suspected endometriosis was evaluated by TVUS. All patients were explored twice. First ultrasound was performed without a previous BP and the second, just after three-day low-residue diet and two enemas of 250 ml (12 h and 3 h before TVUS). A total of 53 patients were included in the study. Eight of them showed spontaneous bowel emptying in the first TVUS and were excluded. Nodules were observed in 17 patients (38%) without BP and in 22 (49%) patients after BP. A total of 12 nodules were observed after bowel emptying, not detected without BP (one nodule more each 3.75 patients assessed; p = 0.03). In the population studied, the nodules measured 30.9 ± 15.0 mm long and 9.0 ± 2.6 mm deep on average without BP. After BP, nodules measurements had an average of 40.0 ± 12.6 mm and 10.8 ± 1.5 mm respectively. Furthermore, other parameters such as rectum circumference affected, number of affected layers and distance from anus are more frequently evaluable (p < 0.001) if BP is used prior to TVUS (98% vs. 64%; 100% vs. 67%; 100% vs. 73% respectively). TVUS with BP permits to detect more rectal nodules of DIE in patients with suspected endometriosis. The nodules seem longer and deeper after BP and other ultrasound parameters are more frequently evaluable.