Preoperative Imaging in Patients with Deep Infiltrating Endometriosis (DIE): An Important aid in Predicting Depth of Infiltration in Rectosigmoid Disease.

Abstract

To determine the diagnostic accuracy of specialist transvaginal ultrasound (TVUS) and pelvic magnetic resonance imaging (MRI) modalities in predicting depth of deep infiltrating endometriosis (DIE) of the rectosigmoid by comparison with histological specimens obtained at surgery. A retrospective analysis, which met the STARD (2015) guidelines for a diagnostic accuracy study. Tertiary teaching hospital. 194 cases who underwent preoperative discussion at the Gynaecological Endosurgery Unit multidisciplinary meeting (MDM) between January 2012 and December 2019 were eligible for inclusion. Retrospective assessment of the accuracy of TVUS and MRI in predicting histological depth of rectosigmoid DIE following operative management. 135 surgeries were performed for DIE; 20 underwent a rectal shave, 14 had a disc/wedge resection, 38 an anterior/segmental resection, 63 had no rectosigmoid surgery. Of the 52 patients with full thickness rectal wall excision, all patients had at least one imaging modality available for review; 42 (81%) had both. At least one imaging modality was in agreement with histological depth in 48 (92%) cases (sensitivity 94%, specificity 50%, positive predictive values (PPV) 97.9%, negative predictive value (NPV) 25.0%; area under the receiver operating curves (AUROC) 0.720, 95%CI: 0.229, 1.000). When TVUS was assessed in isolation, the test remained sensitive for any rectal wall involvement (sensitivity 93.6%, specificity 50.0%, PPV 97.8%, NPV 25.0%; AUROC 0.718, 95%CI: 0.227, 1.000). When only MRI was assessed, the test demonstrated both high sensitivity and specificity for rectal wall disease (sensitivity 86.4%, specificity 100%, PPV 100%, NPV 14.2). Specialised performed TVUS and MRI are accurate in predicting depth of disease in rectosigmoid endometriosis. These modalities were similar in their diagnostic performance at assessing depth of rectal wall involvement and their use is justified in the preoperative planning of these gynaecological surgeries.