Diagnostic Performances of Tridimensional Rectosonography and Magnetic Resonance Imaging in Rectosigmoid Endometriosis: A Prospective Cohort Study on 101 Patients.

Abstract

Tridimensional rectosonography (3-D RSG) is a transvaginal ultrasonography procedure combining intrarectal contrast with tridimensional technology. The objectives of this study were to assess the diagnostic performances of 3-D RSG in deep infiltrating rectosigmoid endometriosis using surgery and pathology as the gold standard, and to compare its results with those of magnetic resonance imaging (MRI). Patients referred for endometriosis with symptoms suggesting deep infiltrating intestinal endometriosis (DIE) were included if they agreed to undergo a 3-D RSG and MRI and if there was a surgical indication related to endometriosis. The study was a non-randomized monocentric prospective cohort study (Canadian task force classification Level II-2). From May 2012 to May 2017, 101 patients were included. Sixty patients (59.4%) had bowel involvement of the rectum (n\u202f=\u202f21, 20.8%) or of the sigmoid (n\u202f=\u202f39, 38.6%) confirmed in surgery and/or in pathologic testing. In the diagnosis of rectosigmoid DIE, 3-D RSG sensitivity, specificity, positive predictive value, negative predictive value, accuracy and κ index were 93%, 95%, 97%, 91%, 94% and 0.88, respectively. For MRI they were 87%, 90%, 93%, 82%, 88% and 0.76, respectively. The accuracy was not significantly different between 3-D RSG and MRI (p\u202f=\u202f0.181). In conclusion, 3-D RSG is an effective technique to diagnose rectosigmoid endometriosis and seems to have similar diagnostic performances to MRI for this indication.