Anatomical localization of deep infiltrating endometriosis: 3D MRI reconstructions

The goal of this study was to determine the accuracy of three-dimensional (3D) MRI reconstructions obtained with segmentation technique in the preoperative assessment of deep infiltrating endometriosis (DIE) and in particular to evaluate rectosigmoid and bladder wall involvement. Institutional review board approval for this study was obtained, and each patient gave written informed consent. Fifty-seven consecutive patients with diagnosis of DIE who had undergone pelvic MRI at 1.5 T before surgery between 2007 and 2011, were retrospectively evaluated and 3D post-processed in order to obtain a detailed mapping of DIE. A blinded reader interpreted images. MRI results were compared with surgical findings and were scored by using a four-point scale (0_3 score). 36/57 patients with symptomatic DIE underwent surgery: 18/36 had endometriotic nodules infiltrating the rectouterine pouch, 12/36 the vesicouterine pouch, and 6/36 the rectovaginal pouch. The sensitivity of MRI and 3D MRI vs. surgery was, respectively, 64% vs. 83%; diagnostic accuracy of 3D MRI respect to MRI alone was 86% vs. 67% for localization; 86% vs. 67% for dimension; 79% vs. 58% for rectosigmoid infiltration; 92% vs. 75% for bladder infiltration. In this preliminary study, 3D MRI reconstructions obtained with semi-automatic method of segmentation provided encouraging results for staging DIE preoperatively. In fact, the addition of 3D MRI reconstructions improved diagnostic accuracy and staging of DIE providing the exact volume of the lesions and enabling a precise mapping of these before surgery.