36: Correlation of endometriosis on preoperative MRI and surgical pathology

Abstract

The aim of this study is to assess whether the use of MRI as part of preoperative workup in the setting of patients with chronic pelvic pain and presumed diagnosis of endometriosis is predictive of pathology-proven endometriosis. Retrospective chart review of patients operated on by one fellowship trained minimally invasive gynecologist over the course of 16 months was completed. All surgical cases performed at one of two tertiary hospitals between November 2017 and February 2019 were reviewed and laparoscopic cases were identified. Laparoscopic cases in which a preoperative MRI was performed were then identified. These cases were reviewed to assess for presence or absence of: (1) a preoperative prediction of endometriosis, (2) identification of endometriosis on preoperative MRI, and (3) surgical diagnosis of endometriosis based on intraoperative findings or surgical pathology. 25 surgical cases had MRI performed preoperatively. 10 predicted endometriosis preoperatively and all had pathology confirmed endometriosis. Of the patients with positive MRIs and positive pathology for endometriosis, 5(50%) were stage 4, 3(30%) stage 3, 1(10%) stage 2, and 1(10%) stage 1. Of the 15 of the preoperative MRIs that did not predict endometriosis, 7 had pathology confirmed endometriosis and 8 were pathology confirmed negative for endometriosis. Of the patients with negative MRIs and positive pathology for endometriosis, 4(57.1%) were stage 1, 2(28.6%) stage 2, and 1(14.3%) stage 3. A Fisher exact test for equality of accuracy in the patients showed that patients who had a positive MRI had a significantly higher endometriosis pathologic diagnosis accuracy than patients who had a negative MRI (p<0.05). Ultrasound is the most common form of imaging done in the setting of suspected endometriosis. The advanced dynamic ultrasound techniques in the literature for endometriosis assessment is not universally available in the US. Preoperative MRI may be used as part of the workup of patients with presumed endometriosis because it allows for evaluation of all pelvic compartments as well as increased accuracy in suspected diagnosis. MRI is also less susceptible to interobserver variability that can be associated with ultrasound, which is dependent on the technician and the radiologist. Preoperative MRI was predictive for both presence and absence of endometriosis. The MRI was more predictive of advanced stage endometriosis. Advanced disease endometriosis is best treated by a surgeon with advanced surgical skills and experience with endometriosis so that the patient has clear expectations of outcomes and recurrence, to optimize resection, to minimize complications, and to reduce need for repeat surgery due to inadequate resection.