Comparison of magnetic resonance imaging findings with and without intravenous contrast in women with pelvic endometriosis: A cross-sectional study.

Background: Endometriosis is a common disease of the female genital system. Pelvic magnetic resonance imaging (MRI) is the best non-invasive diagnostic method for evaluating endometriosis. Objective: This study aims to compare the findings of MRI with and without intravenous (IV) contrast in participants with endometriosis. Materials and Methods: This cross-sectional study was conducted on 100 women of reproductive age with endometriosis at gynecology clinics of 22 Bahman and Ghaem hospital, Mashhad, Iran from April 2021-July 2023. All participants underwent pelvic MRI with and without IV contrast. The imaging findings of each participant were recorded in the study checklist. Vaginal and rectal gels were applied prior to imaging to improve anatomical delineation. Results: 72% of the participants were aged between 26 and 40 yr. History of infertility was positive in 42% of the individuals. The frequency of ovarian endometrioma detection and its mean size before and after contrast injection did not show a significant difference. The mean depth of rectosigmoid wall and posterior uterine wall endometriosis was significantly higher in images with IV contrast than in images without IV (p = 0.026 and 0.04, respectively). Conversely, the detection of deep infiltrating endometriosis (DIE) in uterosacral ligaments and torus uterus was significantly higher in pre-contrast MRI (p = 0.016). Conclusion: In cases with DIE in the rectal and posterior walls of the uterus, MRI with IV contrast is more accurate in the detection of the disease extent. DIE in the uterosacral ligaments and torus uterus is better detected in MRI without IV contrast.