A short anogenital distance on MRI is a marker of endometriosis

STUDY QUESTION Could the anogenital distance (AGD) as assessed by MRI (MRI-AGD) be a diagnostic tool for endometriosis? SUMMARY ANSWER A short MRI-AGD is a strong diagnostic marker of endometriosis. WHAT IS KNOWN ALREADY A short clinically assessed AGD (C-AGD) is associated with the presence of endometriosis. STUDY DESIGN, SIZE, DURATION This study is a re-analysis of previously published data from a case–control study. PARTICIPANTS/MATERIALS, SETTING, METHODS Women undergoing pelvic surgery from January 2018 to June 2019 and who had a preoperative pelvic MRI were included. C-AGD was measured at the beginning of the surgery by a different operator who was unaware of the endometriosis status. MRI-AGD was measured retrospectively by a senior radiologist who was blinded to the final diagnosis. Two measurements were made: from the posterior wall of the clitoris to the anterior edge of the anal canal (MRI-AGD-AC), and from the posterior wall of the vagina to the anterior edge of the anal canal (MRI-AGD-AF). MAIN RESULTS AND THE ROLE OF CHANCE The study compared MRI-AGD of 67 women with endometriosis to 31 without endometriosis (controls). Average MRI-AGD-AF measurements were 13.3 mm (±3.9) and 21.2 mm (±5.4) in the endometriosis and non-endometriosis groups, respectively (P