Anogenital distance on MRI does not correlate to surgical diagnosis of endometriosis in patients without prior abdominal surgery

Anogenital distance (AGD) is regarded as a potential biomarker for endometriosis, and a measurement on MRI images has been found to be promising. This study aimed to evaluate the measurement of AGD on MRI to predict the surgical diagnosis of endometriosis. We included 127 patients who received an MRI for endometriosis between October 2018 and February 2023. AGD was measured on MRI by two readers (MRI-AGD-AC: clitoris to anus; MRI-AGD-AF: posterior fourchette to anus). The feasibility and interobserver reliability of AGD measurements were evaluated. Differences in AGD between patient groups were analyzed. The intraclass correlation coefficient estimates indicated a good to excellent reliability of MRI-AGD-AC (0.92; 95% CI: 0.83-0.95) and a poor to good reliability of MRI-AGD-AF (0.68; 95% CI: 0.27-0.83). No statistically significant differences in the mean MRI-AGD-AC and MRI-AGD-AF in patients with and without surgical diagnosis of DIE (p = 0.413; p = 0.110), peritoneal endometriosis with and without DIE (p = 0.641; p = 0.323), and ovarian endometriosis (p = 0.155; p = 0.150) were found. The AUC ranged from 0.475 (95% CI: 0.365-0.584) to 0.586 (95% CI: 0.454-0.718). Thus, AGD does not constitute a valuable biomarker for patients with clinically suspected endometriosis.