Diagnostic values of MRI indexes for polycystic ovary syndrome.

BACKGROUND: Magnetic resonance imaging (MRI) is a useful non-invasive modality for observation of ovarian morphologic characteristics. Few studies have focused on the value of MRI-derived indexes in reproductive-aged women with polycystic ovary syndrome (PCOS). PURPOSE: To assess the diagnostic value of MRI in women with PCOS. MATERIAL AND METHODS: This prospective case-control study included 85 women with PCOS and 50 controls who underwent pelvic MRI during 2017-2019. Ovarian volume (OV), follicle count (FC; counts of follicles sizing 2-3, 4-6, 7-9, 2-9 mm, respectively), follicular peripheral distribution, absence of a dominant follicle and stromal to total area ratio (S:A) were determined with MRI. The diagnostic value (sensitivity, specificity, area under the receiver operating characteristic curve [AUC]) of OV, FC2-9, and follicular peripheral distribution for PCOS were assessed. RESULTS: The AUCs were 0.94 for OV, 0.96 for FC2-9, and 0.78 for follicular peripheral distribution. The optimal threshold to detect PCOS was 8.5 mL for OV (sensitivity 78%; specificity 96%) and 26 for FC2-9 (sensitivity 85%; specificity 98%). Sensitivity and specificity were 73% and 82% for follicular peripheral distribution, respectively. Reproducibility was perfect for OV (ICC = 0.96) and absence of a dominant follicle (k = 0.85), substantial for FC2-9 (ICC = 0.79) and S:A (ICC = 0.69), and moderate for follicular peripheral distribution (k = 0.56). CONCLUSION: Detected by MRI, OV >8.5 mL or FC2-9 >26 are accurate for diagnosing PCOS.