MRI-based risk stratification of adnexal lesions: comparative diagnostic performance of O-RADS, ADNEX-MR and modified ADNEX-MR scoring systems

Purpose To standardize the interpretation of adnexal lesions, several magnetic resonance imaging (MRI)-based scoring systems have been developed, including the Ovarian-Adnexal Reporting and Data System (O-RADS), the ADNEX-MR score, and the modified ADNEX-MR score. The aim of this study was to compare the diagnostic performance of the standard ADNEX-MR score, the O-RADS MRI system, and the modified ADNEX-MR score in the characterization of adnexal masses, using histopathological diagnosis as the reference standard. Materials and methods A prospective cross-sectional study included 70 females with 88 adnexal masses. All patients underwent conventional pelvic MRI with diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE). Each lesion was classified according to the O-RADS MRI system and both classical and modified ADNEX-MR scoring systems. Results The standard ADNEX-MR score demonstrated excellent diagnostic performance, with high sensitivity (91.2%) and specificity (97.1%). The O-RADS MRI system showed comparable results, with similar sensitivity (91%) and slightly lower specificity (94%). The modified ADNEX-MR score, which incorporates diffusion-weighted imaging as an essential parameter, achieved higher sensitivity (95%) and lower specificity (80%). Conclusion The ADNEX-MR and O-RADS MRI systems demonstrated high and balanced diagnostic performance for adnexal lesion characterization. The modified ADNEX-MR score improved sensitivity and negative predictive value, enhancing malignancy detection, particularly in indeterminate cases or when DCE MRI is unavailable, albeit at the expense of reduced specificity.