EP23.17: Ovarian‐Adnexal Reporting and Data System magnetic resonance imaging score in evaluating sonographically indeterminate adnexal masses

To validate the accuracy of a 5-point Ovarian-Adnexal Reporting and Data System Magnetic Resonance Imaging (O-RADS MRI) score for evaluation of indeterminate adnexal masses. 66 female patients with 79 indeterminate adnexal lesions by US, did MRI with protocol including conventional MR sequences, Diffusion Weighted Imaging (DWI) with different b values and Dynamic images using T1High-Resolution Isotropic Volume Examination. All patients underwent surgical interference and radiological diagnosis was correlated with pathological results. A significant difference was found between malignant and benign groups regarding the ORADS score. No malignant lesions had O-RADS 2 score and no benign lesions had 5 O-RADS score. A large number of benign lesions were categorised as O-RADS 3 (81.8%) and most of malignant cases were categorised O-RADS 4&5. The sensitivity, specificity and overall diagnostic accuracy were 97.8, 90.9 and 94.9% respectively. The predominantly cystic lesions showed a statistically significant difference between malignant and benign cases with a larger proportion of benign cases being predominantly cystic. The T2 signal (SI) of the solid component demonstrated a significant difference between malignant and benign cases. All the lesions that displayed low T2 SI were benign, while all malignant cases (100%) exhibited intermediate T2 SI. The DWIs showed a highly significant difference between malignant and benign cases with most malignant cases exhibiting restricted diffusion. The dynamic curve patterns demonstrated a highly significant difference between malignant and benign cases. A considerable proportion of malignant cases (52.2%) exhibited curve 3, while a substantial number of benign cases (90.9%) displayed curve 1. The O-RADS MRI score should be used as a reliable diagnostic tool for detecting malignancy in indeterminate adnexal masses. Its accuracy can provide valuable information and assist appropriate clinical management.