Assessment of the O-RADS scoring system for the differentiation of different types of ovarian neoplasms: A modified approach with non-DCE-MRI

Purpose: The O-RADS MRI score stratifies adnexal mass risk with characteristics of T1-weighted, T2-weighed and dynamic contrast-enhanced (DCE) images. We explored a modified approach to evaluate the value of incorporation DWI/ADC with non-DCE-MRI in ORADS scoring system, and to assess the diagnostic performance and interreader consistency in differentiating ovarian neoplasm with different types. Methods: This retrospective study included 218 women who underwent pelvic MRI with 221 ovarian tumors between January 2017 and December 2021. Two radiologists independently assessed each lesion using the original and modified O-RADS approach (incorporating DWI/ADC with non-DCE). Cohen's weighted-kappa and ROC analyses were employed to assess interreader consistency and diagnostic efficiency across all lesions and three ovarian neoplasms categories. Results: The area under the ROC curve (AUC) of the original protocol was 0.945 for all lesions and 0.947, 0.992, and 0.758 for the epithelial cell, germ cell and sex cord-stromal neoplasms. The modified approach achieved AUCs of 0.959 for all lesions and 0.962, 0.997, and 0.837 for the three categories. The interreader agreement was 'excellent' for all lesions and 'good' for the subgroups with the original protocol, improving to 'excellent' for all categories with the modified approach. Conclusion: A modified O-RADS incorporating DWI/ADC with non-DCE MRI yields high diagnostic performance in differentiation of different types of ovarian neoplasms. It further improves consistency in subgroup interpretation. The modified approach can serve as an effective diagnostic tool without DCE, further promoting its adoption in primary hospitals.