To Help the Practitioner: Imaging of Ovarian Masses According to the O-RADS MRI Ovarian Malignancy Categorical Risk Scale

Objective: to study the informativity of the Ovarian-Adnexal Imaging-Reporting-Data System Magnetic Resonance Imaging (O-RADS MRI) in detection of ovarian cancer in the practice of a radiologist. Material and methods . The study included 271 women who underwent pelvic magnetic resonance imaging (MRI) in the period from August to November, 2021. Two radiologists with 6-year (Researcher 1) and 2-year (Researcher 2) experience retrospectively analyzed MR images, in which all ovarian masses were evaluated according to O-RADS MRI categorical risk scale from 0 to 5. The analysis of true positive, true negative, false positive and false negative rates according to MRI data compared to the reference data (histology or 1-year follow-up) was performed. Results. O-RADS MRI categorial risk scale had high diagnostic performance for the characterization of adnexal lesions (sensitivity 87.5% and 87.5%, specificity 97.84% and 96.75%, area under curve (AUC) 0.991 and 0.986 for Researchers 1 and 2, respectively), as well as good interreader agreement (Cohen’s kappa coefficient 0,83). Researchers’ mistakes were analyzed, as well as controversial issues of categorial affiliation of ovarian masses that caused false positive and false negative results. Visual aids for ovarian MRI in accordance with O-RADS MRI classification were made for quick orientation in the system to simplify creating the radiology report. Conclusion. O-RADS MRI categorial risk scale proved to be a reliable working tool for the communication between radiologist and gynecologist-oncologist. However, the question of categorial affiliation of a number of nosological names that are not reflected in O-RADS MRI and require further study continues to be debated.