O-RADS MRI scoring system: key points for correct application in inexperienced hands

Area of Science:

• Radiology
• Oncology
• Gynecologic Imaging

Background:

• Ovarian masses present diagnostic challenges, with a significant percentage of indeterminate or solid lesions requiring accurate risk stratification.
• Transvaginal ultrasound (US) can misclassify benign solid lesions as malignant, leading to potential overtreatment.

Purpose of the Study:

• To assess the efficacy of the O-RADS MRI (Ovarian-Reporting and Data System Magnetic Resonance Imaging) criteria in categorizing the malignancy risk of solid or sonographically indeterminate ovarian masses.
• To evaluate the consistency of O-RADS MRI classification between experienced and less experienced radiologists.

Main Methods:

• A retrospective analysis of 183 patients with indeterminate or solid ovarian masses who underwent MRI using a standardized O-RADS protocol.
• Two radiologists, one experienced and one less experienced in gynecologic radiology, independently classified masses using the O-RADS lexicon.
• Classification was validated against histological findings or lesion stability over time.

Main Results:

• The O-RADS MRI demonstrated excellent diagnostic performance, with sensitivity and specificity above 92% for both radiologists.
• Interobserver agreement was very high, indicated by a Kappa index of 0.92.
• Misclassifications were infrequent and primarily due to interpretation nuances, consistent with existing literature.

Conclusions:

• O-RADS MRI provides accurate risk stratification for ovarian masses, regardless of the radiologist's experience level.
• The criteria offer high diagnostic accuracy and reproducibility, supporting clinical decision-making and potentially avoiding unnecessary surgeries.
• Standardized use of O-RADS MRI and assessment tools can minimize interpretation errors.