MRI of pediatric ovarian masses: validation of the O-RADS framework

Objective: The purpose of our study was to test the applicability and implications of using the O-RADS system, which is developed and validated on adults, to review MRI of ovarian masses among pediatric patients. Materials and methods: We retrospectively reviewed consecutive MRI examinations from pediatric patients referred to imaging for suspected ovarian lesions, assessing them using the O-RADS framework. Malignancy frequencies among O-RADS classes were reviewed, and we appraised the potential for such approach to split patients into low (O-RADS 1, 2, and 3) and high risk (O-RADS 4 and 5). Multivariate analyses were conducted to review which clinical or imaging variables yielded a significant impact on malignancy, and a simplified reading framework was proposed accordingly. Results: 109 female patients were included, with a median age of 13 years (IQR 11–15 years), 7 (7%) presenting with malignant lesions. Malignancy proportions were 0% (95% confidence Interval (CI) 0–35%) for the O-RADS 1 class, 0% (95% CI 0 − 5%) for the O-RADS 2 class, 0% (95% CI 0–14%) for the O-RADS 3 class, 50 (95% CI 1 − 99%) for the O-RADS 4 class, and 75% (95% CI 41–93%) for the O-RADS 5 class. The presence of peritoneal thickening or nodules (p < 0.001), lesion composition (p < 0.001), and absence of intralesional fat (p = 0.051) were individual predictors of malignancy, and the simplified reading framework proposed with such variables identified 11 likely malignant cases, detecting all 7 malignant lesions. Conclusion: The O-RADS system may be applied to MRI performed in the pediatric population for ovarian masses, and a simplified reading framework based on O-RADS could also prove useful in such a setting. Key Points: Question The Ovarian-Adnexal Reporting and Data System (O-RADS) provides the risk of malignancy of ovarian masses among adults but has not been validated among pediatric patients. Findings Malignancy frequencies for O-RADS classes 1, 2, 3, and 4 were 0, 0, 50%, and 75%, indicating a good accuracy in lesion discrimination. Clinical relevance The Ovarian-Adnexal Reporting and Data System (O-RADS) can be effectively applied to MRI examinations in pediatric patients, enabling accurate classification of findings, with potential for score simplification in this age group.