O-RADS for assessment of adnexal lesions: current status, challenges and future directions

The Ovarian-Adnexal Reporting and Data System (O-RADS), developed by the American College of Radiology (ACR), provides a standardized, evidence-based framework for risk stratification and management of ovarian and adnexal lesions. The O-RADS system is comprised of two complementary imaging arms: ultrasound (US) and magnetic resonance imaging (MRI). O-RADS US serves as the primary imaging modality for adnexal lesion assessment, given its wide availability in outpatient and inpatient settings, relatively low cost, lack of ionizing radiation and the ability for real-time dynamic assessment. Using defined lexicon terms, lesions are stratified into five risk categories corresponding to an estimated malignancy risk with associated management recommendations. Validation studies have demonstrated high sensitivities for malignancy detection, good specificities, and strong interobserver agreement. The 2022 update refined selected descriptors to improve specificity while otherwise maintaining diagnostic performance and reproducibility, reinforcing the system's clinical utility. O-RADS MRI functions as a secondary, problem-solving tool for lesions that are technically limited or when MRI evaluation may add value. Validation studies have consistently shown excellent performance of O-RADS MRI with studies showing high specificities approaching 90-95% related to better characterization of solid tissue based on signal and dynamic enhancement characteristics. Together, O-RADS US and MRI establish a comprehensive, standardized approach that improves diagnostic confidence and optimizes patient management. Ongoing efforts focus on improving congruence between these two arms by addressing discrepancies, understanding and lowering barriers for adoption, and providing management recommendations for O-RADS MRI. Emerging evidence and evolving technologies, such as contrast-enhanced ultrasound (CEUS), quantitative imaging biomarkers and artificial intelligence (AI), may further advance the system. This review summarizes the background and validation of O-RADS US and O-RADS MRI, discusses their complementary roles, current challenges and barriers to adoption, and outlines future priorities and research directions.