The Role of Magnetic Resonance Imaging and Ultrasonography in Ovarian-Adnexal Reporting and Data System (O-Rads) For Patients Presenting With Adnexal Masses and Its Correlation With Histopathology

Abstract

Background: Adnexal masses comprise a heterogeneous spectrum of benign, borderline and malignant lesions, making accurate preoperative characterization essential for appropriate management. Ultrasonography is the primary imaging modality, while magnetic resonance imaging (MRI) provides additional characterization of indeterminate lesions. The Ovarian-Adnexal Reporting and Data System (O-RADS) provides standardized risk stratification for both ultrasound and MRI.

Methods: This hospital-based cross-sectional observational study included 50 women aged >18 years presenting with adnexal masses. All participants underwent standardized transabdominal and transvaginal ultrasonography followed by pelvic MRI. Lesions were categorized according to O-RADS USG and O-RADS MRI criteria. Histopathology was considered the reference standard wherever surgical intervention was performed. Diagnostic performance was assessed using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy.

Results: Histopathology demonstrated 36 (72%) benign, 4 (8%) borderline and 10 (20%) malignant lesions. O-RADS USG classified 32 (64%) lesions as low risk (O-RADS 2–3) and 18 (36%) as intermediate/high risk (O-RADS 4–5). O-RADS USG demonstrated 90% sensitivity, 78% specificity, 72% PPV, 92% NPV and 82% accuracy. O-RADS MRI classified 30 (60%) lesions as low risk and 20 (40%) as intermediate/high risk. MRI demonstrated superior diagnostic performance, with 95% sensitivity, 92% specificity, 86% PPV, 97% NPV and 94% accuracy. MRI improved specificity by 14 percentage points and overall accuracy by 12 percentage points compared with USG. All O-RADS 2 lesions were benign on both modalities. The combined O-RADS assessment showed 92% concordance with histopathology, with 8% discordance.

Conclusion: O-RADS ultrasonography provides effective first-line risk stratification of adnexal masses, demonstrating high sensitivity and negative predictive value. O-RADS MRI provides additional diagnostic value, particularly by improving specificity and overall accuracy in indeterminate or suspicious lesions. A sequential USG followed by MRI when clinically indicated approach can improve preoperative characterization, risk stratification and surgical planning, with strong correlation between combined imaging assessment and histopathology.