ADDED VALUE OF QUANTITATIVE ANALYSIS OF DWI/ADC IN OVARIAN ADNEXAL REPORTING AND DATA SYSTEM MRI

Background: Adnexal masses are among the most frequent gynecological findings, with ultrasound being the primary imaging tool for their initial evaluation. Although ultrasonography reliably classifies many adnexal lesions, up to 31% remain indeterminate, posing diagnostic and management challenges. Magnetic Resonance Imaging (MRI) with the Ovarian-Adnexal Reporting and Data System (O-RADS) has been introduced as a standardized approach to improve lesion characterization, reduce unnecessary interventions, and enhance patient outcomes. Objective: This study aimed to evaluate the diagnostic accuracy of MRI using the O-RADS classification system in characterizing adnexal masses indeterminate on ultrasonography, with histopathology serving as the gold standard. Methods: A prospective, observational study was conducted at the Armed Forces Institute of Radiology and Imaging (AFIRI), Rawalpindi, over six months. A total of 150 female patients aged 18–65 years with indeterminate adnexal masses based on IOTA Simple Rules or similar ultrasound scoring systems were enrolled using consecutive sampling. All patients underwent pelvic MRI with contrast, and lesions were categorized using the O-RADS MRI scoring system. Surgical excision followed by histopathological examination provided the definitive diagnosis. Statistical analysis was performed using SPSS version 21. Sensitivity, specificity, predictive values, and overall diagnostic accuracy were calculated, and Receiver Operating Characteristic (ROC) curve analysis was used to evaluate performance. Results: The mean age of participants was 42.6 ± 10.8 years, with 87 (58.0%) premenopausal and 63 (42.0%) postmenopausal. Pelvic pain was the most common presenting symptom, reported in 87 patients (58.0%). MRI categorized lesions as O-RADS 2 in 26 patients (17.3%), O-RADS 3 in 47 (31.3%), O-RADS 4 in 38 (25.3%), and O-RADS 5 in 39 (26.0%). Histopathology confirmed 42 malignant cases (28.0%) and 108 benign cases (72.0%). Using O-RADS ≥4 as the threshold for malignancy, MRI demonstrated a sensitivity of 88.1%, specificity of 63.0%, positive predictive value of 48.1%, negative predictive value of 93.2%, and an overall diagnostic accuracy of 71.3%. ROC analysis showed an area under the curve (AUC) of 0.86 (95% CI: 0.80–0.92). Conclusion: MRI with O-RADS scoring provided high sensitivity and reliability in excluding malignancy among sonographically indeterminate adnexal masses. Its application improved diagnostic confidence, minimized unnecessary surgical procedures, and guided more accurate clinical decision-making, making it a valuable adjunct to ultrasound in routine practice.