Diagnostic Performance of O-RADS MRI Scoring System for the Assessment of Adnexal Masses in Routine Clinical Radiology Practice- A Single Tertiary Centre Prospective Cohort Study

Abstract

Introduction: In 2019-20, the American College of Radiology (ACR) introduced Ovarian-Adnexal Reporting and Data System Magnetic Resonance Imaging (O-RADS MRII). Application of the O-RADS MRI in routine clinical practice can increase lesion characterization accuracy, promote better interdisciplinary communication, and help in personalized patient management of adnexal masses. Aim: To assess the diagnostic performance of the ACR O-RADS MRI scoring system for the predicting malignancy in adnexal mass in routine clinical radiology practice by using histology/ imaging findings during a minimum 4 month follow-up as the reference standard. Materials and Methods: In this single- tertiary center prospective cohort study done in Jorhat Medical College, Assam, 42 patients with 46 adnexal masses who underwent MRI between April 2020 and June 2021 were assessed. The ACR O-RADS MR scores were assigned using the MRI protocol with a dynamic study. Sensitivity, specificity, positive and negative predictive values along with the area under the Receiver Operating Characteristic (ROC) curve were calculated (cut-off score ≥4 was considered malignancy,). Histopathologic diagnosis or >4 months followup imaging findings was the reference standard used. Logistic regression analysis of MRI parameters used in identifying malignant masses was assessed. Statistical analysis was done using 95% confidence intervals (CIs). The p-values <0.05 was considered statistically significant. Results: The mean age of subjects in the study was 35.9 (range 10-75 years), and 84.8% of adnexal masses (39) were premenopausal. Malignancy was more common in postmenopausal patients (57.1%). Of 46 lesions, 13 (33.3%) were malignant. The ACR O-RADS-MR scoring system, using a dynamic MRI protocol, showed 92.3% sensitivity and 87.8%specificity in malignancy prediction. The area under the ROC curve for predicting malignancy was 0.962. The positive and negative predictive values were 75% and 89.1%, respectively. Conclusion: In a teaching hospital in assam, the O-RADS MRI scoring system, based on a dynamic MRI protocol demonstrated good sensitivity, specificity and area under the Receiver Operator Characteristic (ROC) curve in identifying malignant adnexal masses. The ACR O-RADS MRI system enables standardized MRI reporting with uniform lexicon and interpretation guide on adnexal masses.This will help to improve communication between radiologists and referring physician and in patient management, particularly in indeterminate masses on ultrasound.