Systematic Review and Meta-Analysis of O-RADS Ultrasound and O-RADS MRI for Risk Assessment of Ovarian and Adnexal Lesions

BACKGROUND. O-RADS ultrasound (US) and O-RADS MRI have been developed to standardize risk stratification of ovarian and adnexal lesions. OBJECTIVE. The purpose of this study was to perform a meta-analysis evaluating the diagnostic performance of O-RADS US and O-RADS MRI for risk stratification of ovarian and adnexal lesions. EVIDENCE ACQUISITION. We searched the Web of Science, PubMed, Cochrane Library, Embase, and Google Scholar databases from January 1, 2020, until October 31, 2022, for studies reporting on the performance of O-RADS US or O-RADS MRI in the diagnosis of malignancy of ovarian or adnexal lesions. Study quality was assessed with QUADAS-2. A hierarchic summary ROC model was used to estimate pooled sensitivity and specificity. Heterogeneity was assessed with the Q statistic. Metaregression analysis was performed to explore potential sources of heterogeneity. O-RADS US was compared with the International Ovarian Tumor Analysis (IOTA) simple rules and Assessment of Different Neoplasias in the Adnexa (ADNEX) model in studies providing head-to-head comparisons. EVIDENCE SYNTHESIS. Twenty-six studies comprising 9520 patients were included. O-RADS US was evaluated in 15 and O-RADS MRI in 12 studies; both systems were evaluated in one of the studies. Quality assessment revealed that risk of bias or concern about applicability most commonly related to patient selection. Pooled sensitivity and specificity of O-RADS US were 95% (95% CI, 91-97%) and 82% (95% CI, 76-87%) and of O-RADS MRI were 95% (95% CI, 92-97%) and 90% (95% CI, 84-94%). Analysis with the Q statistic revealed significant heterogeneity among studies of O-RADS US in both sensitivity and specificity (both p < .001) and among studies of O-RADS MRI in specificity (p < .001) but not sensitivity (p = .07). In metaregression, no factor was significantly associated with sensitivity or specificity of either system (all p > .05). O-RADS US showed no significant difference in sensitivity or specificity versus IOTA simple rules in four studies (sensitivity, 96% vs 93%; specificity, 76% vs 82%) or versus the ADNEX model in three studies (sensitivity, 96% vs 96%; specificity, 79% vs 78%). CONCLUSION. O-RADS US and O-RADS MRI both have high sensitivity for ovarian or adnexal malignancy. O-RADS MRI, but not O-RADS US, also has high specificity. CLINICAL IMPACT. Awareness of the diagnostic performance results regarding O-RADS US and O-RADS MRI will be helpful as these systems are increasingly implemented into clinical practice.