Diagnostic performance of the O-RADS MRI system for magnetic resonance imaging in discriminating benign and malignant adnexal lesions: a systematic review, meta-analysis, and meta-regression

Abstract

Purpose: After the introduction of the Ovarian-Adnexal Reporting and Data System (O-RADS) for magnetic resonance imaging (MRI), several studies with diverse characteristics have been published to assess its diagnostic performance. This systematic review and meta-analysis aimed to assess the diagnostic performance of O-RADS MRI scoring for adnexal masses, accounting for the risk of selection bias.

Methods: The PubMed, Scopus, Web of Science, and Cochrane databases were searched for eligible studies. Borderline or malignant lesions were considered malignant. All O-RADS MRI scores ≥4 were considered positive. The quality of the studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. The pooled sensitivity, specificity, and likelihood ratio (LR) values were calculated, considering the risk of selection bias.

Results: Fifteen eligible studies were found, and five of them had a high risk of selection bias. Between-study heterogeneity was low-to-moderate for sensitivity but substantial for specificity (I2 values were 35.5% and 64.7%, respectively). The pooled sensitivity was significantly lower in the studies with a low risk of bias compared with those with a high risk of bias (93.0% and 97.5%, respectively; P = 0.043), whereas the pooled specificity was not different (90.4% for the overall population). The negative and positive LRs were 0.08 [95% confidence interval (CI) 0.05–0.11] and 10.0 (95% CI 7.7–12.9), respectively, for the studies with low risk of bias and 0.03 (95% CI 0.01–0.10) and 10.3 (95% CI 3.8–28.3), respectively, for those with high risk of bias.

Conclusion: The overall diagnostic performance of the O-RADS system is very high, particularly for ruling out borderline/malignant lesions, but with a moderate ruling-in potential. Studies with a high risk of selection bias lead to an overestimation of sensitivity.

Clinical significance: The O-RADS system demonstrates considerable diagnostic performance, particularly in ruling out borderline or malignant lesions, and should routinely be used in practice. The high between-study heterogeneity observed for specificity suggests the need for improvement in the consistent characterization of the benign lesions to reduce false positive rates.

Keywords: Adnexal mass; ovarian cancer; Ovarian-Adnexal Reporting and Data System; agnetic resonance imaging; meta-analysis; systematic review.

Figure 1

Preferred Reporting Items for Systematic Reviews and Meta-analyses flowchart for selection of eligible studies. O-RADS, Ovarian-Adnexal Reporting and Data System; MR, magnetic resonance.

Figure 2

Methodological quality assessment according to the Quality Assessment of Diagnostic Accuracy Studies-2 tool.

Figure 3

Forest plot of the pooled sensitivity and specificity. *Online publication in 2023, ahead of print.

Figure 4

Summary receiver operating characteristics curve for the diagnostic performance of the Ovarian-Adnexal Reporting and Data System scoring. The blue circles represent individual studies, with their sizes proportional to the respective sample sizes. The red and green diamonds denote the point estimates (summary points), while the red and green solid lines illustrate the summary curves for studies with high and low risk of bias, respectively. For a more detailed depiction, including the confidence interval and prediction interval, please refer to Supplementary Figure 1.

Figure 5

Likelihood matrix shows the pooled estimate (the diamond) and 95% confidence intervals of the negative and positive likelihood ratios, and exclusion and/or confirmation potential of the Ovarian-Adnexal Reporting and Data System scoring for borderline or malignant lesions.

Figure 6

Fagan’s nomogram for the Ovarian-Adnexal Reporting and Data System (O-RADS) scoring. The green diamond on the pre-test probability line (on the left side) represents the overall pre-test probability (25%) obtained from this meta-analysis. Utilizing the pooled likelihood ratio values, the solid red arrow and the dashed grey arrow indicate the post-test probability of having a borderline or malignant lesion when the test is positive (O-RADS 4 or 5) or negative (O-RADS <4), respectively. LR, likelihood ratio.

Figure 7

Deeks’ plot for publication bias.