Objectives: To evaluate the association of BI-RADS 5th edition distribution and type of enhancement descriptors with the malignancy of non-mass enhancement (NME) lesions.

Methods: Medline via PubMed, Scopus, Web of Science, ProQuest, and Embase databases were systematically searched from January 2013 to July 2022 for original studies, written in English, reporting the positive predictive value (PPV) of individual BI-RADS 5th edition descriptors (distribution and type of enhancement) of NME lesions. Risk of bias and quality of included studies were assessed by QUADAS 2 appraisal tool. Odds ratio (OR) of pathologically confirmed malignant results in each distribution and internal enhancement were pooled in a meta-analysis.

Results: Eight studies for a total of 1095 lesions were included. The pooled OR of malignancy for linear, focal, segmental, regional, multiple region, and diffuse distributions are 0.70 (95%CI: 0.44-1.14), 0.37 (95% CI: 0.26-0.54), 2.42 (95% CI: 1.62-3.62), 0.56 (95% CI: 0.11-2.79), 2.80 (95% CI: 0.96-8.21), and 3.35 (95% CI: 0.59-19.04), respectively. The pooled OR of malignancy for homogenous, heterogeneous, clustered ring enhancement, and clumped enhancement are 0.39 (95% CI: 0.23-0.67), 0.59 (95% CI: 0.40-0.85), 2.92 (95% CI: 1.86-4.57), and 1.49 (95% CI: 0.96-2.32), respectively.

Conclusion: Based on a meta-analysis of 8 studies and more than one thousand non-mass enhancing lesions, diffuse, multiple regions and clustered ring descriptors of enhancement have the highest pooled OR for malignancy.