US Liver Imaging Reporting and Data System Version 2017: A Systematic Review and Meta-Analysis

Abstract

Background The US Liver Imaging Reporting and Data System (LI-RADS) includes an assessment category (US-1, negative; US-2, subthreshold; and US-3, positive) and a visualization score reflecting image quality (VIS-A, no or minimal limitations; VIS-B, moderate limitations; and VIS-C, severe limitations). The US-3 and VIS-C impact patient treatment. Purpose To establish the distributions of categories and visualization scores, estimate the proportions of hepatocellular carcinoma (HCC) and overall malignancy in the US-3 category, and identify variables associated with the VIS-C score by conducting a meta-analysis. Materials and Methods A systematic search of articles published between January 1, 2017, and September 17, 2023, identified studies reporting distributions of US LI-RADS version 2017 categories or visualization scores. Characteristics of the study design, patient cohorts, and outcomes of interest (distributions of US categories and visualization scores, percentages of probable or definite HCC and malignancy in US-3 category, and variables associated with VIS-C) were extracted. For the meta-analysis, estimates were established with random-effects models. Results Fifteen studies comprising 39 166 US examinations were included. Of all examinations, 89.7% (95% CI: 86.8, 91.8) were categorized US-1; 4.4% (95% CI: 2.8, 6.2), US-2; and 5.9% (95% CI: 4.1, 8.0), US-3. Of the US-3 examinations, 25.9% (95% CI: 17.1, 34.7) had probable or definite HCC and 26.4% (95% CI: 18.4, 34.5) had overall malignancy. Among all examinations, 59.7% (95% CI: 46.9, 67.8) were assigned VIS-A; 32.5% (95% CI: 21.9, 41.6), VIS-B; and 7.8% (95% CI: 2.8, 14.3), VIS-C. Obesity (odds ratio [OR], 2.37; 95% CI: 1.57, 3.59), nonalcoholic fatty liver disease (NAFLD) (OR, 2.24; 95% CI: 1.64, 3.06), and Child-Pugh B or C (OR, 2.41; 95% CI: 1.43, 4.06) were associated with VIS-C score. Conclusion Overall, 90% of surveillance US results were negative (US-1), and 92% were of adequate quality (VIS-A or VIS-B); 26% of patients with US-3 results had HCC. VIS-C was associated with obesity, NAFLD, and cirrhosis. Systemic review registry no. CRD42022384925