Risk stratification for hepatocellular carcinoma of contrast-enhanced ultrasound Liver Imaging Reporting and Data System (LI-RADS) and the diagnostic performance of LR-5 and LR-M: a systematic review and meta-analysis

To evaluate the risk stratification of hepatocellular carcinoma (HCC) and overall malignancies in different contrast-enhanced ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) categories, and to explore the diagnostic performance of LR-5 for HCC and LR-M for non-HCC malignancies. The PubMed, Embase, and Cochrane Central databases were searched from 2016 to February 2021 for studies on CEUS LI-RADS v2016 and v2017. The proportion of HCC and overall malignancy in each LI-RADS category and the sensitivity, specificity, accuracy, diagnostic odds ratio (DOR) and area under the receiver operating characteristic curve (AUC) of LR-5 and LR-M categories were determined using a random effects model. A total of 113 studies were retrieved and 10 studies were included. A total of 5,543 patients with 6,124 lesions were included, including 4,492 HCC. There was no HCC in LR-1, and the proportion of HCC in LR-2–5 increased with the increase of category. The proportion of HCC in LR-5 was 97%, and that in LR-M was 44%. The sensitivity, specificity, and accuracy of CEUS LR-5 for HCC were 0.76, 0.95, and 0.82, respectively, and the area under the SROC curve was 0.83. The sensitivity, specificity, and accuracy of CEUS LR-M for non-HCC malignancies were 0.81, 0.92, and 0.91, and the area under the SROC curve was 0.89. The risk of HCC increases gradually from LR-1 to LR-5, in which there was no HCC lesion in LR-1 and the proportion of HCC in LR-3 was 22%, lower than that reported in earlier studies. The proportion of HCC in LR-5 was 97% and that in LR-M was 44%. LR-5 has a high specificity of 95% for the diagnosis of HCC. •The risk of HCC increases gradually from LR-1 to LR-5.•The proportion of HCC in LR-3 was lower than that reported in earlier studies.•LR-5 had a very low misdiagnosis rate for HCC.