Contrast ultrasound LI-RADS LR-5 identifies hepatocellular carcinoma in cirrhosis in a multicenter restropective study of 1,006 nodules

Background & Aims: The use of contrast enhanced ultrasound (CEUS) for the diagnosis of hepatocellular carcinoma (HCC) in cirrhosis was questioned because of the risk of a false positive diagnosis in cases of cholangiocarcinoma. The American College of Radiology has recently released a scheme (CEUS Liver Imaging Reporting and Data System [LI-RADS (R)]) to classify lesions at risk of HCC investigated by CEUS. The aim of the present study was to validate this LI-RADS scheme for the diagnosis of HCC.Methods: A total of 1,006 nodules from 848 patients with chronic liver disease at risk of HCC were collected in five Italian centers and retrospectively analyzed. Nodules were classified as LR-5, (HCC) if >= 1 cm with arterial phase hyperenhancement, and late washout (onset >= 60 s after contrast injection) of mild degree. Rim enhancement and/or early and/or marked washout qualified lesions as LR-M (malignant, but not specific for HCC). Other combinations qualified lesions at intermediate risk for HCC (LR-3) or probable HCC (LR-4). Diagnostic reference standard was CT/MRI diagnosis of HCC (n = 506) or histology (n = 500).Results: The median nodule size was 2 cm. Of 1,006 nodules, 820 (81%) were HCC, 40 (4%) were cholangiocarcinoma, 116 (11%) regenerative nodules (+/- dysplastic). The LR-5 category (52% of all nodules) was 98.5% predictive of HCC, with no risk of misdiagnosis for pure cholangiocarcinoma. Sensitivity for HCC was 62%. All LR-M nodules were malignant and the majority of non-hepatocellular origin. Over 75% of cholangiocarcinomas were LR-M. The LR-3 category included 203 lesions (HCC 96 [47%]) and the LR-4 202 (HCC 173 [87%]).Conclusions: The CEUS LI-RADS class LR-5 is highly specific for HCC, enabling its use for a confident non-invasive diagnosis. (C) 2017 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.