•The LR-5 CEUS class is an optimal diagnostic tool for HCC.
•The other LR classes (LR-3, LR-4 and LR-M) require histological confirmation.
•These data could change the diagnostic algorithm of HCC.
Background & Aims
The use of contrast enhanced ultrasound (CEUS) for the diagnosis of hepatocellular carcinoma (HCC) in cirrhosis was questioned for the risk of false positive diagnosis in case of cholangiocarcinoma. The American College of Radiology has recently released a scheme (CEUS LI-RADS) classifying lesions at risk for HCC investigated by CEUS. Aim of the present study was to validate this LI-RADS scheme for the diagnosis of HCC.
A total of 1006 nodules in 848 patients with chronic liver disease at risk for HCC collected in 5 Italian centers were retrospectively analyzed. Nodules were classified as LR-5, (HCC) if ≥ 1 cm with arterial phase hyperenhancement, and late washout (onset ≥60 seconds 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 (=506) or histology (n=500).
Median size was 2 cm. Of 1006 nodules, HCC were 820 (81%), cholangiocarcinoma 40 (4%), regenerative nodules (±dysplastic) 116 (11%). 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%).
The CEUS LI-RADS class LR-5 is highly specific for HCC, enabling its use for a confident non invasive diagnosis.