Contrast-Enhanced Ultrasound for the Characterization of Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma

PURPOSE AND METHODS: The ability of contrast-enhanced ultrasound (CEUS) to differentiate between hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) is still controversial. We reviewed the CEUS imaging of 819 patients (HCC=546, ICC=273) with an established pathological diagnosis. The enhancement patterns of lesions and the diagnostic performance of CEUS were analyzed. RESULTS: Arterial hyperenhancement followed by washout was observed in 92.3% (504/546) of the HCC lesions and 85.7% (234/273) of the ICC lesions on CEUS (p<0.05). Additionally, the ICCs presented contrast washout much earlier than the HCCs, with an average time of 27.5 seconds after injecting the contrast agent compared with 70.1 seconds for the HCCs (p<0.05). Peripheral rim-like enhancement was observed in 68.5% (187/273) of the ICCs, which was significantly more common than that in the HCCs (2.0%, 11/546) (p<0.05). When using arterial hyperenhancement with a washout phase later than 43 seconds after injecting the contrast agent and with no peripheral rim-like enhancement as the diagnostic criteria for HCC ≤5 cm in diameter, the area under the curve was 0.808, with 64.1% sensitivity, 97.4% specificity and 73.6% accuracy. CONCLUSIONS: Although ICC may show the typical enhancement pattern of HCC on CEUS, peripheral rim-like enhancement and quick contrast washout show high efficiency in the differentiation of HCC from ICC.