Contrast-Enhanced Sonography for the Characterisation of Hepatocellular Carcinomas - Correlation with Histological Differentiation

Abstract

We aimed to characterise the vascularisation patterns of hepatocellular carcinomas in contrast-enhanced sonography in correlation to the histological differentiation of hepatocellular carcinomas (HCC), and we also compared the diagnostic value of contrast-enhanced sonography in addition to B-scan sonography and power Doppler sonography. 51 hepatocellular carcinomas (21 well differentiated, 27 moderately differentiated, 3 poorly differentiated) were examined: by B-scan sonography, power Doppler sonography and contrast-enhanced sonography using phase or pulse inversion harmonic imaging with a low mechanical index (< 0.3) and second generation microbubble contrast medium (Optison, Sonovue) as echo-enhancing agent. Lesion vascularity and the kinetics of contrast enhancement within the lesions in the early arterial phase, arterial phase, portal phase and late phase were analysed. The final diagnosis of a HCC was assessed after B-scan sonography, power Doppler sonography and contrast-enhanced sonography. Hypervascularisation and/or irregular tumour vascularisation could be detected in 18/48 HCCs (37.5%) by power Doppler sonography. After contrast application, 46/51 HCCs (90.2%) were identified as hyperechoic lesions during the early arterial or arterial phase with no correlation to histological differentiation. In the portal phase and late phase, the echogenicity of HCCs after contrast application was variable. A hypoechoic appearance was noted in 17/51 HCCs (33.3%) in the portal phase and in 21/51 HCCs (41.2%) in the late phase. Moderately differentiated HCCs were more often hypoechoic than well differentiated HCCs (p = 0.04). Contrast-enhanced sonography is highly efficient for the detection of tumour vascularity in HCCs. The majority of HCCs--regardless of histological differentiation--can be characterised as hypervascular lesions in the early arterial and arterial phase with irregular tumour vessels using contrast-enhanced sonography. In addition to B-scan sonomorphology, contrast-enhanced sonography may offer helpful information in patients with liver cirrhosis and focal liver lesions.