Contrast-enhanced ultrasound of hepatocellular carcinoma: correlation between enhancement pattern and cellular differentiation on histopathlogy.

The aim of this study was to evaluate and correlate the enhancement pattern of hepatocellular carcinoma (HCC) on contrast-enhanced ultrasound (CEUS) and tumour cellular differentiation on histopathology. Patients underwent hepatic CEUS, performed with SonoVue and contrast pulse sequencing. The correlation between enhancement time and enhancement level of the lesions in different vascular phases and tumour cellular differentiation was determined. The tumours were graded according to the Edmondson grading system. Then, diagnosis was obtained by histopathological examination following surgery or percutaneous ultrasound-guided biopsy. 189 patients with HCC were examined with CEUS and histopathological examination between 2003 and 2009: 159 had a solitary lesion (85 %), 24 had 2 lesions (12 %) and 6 had multiple lesions (3 %). The final histological grading of the tumours was as follows: 22, 114, 49, 4 grade I-IV, respectively. Significant differences were shown between the time that HCC become hypoenhancing or remained echogenic in late phase and tumour cellular differentiation (p = 0.006, p = 0.036). The timing of HCC becoming hypoenhancing was correlated with tumour cellular differentiation, with better differentiated HCCs washing out more slowly than poorly differentiated ones (p = 0.164, p = 0.113; p = 0.186, p = 0.070). The enhancement pattern of HCC by CEUS correlates with the cellular differentiation. In late phases, hyperechoic lesions are likely to be better differentiated, whereas hypoechoic lesion is more likely to be poorly differentiated.