Possibility of differentiating small hyperechoic liver tumours using contrast-enhanced colour Doppler ultrasonography: a preliminary study.

We performed a preliminary study to investigate the possibility of differentiating small hyperechoic liver tumours, including hepatocellular carcinomas (HCCs), haemangiomas and focal fatty lesions, by administering a galactose-based contrast agent (SH/TA-508 (Levovist)) during colour Doppler ultrasonography (US). Ten patients (age range: 48-81 years) with small liver tumours (four HCCs, four hemangiomas and two focal fatty lesions) of less than 20 mm in diameter presented with hyperechoic masses with no intratumoural colour signals on conventional colour Doppler US. All patients subsequently underwent colour Doppler US with this contrast agent. Colour Doppler images of the tumours were assessed before and after the intravenous injection of 8 ml of the contrast agent at a concentration of 400 mg/ml. Prior to injection of the contrast agent, no intratumoural colour signals were observed in any cases. After injection, intratumoural colour signals appeared in all HCCs and in two haemangiomas with tumour-margin enhancement. The enhanced colour signals appeared to be related to cardiac contraction in the HCCs, but not in the haemangiomas. In the remaining two haemangiomas, only tumour-margin enhancement was observed. In the focal fatty lesions, neither intratumoural nor tumour-margin enhancement was observed. These results, although preliminary, suggest that the detection of colour Doppler signals is improved by using a contrast agent and the differences between enhanced colour signals from HCCs and haemangiomas may help differentiate hyperechoic HCCs from other hyperechoic tumours, including haemangiomas and focal fatty lesions.