Depiction of vasculature in small hepatocellular carcinoma, and dysplastic nodules evaluated with carbon dioxide ultrasonography and angiography.

<bold>Purpose: </bold>To evaluate the vascularity in dysplastic nodules and well-differentiated and moderately to poorly differentiated hepatocellular carcinomas (HCCs) less than 2 cm using carbon-dioxide (CO2) US and angiography.<bold>Material and Methods: </bold>A total of 115 pathologically proven small liver tumors (0.7 approximately 2.0 cm) were included in the study. There were 31 dysplastic nodules, 49 well-differentiated HCCs and 35 moderately to poorly differentiated HCCs. A comparative study of angiography and CO2 US was carried out.<bold>Results: </bold>Of the dysplastic nodules, 28 out of 31 tumors were hypo- or isovascular at CO2 US. Twenty-seven out of 31 tumors were hypovascular at angiography. Of the well-differentiated HCCs, 38/49 showed hypervascularity at CO2 US while 24/49 tumors were hypervascular at angiography. All moderately to poorly differentiated HCCs showed hypervascularity at CO2 US, compared to 30/35 tumors at angiography.<bold>Conclusion: </bold>Most of the dysplastic nodules were hypovascular and most of the moderately to poorly differentiated HCCs were hypervascular. The vascularity of well-differentiated HCCs was in between the above tumors. Both CO2 US and angiography were equally effective in demonstrating the vascularities in dysplastic nodules and moderately to poorly differentiated HCCs. CO2 US was significantly superior to angiography when identifying the vascularity in well-differentiated HCCs. [ABSTRACT FROM AUTHOR]