Diagnosis of 26 small hepatocellular carcinoma using incremental dynamic computed tomography.

Hepatocellular carcinoma (HCC) is usually visualized as high density area in early phase of an incremental dynamic computed tomography (ID-CT). Small HCC nodules less than 2 cm in diameter are sometimes, however, showing no contrast enhancement. We examined 26 HCC nodules less than 2 cm in diameter by ID-CT. All HCC nodules examined were originally detected by ultrasonography and diagnosed by fine needle biopsy in histology. We studied the sensitivity of ID-CT in detecting HCC nodules and a possible association between a presence or absence of contrast enhancement and the degree of cell differentiation of HCC nodules. Of the 26 HCC nodules, 22 (84.6%) were detected by ID-CT. Of the 22 detected nodules, 7 were depicted as high density area in early phase of ID-CT, and 5 were moderately differentiated HCC and the other 2 were poorly differentiated HCC in histology. Twelve nodules were low density area in early phase of ID-CT, and all of them were well-differentiated HCC. The other 3 nodules, which were isodense in early phase, were depicted as low density area in late phase, and 2 were well-differentiated HCC and other was moderately differentiated HCC. In this study, most of small and well-differentiated HCC nodules less than 2 cm in diameter showed no contrast enhancement in early phase of ID-CT. Therefore, when ID-CT of intrahepatic nodules less than 2 cm shows low density in early phase without contrast enhancement, well-differentiated HCC are most suspected, and further examinations such as magnetic resonance imaging and needle biopsy are needed.