Diagnosis and follow-up of small hepatocellular carcinoma with selective intraarterial digital subtraction angiography.

To clarify the angiographic features of small hepatocellular carcinoma, we performed digital subtraction angiography in 91 patients with hepatocellular carcinomas of 2 cm or less. Repeated digital subtraction angiography studies were performed in 25 patients whose first angiograms showed no tumor staining. Digital subtraction angiography showed hypervascular tumor staining in only 51 patients (56.0%). We found that the smaller a tumor nodule was, the lower the detection rate of tumor stain on digital subtraction angiography. The detection rate of hypervascularity was closely correlated with the grading of histological differentiation of the tumors: well-differentiated hepatocellular carcinomas more often showed negative tumor staining. Repeated digital subtraction angiography studies showed alteration of tumor staining from isovascular to hypervascular in 6 of 6 patients with tumors that became larger than 2 cm and in 12 of 19 patients with tumors that remained 2 cm or smaller. Conversion of vascularity is commonly found in the early stage of small hepatocellular carcinoma, and the process is usually slow, taking approximately 1 yr.