Radiological detectability of minute hepatic venous invasion in hepatocellular carcinoma

Objective: To determine if minute hepatic venous invasion in hepatocellular carcinoma (HCC) can be diagnosed radiologically. Materials and methods: CT hepatic arteriography (CTHA) and CT arterioportography (CTAP) of 95 cases with HCCs were examined. Histopathology after surgery has been the gold standard in all patients. Based on the presence of microscopic portal venous invasion (MPVI) and microscopic hepatic venous invasion (MHVI), the cases were classified into four groups as follows: Group vp0vv0, negative MPVI and MHVI; Group vp1vv0, positive MPVI and negative MHVI; Group vp0vv1, negative MPVI and positive MHVI; Group vp1vv1, positive MPVI and MHVI. An area showing low attenuation on CTAP and high attenuation on CTHA around the tumor was defined as an area of peritumoral hemodynamic change (APTHC). The shape and size of APTHC were compared between Groups vp0vv1 and vp0vv0 or between Groups vp1vv1 and vp1vv0. The ratio of APTHC volume to tumor volume (RAT) was employed as an indicator of APTHC size. Each comparison was also made independently when tumor diameter was limited to either less than 3 cm or 3 cm or more. Results: Three types of APTHC were identified: wedge-shaped, belt-shaped or irregular, and linear. No significant difference in the frequency of each type of APTHC was observed between Groups vp0vv1 and vp0vv0 or between Groups vp1vv1 and vp1vv0. There was no significant difference in RAT between Groups vp0vv1 and vp0vv0 or between Groups vp1vv1 and vp1vv0, unrelated to tumor size. Conclusions: The presence of minute hepatic venous invasion in HCC is difficult to determine even on combined CTHA and CTAP.