Non-tumorous enhancement caused by cholecystic venous inflow shown on biphasic CT hepatic arteriography: comparison with hepatocellular carcinoma

The haemodynamics in non-tumorous abnormalities on CT arterial portography (CTAP) owing to cholecystic venous direct inflow to the liver were compared with the haemodynamics in hepatocellular carcinoma. 53 patients who simult aneously underwent CTAP and CT during hepatic arteriography (CTHA) to detec t hepatocellular carcinoma had the late phase added to CTHA. Changes in siz e, shape and pattern of 47 non-tumorous enhancement abnormalities on the li ver around the gall bladder or in the dorsum of segment IV between the earl y and late phases on biphasic CTHA as well as of 60 tumorous lesions were d etermined. Enhancement on biphasic CTHA was seen in all 47 lesions with a n on-tumorous portal defect (early phase alone, n=8; late phase alone, n=3; b oth, n=36). In these 47 lesions, the size and the shape of enhancement chan ged in 63.8% and 51.1%, respectively, between the early and late phases on CTHA; the pattern of enhancement did not change in 72.3%. On the other hand , the size of enhancement on biphasic CTHA changed in only 16.7% of 60 tumo urs, and the shape in only 5%, although the enhancement pattern changed in a large proportion (80%). In conclusion, owing to the difference in haemody namics, non-tumorous abnormalities caused by cholecystic venous inflow and tumours are clearly delineated on biphasic CTHA. Thus, adding the late phas e to previous single phase CTHA (i.e. performing biphasic CTHA) is useful i n differentiating the two entities.