Demonstration of growing casts of hepatocellular carcinoma in the portal vein by celiac angiography: The thread and streaks sign.

In 9 of 112 patients with hepatocellular carcinoma (HCC) examined by selective celiac and hepatic arteriography, an unusual finding, the "thread and streaks" sign, was observed. It began to appear shortly after the start of injection and was most clearly seen at 3.0-3.5 seconds. Histopathologic and radiographic studies of excised livers have demonstrated that these thin streaks correspond to the blood spaces and vessels which run longitudinally in and around a tumor cast growing in a large branch and trunk of the portal vein.