Delayed enhancement of hepatocellular carcinoma on dynamic CT: sign of extrahepatic collaterals after transcatheter arterial chemoembolization or transcatheter arterial chemoinfusion

Background: We examined the factors of delayed enhancement of hepatocellular carcinoma (HCC) on dynamic computed tomography (CT). Methods: Dynamic CT and angiography were compared in 113 patients who had undergone transcatheter arterial chemoembolization or transcatheter arterial chemoinfusion and were suspected of developing new HCCs. Results: Eight of 113 patients had HCC nodules that enhanced gradually from the arterial phase to the portal venous phase on dynamic CT and were fed by extrahepatic arteries on angiography. The feeding artery was an omental branch of the splenic artery in one lesion, an omental branch of the gastroduodenal artery in five, and the intercostal artery in two. Conclusion: We believe that the recurrence of HCCs delayed enhancement on dynamic CT because the hepatic artery was hidden and long narrow extrahepatic collaterals fed the tumor.