Cavernous transformation of the portal vein (CTPV) is the development of venous channels around a thrombosed portal vein to serve as portoportal collaterals. There are two accepted theories explaining the pathogenesis of CTPV: 1. congenital agenesis of the portal vein leads to periportal collateralization and 2. that it is a portal vein hemangioma.
The main causes of portal vein thrombosis in adults are hepatocellular carcinoma, pancreatitis, cirrhosis, liver transplantation, and splenectomy. CTPV may occur in as little as 6-20 days after the insult to the portal vein.
CECT will characteristically show a mass of veins with a beaded appearance at the porta hepatis. Intrahepatic extension of the cavernous transformation can occur. Hepatic arterial phase imaging will demonstrate heterogeneous, patchy areas of high attenuation along the liver periphery (collateral channels better supply the central regions of the liver causing increased peripheral arterial inflow).
Doppler ultrasound shows hepatopetal flow in the cavernoma lacking the respiratory undulation of a normal portal vein.
The images above are from a patient with a patent main portal vein but thrombosis of the left and segments of the right portal veins, with CTPV formation.
De Gaetano AM, Lafortune M, Patriquin H, et al. Cavernous transformation of the portal vein: patterns of intrahepatic and splanchnic collateral circulation detected with Doppler sonography. AJR Am J Roentgenol 1995; 165:1151–1155.
Gallego C, Velasco M, Marcuello P, et al. Congenital and acquired anomalies of the portal venous system. Radiographics. 2002 Jan-Feb;22:141-159.