POSTERIOR ASPECT OF HEPATIC SEGMENT-IV - PATTERNS OF PORTAL VENULE BRANCHING AT HELICAL CT DURING ARTERIAL PORTOGRAPHY

PURPOSE: To determine the anatomy of the portal venous system in the p osterior aspect of segment IV of the liver by using helical computed t omography (CT) during arterial portography (CTAP). MATERIALS AND METHO DS: One hundred consecutive patients underwent CTAP. Helical CT during hepatic arteriography was performed in 20 patients. In seven patients with hepatocellular carcinoma in the posterior aspect of segment IV, the feeding arteries were also analyzed. RESULTS: A venule from the in trahepatic portal vein to segment IV was seen in all patients. Other f indings included a tiny venule from the distal part of the main left p ortal vein (n = 36), from the proximal left main portal vein (n = 20), and from the right portal vein (n = 18). Aberrant right gastric venou s drainage and/or parabiliary venous drainage directly into the poster ior aspect was present in 14 patients. In two patients, a tiny accompa nying artery was seen on images from CT during hepatic arteriography. In seven patients with hepatocellular carcinoma, the main feeding arte ry branched from the right (n = 2) or left (n = 5) hepatic artery. CON CLUSION: CTAP adequately demonstrates the tiny portal venous and arter ial branches from the main right or left portal vein that distribute t o the posterior aspect of segment IV. Knowledge of this vascular anato my is clinically important.