Intrahepatic Portal Venous Variations: Demonstration by Helical CT During Arterial Portography

Abstract

We assessed the prevalence and types of intrahepatic portal venous variations by helical computed tomography performed with arterial portography (CTAP). In 192 patients without evidence of vascular invasion or distortion, CTAP images were reviewed retrospectively to identify portal venous variations. Of the 192 patients examined, 10 (5.2%) had trifurcation, 5 (2.6%) had a right posterior segmental branch arising from the main portal vein, 5 (2.6%) had an absence of the horizontal segment of the left portal vein, and 1 (0.5%) had an absence of the left lateral segmental portal branch. Of the patients without a horizontal segment, two had a right-sided ligamentum teres associated with malposition of the gallbladder, while another had complete ramification of intrahepatic portal branches from an umbilical vein-like segment. In the patient missing the left lateral segmental branches, the right portal vein segments were subcapsularly located. Variations of the intrahepatic portal veins can be recognized on CTAP imaging. tomography-Portal vein, computed tomography.