HEPATIC AND PORTAL SURFACE VEINS - A NEW ANATOMIC VARIANT REVEALED DURING ABDOMINAL CT

OBJECTIVE. The objective of this paper is to describe a new finding on CT of hepatic and portal vein segments located in a subcapsular locat ion on the surface of the liver. SUBJECTS AND METHODS. From a series o f more than 11,000 contrast-enhanced abdominal CT scans performed from 1993 to 1997, 14 patients were identified as having hepatic or portal vein segments or both in a subcapsular location on the surface of the liver. RESULTS. We found seven portal vein surface segments in seven patients and 14 hepatic vein surface segments in 12 patients. Of the 1 4 patients, five had both portal and hepatic vein surface segments. Th erefore, in a cohort that exceeded 11,000 patients, the incidence of t his finding was 0.1%, Four patients had cirrhosis, two had small hyper vascular liver lesions, and eight had healthy livers. The surface vein s were not associated with any other recognized vascular anomalies or with anastomoses to extrahepatic systemic veins. CONCLUSION. Hepatic a nd portal veins can course to a subcapsular location on the surface of the liver. This anatomy is believed to be a normal variant and can be found in patients with healthy livers and normal hepatic vein hemodyn amics and in patients with portal hypertension.