title: Hepatic and portal surface veins: a new anatomic variant revealed during abdominal CT.
abstract: OBJECTIVE
  The objective of this paper is to describe a new finding on CT of hepatic and portal vein segments located in a subcapsular location on the surface of the liver.
  
  
  METHODS
  From a series of 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 14 patients, five had both portal and hepatic vein surface segments. Therefore, in a cohort that exceeded 11,000 patients, the incidence of this finding was 0.1%. Four patients had cirrhosis, two had small hypervascular liver lesions, and eight had healthy livers. The surface veins were not associated with any other recognized vascular anomalies or with anastomoses to extrahepatic systemic veins.
  
  
  CONCLUSIONS
  Hepatic and 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 hemodynamics and in patients with portal hypertension.
authors.affiliation: Department of Radiology, University of Washington School of Medicine, Seattle 98195, USA.
authors.forename: L
authors.initials: L
authors.lastname: Sheporaitis
authors.forename: P C
authors.initials: PC
authors.lastname: Freeny
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006503:Hepatic Veins / Q000000981:diagnostic imaging*; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011860:Radiography, Abdominal; D014057:Tomography, X-Ray Computed