Diagonosis of main and right portal vein branching variations with CT

Objective:Our objective was to investigate the prevalence of variant main and right portal vein ramification.Methods:The study group consisted of 200 patients who underwent consecutive contrast-enhanced abdominal CT examinations performed with an 16-MDCT scanner.Two observers evaluated both thin axial sections and 3D maximum-intensity-projection and volume-rendered images for branching patterns of the main and right portal veins.Results:Conventional main portal vein anatomy was present in 64.5% of the patients.In 9.5% of the patients,the main portal vein trifurcated into the left portal and right anterior and posterior portal veins.In 23.5% of the patients,the main portal vein divided into a common left portal vein right anterior portal vein trunk and the right posterior portal vein.Three patients(1.5%) had miscellaneous variations.Twenty-two(16.8%) of 131 patients with conventional main portal vein branching had variant right portal vein branching,most of which was a trifurcation,followed by an abnormally proximal origin of the segment VII vein from the right portal vein.Conclusion:Variant main portal vein branching seems to be very frequent.Common right anterior portal vein-left portal vein trunk is far more common than trifurcation.Although less frequent,variations also occur in right portal vein branching.