Portal vein variations: clinical implications and frequencies in routine abdominal multidetector CT.

PURPOSE The aim of this study was to determine the types, prevalence rates, and clinical implications of portal vein (PV) variations using routine abdominal multidetector computed tomography (MDCT). MATERIALS AND METHODS The study included 1384 retrospectively evaluated patients (721 males, 663 females) that had undergone routine abdominal MDCT. Portal phase CT scans (2.5 mm collimation, table speed/rotation time, 12.5 mm/0.5 s) were acquired 60 s after contrast material injection. Two radiologists interpreted the images and reached a consensus on all findings. Types and frequencies of PV variations were noted. RESULTS Normal PV branching patterns were observed in 1005 (72.6%) of the patients. PV variants and anomalies were identified in 379 patients (27.4%). Normal main PV branching patterns were noted in 1087 (78.5%) of the patients. Main PV branching variations were seen in 297 (21.5%) of the patients. The most frequent types of these variations were trifurcation (n = 154, 11.1%) and right posterior PV as the first branch of the main PV (n = 134, 9.7%). Right PV variation was identified in 42 (3.9%) of the 1087 patients with type 1 anatomy. Variation of the origin of the segmental PV that traversed the interlobar boundary was identified in 55 (4%) of the 1384 patients. CONCLUSION The prevalence of PV variations was high in patients that underwent abdominal CT, and routine abdominal MDCT demonstrated these abnormalities very well. Clinically relevant PV variants should be reported in routine CT evaluations.