Portal vein variations on routine contrast enhanced computed tomography of abdomen and its association with prevalence of accessory inferior right hepatic vein

Abstract Purpose To determine the prevalence of portal vein variations in patients undergoing routine contrast-enhanced computed tomography (CECT) of the abdomen. Secondary objective was to determine any association between variant portal venous anatomy and prevalence of accessory inferior right hepatic vein (IRHV). Materials and methods A retrospective review of 500 patients was performed who underwent routine CECT abdomen over a period of six months. A total of 406 patients were included in the study (N = 406). Thin axial, multiplanar reformatted and maximum intensity projection computed tomography (CT) images were used to determine variant portal venous anatomy. In a subset of 381 patients with adequate opacification of hepatic veins, presence of an accessory IRHV was also noted. Results Normal type I portal venous anatomy was present in 314 out of 406 patients (77.34%). Variant portal venous anatomy was encountered in 22.66% cases. Type III portal vein (right posterior portal vein as first branch of main portal vein) was the most common variant seen in 9.61% of cases. Type II portal vein (trifurcation of main portal vein) was seen in 7.14% cases. There was no statistically significant difference between prevalence of IRHV in patients with normal and variant portal venous anatomy (p value = 0.145) Conclusion It is not uncommon to encounter portal venous variations on routine CECT abdomen. Type III portal vein was most commonly encountered variant in our study. Recognition of variant portal venous anatomy is important for surgeons and interventional radiologists.