Hepatic Artery and Portal Vein Variations using Contrast Enhanced Computed Tomography Abdominal Angiography

Introduction: Normal hepatic vascular anatomy and its variants carry considerable importance during liver transplants, laparoscopic surgeries, penetrating abdominal trauma, and radiological abdominal interventions. The occurrence of iatrogenic hepatic vascular injury increases in case of atypical anatomy and variations. Aim: To determine the prevalence of common hepatic artery and portal vein variants by using Multidetector Computed Tomography (MDCT). Materials and Methods: This is a hospital based retrospective study done in Sri Mankula Vinayagar Medical College and Hospital, Puducherry, India, between July 2019 and July 2020. The Contrast Enhanced Computed Tomography (CECT) abdominal angiography of 350 patients was taken for the study. The MDCT abdominal angiography was performed using 16 slice PHILIPS MX16 CT scanner with intravenous administration of non ionic iodinated contrast, having iodine content of 300 mg/mL at the dosage of 1.5 mL/kg body weight, using automated pressure injector at a rate of 3.5 mL/sec. Arterial phase and portal venous phase images were obtained at 25 and 55 seconds respectively. The hepatic artery anatomical types were classified according to Michel's classification and the portal vein according to Covey AM et al., classification. Data obtained was entered in EPI INFO version 7.2.1.0 and analysed using Statistical Package for the Social Sciences (SPSS) software version 24.0. Results: Hepatic artery proper (right and left hepatic arteries arising from common hepatic artery) (Type I) was seen in 222 (63.4%) of cases. The most common variant was replaced Left Hepatic Artery (LHA) from the left gastric artery (Type II) with a prevalence of 46 (13.1%). A normal portal vein branching pattern (Type I) was seen in 201 (57.4%) of cases. The most common variation was trifurcation (Type II) with a prevalence of 68 (19.4%). Conclusion: Knowledge about normal hepatic artery, portal vein, and its variants is important in hepatic interventions and CT angiography is the modality of choice for evaluating the vascular anatomy.