Portal Vein Variations Research Articles

Portal vein variations in 1000 patients: surgical and radiological importance.

The purpose of the study was to evaluate the spectrum and incidence of intrahepatic portal vein (PV) variations on triphasic abdomen multidetector CT (MDCT) and to discuss the surgical and radiological implications. A retrospective review of 1000 triphasic MDCT abdomen scans was performed in patients sent for various liver and other abdominal pathologies between January 2014 and August 2014. A total of 967 patients (N = 967) were included in the study. The variations in branching pattern of PV were classified according to classification used by Covey et al (Covey AM, Brody LA, Getrajdman GI, Sofocleous CT, Brown KT. Incidence, patterns, and clinical relevance of variant portal vein anatomy. AJR Am J Roentgenol 2004; 183: 1055-64) and Koç et al (Koç Z, Oğuzkurt L, Ulusan S. Portal vein variations: clinical implications and frequencies in routine abdominal CT. Diagn Interv Radiol 2007; 13: 75-80). Normal anatomy (Type I) was seen in 773 patients (79.94%) out of 967 patients in our study. Trifurcation (Type II) anomaly was seen in 66 (6.83%) of cases. Right posterior vein as first branch of main PV (Type III) anomaly was seen in 48 (4.96%) of cases. Type IV anomaly and Type V anomaly was seen in 26 (2.69%) and 13 (1.34%) cases, respectively. 19 cases showed other types of variations. Variations in the hepatic PV branching patterns are commonly seen that are similar to variations in hepatic artery and biliary anatomy. Knowledge of these variations is extremely important for transplant surgeons and intervention radiologists. Awareness of the variations in PV branching patterns is essential for intervention radiologists and vascular surgeons and avoids major catastrophic events.

Pattern of branching of the left portal vein: an anatomo-radiological study

Branching variations of the left portal vein can be managed but they may require technical adaptation. The aim of the present study was to investigate the pattern of ramification of the left portal vein in vascular casts and in radiological images. 50 vascular casts and 200 computed tomography (CT) angiographies of the upper abdomen were analyzed. Analyses of the vascular casts and of the radiological images were conducted to evaluate the morphology of the left liver, the modality of division of the portal vein, and the number of branches destined for segments 2, 3, 4. In the vascular casts the portal vein presented bifurcation in 75%, trifurcation in 20%, and quadrifurcation in 5%, whereas in the radiological study the portal vein presented bifurcation in 90% and trifurcation in 10% of the cases. For segment 2 in the vascular casts, in their CT and in the radiologic in vivo study a number from 1 to 3 branches was found, coming from the medial or posterior aspects of the left portal vein. For segment 3 in the vascular casts, in their CT and in the radiologic in vivo study a number from 1 to 6 branches was found, coming from the posterior and medial aspects of the left portal vein and its the cul-de-sac. For segment 4 in the vascular casts, in their CT a number from 5 to 9 branches was found (in the radiologic in vivo study from 4 to 9), coming from the posterior and ventral aspects of the left portal vein and from its cul-de-sac. No branches were found to come from the lateral aspect of the left portal vein. Moreover, the modality of branching of the left portal vein correlated with the morphology of left liver. Knowledge of the pattern of branching of the left portal vein is important for surgical purpose. CT angiography is a valuable preoperative examination to visualize the branching pattern of adult patients.

Correlation Between Portal Vein Anatomy and Bile Duct Variation in 407 Living Liver Donors

Our aim was to determine whether variant bile duct (BD) anatomy is associated with portal vein (PV) and/or hepatic artery (HA) anatomy. We examined the associations between BD anatomy and PV and/or HA anatomy in 407 living donor transplantation donors. We also examined whether the right posterior BD (RPBD) course was associated with the PV and/or HA anatomy. Variant PV, HA and BD anatomies were found in 11%, 25% and 25%, respectively, of 407 donors enrolled in this study. The presence of a variant BD was more frequently associated with a variant PV than with a normal PV (61% vs. 20%, p < 0.0001). By contrast, the presence of a variant HA was not associated with a variant BD. A supraportal RPBD was found in 357 donors (88%) and an infraportal RPBD was found in 50 donors (12%). An infraportal RPBD was significantly more common in donors with a variant PV than in donors with a normal PV (30% vs. 10%, p = 0.0004). Variant PV, but not variant HA, anatomies were frequently associated with variant BD anatomy. Additionally, an infraportal RPBD was more common in donors with a variant PV than in donors with a normal PV.

Anatomical variations of donor portal vein in right lobe living donor liver transplantation: the safe use of variant portal veins

In right lobe (RL) living donor liver transplantation (LDLT), portal vein (PV) variations are of immense clinical significance. In this study, we describe in detail our PV reconstruction techniques in RL grafts with variant PV anatomy and evaluate the impact of accompanying biliary variations on the recipient outcomes. In a total of 386 RL LDLTs performed between July 2004 and July 2012, the clinical data on 52 (13%) transplants using RL grafts with variant PV anatomy were retrospectively analyzed. Portal vein anatomy was classified as type 2 in 20 patients, type 3 in 24 patients, and type 4 in eight patients. The PV reconstruction techniques utilized included back-wall plasty (n = 21), back-wall plasty with saphenous vein graft interposition (n = 6), saphenous vein graft interposition (n = 5), cryopreserved iliac vein Y-graft interposition (n = 6), and quiltplasty (n = 3). There was no donor mortality. In a median follow-up of 29 months, none of the recipients had vascular complications. Anomalous PV anatomy was associated with a high (54%) incidence of biliary variations; however, these variations did not result in increased biliary complication rate. Overall, the 1- and 3-year patient survival rates of recipients were 91% and 81%, respectively. Vascular and biliary variations in RL grafts render LDLT technically more challenging. By employing appropriate reconstruction techniques, it is possible to successfully use RL grafts with PV variations without endangering recipient and donor safety.

Feasibility of the Glissonian approach during right hepatectomy

ObjectiveThe Glissonian approach during hepatectomy is a selective vascular clamping procedure associated with low rates of technical failure and complications. The aim of the present study was to assess the feasibility of a right Glissonian approach in relation to portal vein anatomy. MethodsThis was a prospective study conducted over a 12‐month period, which included 32 patients for whom preoperative three‐dimensional reconstruction using contrast‐enhanced computed tomography in the portal venous phase and portography for right portal vein embolization were available, and in whom a right Glissonian approach was applied during right hepatectomy. Preoperative imaging data were correlated with intraoperative Doppler ultrasound findings (considered as the reference dataset). Causes of failures and complications specifically related to the Glissonian approach were identified. ResultsRight hepatectomy was performed for colorectal liver metastases (n = 25), hepatocellular carcinoma on cirrhosis (n = 6) and intrahepatic cholangiocarcinoma (n = 1). The Glissonian approach was effective in 24 (75%) patients. In the remaining eight (25%) patients, failure was caused by incomplete clamping (n = 2) or clamping of the left portal pedicle (n = 6). The portal anatomy was aberrant in six patients with failure, showing portal trifurcation (n = 1), right portal trifurcation (n = 1) and a common trunk between the right anterior and left portal branch (n = 4). An angle of less than 50 ° between the portal vein and left portal branch was reported in association with extended clamping to the left portal branch (selectivity = 72%, specificity = 71%). Intraoperative bleeding and biliary fistula occurred in two patients with non‐normal portal anatomy. ConclusionsThe right Glissonian approach was effective in 75% of patients. Failure of the procedure (including the extension of clamping to the left pedicle) mostly occurred in patients with portal vein variations, which can be accurately assessed using a combination of preoperative imaging and intraoperative Doppler ultrasound.

A retrospective evaluation of causes of exempting living liver donors in an Egyptian centre

Background and study aimsLiving-related liver transplantation has helped to solve the problem of shortage of deceased organ donors. However, studies showed significant donor complications occurring with adult living liver donation. This study aims at assessing different causes of exclusion of potent living donor transplantation in Egypt. Patients and methodsThe data of 158 living donors (corresponding to 50 consecutive transplanted cases) were retrospectively studied. ResultsOnly 50 donors were found to meet all the preoperative assessment criteria while 108 potential donors were excluded at various assessment steps. Majority of the excluded potential donors were due to anatomical variations (52/108) followed by hepatic steatosis (19/108) and positive hepatitis B or C virus serology (11/108). Regarding the anatomic variations, biliary anomalies were ranked as the first cause to exclude donors with the majority of them having the type C biliary variant. Portal vein variations were the second most common cause of exclusion due to portal vein trifurcation. Hepatic artery variations were detected in a lesser number of excluded donors. No donors were excluded for hepatic vein anomalies. ConclusionAnatomical variations are the most common causes to exempt living liver donors. Preoperative evaluation of anatomical variations, viral serology and hepatic steatosis plays the major role to accept or exclude the potential donors.

Right Posterior Portal Vein Stenosis Developed After Living Donor Liver Transplantation Using a Modified Right Lobe Graft With a Type 2 Portal Vein: A Case Report

Portal vein complications after liver transplantation (LT) can lead to graft liver failure. In this living donor liver transplantation case a stenosis developed in the right posterior branch of the portal vein of the graft liver from a living donor with type 2 portal vein variation. A 61-year-old woman diagnosed with hepatocellular carcinoma due to hepatitis B received a liver graft revealing a single lumen divided by a septum. The portal vein was anastomosed to the recipient portal vein without venoplasty. Postoperative Doppler sonogram revealed poor flow in the right posterior portal vein with compensatory arterial hyperperfusion. The postoperative computed tomography (CT) scan revealed narrowing of the proximal part of the right posterior portal vein with periportal tracking. Without intervention, the liver enzyme and bilirubin levels decreased to normal and the follow-up CT scan showed decreased periportal tracking. The patient was discharged without major complications. We believe that the posterior portal vein stenosis resulted from the direct anastomosis of the portal vein without a further venoplasty. Although there was no major complication due to the posterior portal vein stenosis in our patient, we suggest a venoplasty to prevent portal vein stenosis when using right lobe grafts with a type 2 portal vein, even if a single lumen is present and there is a margin for a direct anastomosis.

Living donor liver hilar variations: surgical approaches and implications

Varied vascular and biliary anatomies are common in the liver. Living donor hepatectomy requires precise recognition of the hilar anatomy. This study was undertaken to study donor vascular and biliary tract variations, surgical approaches and implications in living liver transplant patients. Two hundred living donor liver transplantations were performed at our institution between 2004 and 2009. All donors were evaluated by volumetric computerized tomography (CT), CT angiography and magnetic resonance cholangiography in the preoperative period. Intraoperative ultrasonography and cholangiography were carried out. Arterial, portal and biliary anatomies were classified according to the Michels, Cheng and Huang criteria. Classical hepatic arterial anatomy was observed in 129 (64.5%) of the 200 donors. Fifteen percent of the donors had variation in the portal vein. Normal biliary anatomy was found in 126 (63%) donors, and biliary tract variation in 70% of donors with portal vein variations. In recipients with single duct biliary anastomosis, 16 (14.4%) developed biliary leak, and 9 (8.1%) developed biliary stricture; however more than one biliary anastomosis increased recipient biliary complications. Donor vascular variations did not increase recipient vascular complications. Variant anatomy was not associated with an increase in donor morbidity. Living donor liver transplantation provides information about variant hilar anatomy. The success of the procedure depends on a careful approach to anatomical variations. When the deceased donor supply is inadequate, living donor transplantation is a life-saving alternative and is safe for the donor and recipient, even if the donor has variant hilar anatomy.

Anatomy of the right liver lobe: a surgical analysis in 124 consecutive living donors

Understanding anatomic variations of the right lobe is fundamental in adult to adult living donor liver transplantation. We analysed anatomy in 124 right liver (RL) donors. Portal vein: normal anatomy was found in 85.5% donors. In 14.5% the main right portal vein (PV) was absent. Hepatic artery: single arterial inflow of the RL was identified in 96% of donors. In 4% two arterial stumps were found. Bile duct: classic anatomy was identified in 50.8% of donors; 9.7% had a trifurcation of the common bile duct; in 7.2% the right anterior and in 15.3% the right posterior bile duct opened into the left bile duct; one segmental bile duct opened directly into the common bile duct in 12.1% and two segmental bile ducts in 4.8%. Hepatic veins (HV): in 74.3% the right HV was the single outflow; in 24.2% significant accessory HV (>5 mm) were preserved, in 2.4% the middle HV was harvested. We found that patients with PV variations had high incidence of multiple bile ducts (88.9%) while patients with single right PV had lower incidence (42.4%) (p = 0.00026). While anatomic variations in the RL donor were common, no contraindication to RL harvesting was noted in this study.

Biliary nut-craker syndrome caused by hilar biliary stricture due to portal vein variation

Benign biliary stricture is a challenging problem in hepatobiliary surgery. Benign biliary stricture is associated with major portal vein variation, which is not be found in literatures. A male patient with benign biliary stricture was admitted to the Chinese PLA General Hospital in March, 2010.The stricture was located in the hilar confluence with intrahepatic biliary dilation and hepatolithiasis. The result of computed tomography showed that the hilar biliary confluence was compressed by the left portal vein and right anterior portal vein. The patient was cured after receiving gallbladder interposition, choledocholithotomy and T tube drainage. We suggested that the benign hilar biliary stricture due to portal vein variation may be named as biliary nut-craker syndrome. Key words: Biliary nut-craker syndrome; Benign biliary stricture; Portal vein variation; Spiral computed tomography

Ultrasound examination of the liver: Variations in the vascular anatomy

The hepatic vasculature is highly complex. The hepatic artery (a branch of the celiac tripod) and the portal vein (formed by the confluence of the splenic and superior mesenteric veins) provide a dual blood supply while venous drainage is guaranteed by the hepatic veins. There are also numerous anatomic variants that can involve one or more of the system’s three components. Hepatic artery variants are the least common. Ten types have been identified, including several that are fairly frequent and others that are quite rare, and the variation generally involves the extrahepatic portion of the vessel. Portal vein variants are found in around 20% of the population. They can involve the main portal trunk or segmental branches. Variants of the hepatic veins are the most common. They involve the number and course (supernumerary veins) or the number, course, and openings (accessory veins). Knowledge of portal vein and hepatic vein variants, which are extremely common, is of prime importance for precise localization of lesions. Hepatic artery variants are equally important for surgical treatment of hepatic disease, especially liver transplantation, where it is essential for preoperative workup and postoperative follow-up of the recipient as well as for assessment of potential donors.

Identification of the anterior sectoral trunk with particular reference to the hepatic hilar plate and its clinical importance

At the hilum of the liver, there is a structure called the hilar plate, which is of great surgical importance because all variations in the bile ducts and blood vessels occur within this region. The Rex-Cantlie line does not always pass the point of portal bifurcation. Classifying portal vein (PV) variations based on the shape and origin of anterior sectoral trunk (AST) within the hepatic plate system will be of higher anatomical and surgical value than the conventional method based on PV ramification. We investigated PV variations in the hilar plate in terms of combinations of 4 hepatic sectoral trunks rather than successive ramification of the PV. The combination patterns of each sectoral trunk were analyzed using data from adult cadaver liver dissection (n = 64) and multi-detector computed tomography (n = 216) of human livers. The AST root position on the hilar plate varies, in contrast to the other sectoral trunks, which are relatively consistent in their root position. Three types of PV variations were identified based on the AST root position. In addition, 4 similar but different shapes (I, Y, V, and U) of AST were identified. Not only the root position in the hepatic hilar plate but also the shape of AST can be considered as the major determinants of PV variations.

Surgical Techniques According to Anatomic Variations in Living Donor Liver Transplantation Using the Right Lobe

Objectives In living donor liver transplantation, the right lobe has many anatomic variations in the vascular tree, which could lead to surgical complications. We need to define surgical technique according to anatomy. Methods From January 2000 to September 2007, 310 living donor liver transplantations using the right lobe were performed in patients with end-stage liver disease. The vascular trees were evaluated preoperatively with computed tomography and magnetic resonance angiography. We classified anatomic points for safe harvest in the hepatic artery, portal vein, and hepatic vein and described technical points based on anatomic variations. Result There were many anatomic variations in the hepatic vasculature. Hepatic artery variations were observed in 16.8% of cases. Double hepatic artery was observed in 14 cases (4.5%). Of these 14 cases, reconstruction as a single artery was performed in 6 and dual reconstruction was performed in 8 cases. Portal vein variation was observed in 45 cases (14.5%): Dual anastomosis to right and left portal vein was performed in type III ( n = 20; 6.4%) and type IV ( n = 3; 1.0%) variations. There were 70 cases of portal vein thrombosis. In 8 of the 70, a jump or interposition graft with iliac vein was utilized. Of the middle hepatic vein variant, segment V vein only was reconstructed in 188 (60.6%) cases. In 21 (6.8%) cases, segment VIII vein only was reconstructed, and in 43 (13.9%) cases, both segment V and segment VIII veins were reconstructed using the recipient's portal vein, a cryopreserved iliac vein, or a prosthetic graft. The most common variation of right inferior hepatic vein was type II ( n = 141; 45.5%), which has 1 right inferior hepatic vein. Conclusion Living donor liver transplantation using the right lobe can be performed safely, but there is a potential operative risk because of various anatomic variations. To minimize operative complications, anatomic variations should be kept in mind to ensure a safe and successful operation.

Preoperative Imaging Evaluation of Potential Living Liver Donors: Reasons for Exclusion From Donation in Adult Living Donor Liver Transplantation

Accurate pretransplant evaluation of a potential donor in living donor liver transplantation (LDLT) is essential in preventing postoperative liver failure and optimizing safety. The aim of this study was to investigate the reasons for exclusion from donation of potential donors in adult LDLT. From September 2003 to June 2006, 266 potential donors were evaluated for 215 recipients: 220 potential donors for 176 adult recipients; 46 for 39 pediatric recipients. Imaging modalities including Doppler ultrasound, computerized tomography (CT), and magnetic resonance (MR) angiography provided vascular evaluation and MR cholangiopancreatography to evaluate biliary anatomy. Calculation of liver volume and assessment of steatosis were performed by enhanced and nonenhanced CT, respectively. In the adult group, only 83 (37.7%) potential donors were considered suitable for LDLT. Of the 137 unsuitable potential donors, 36 (26.2%) candidates were canceled because of recipient issues that included death of 15 recipients (10.9%), main portal vein thrombosis (8%), recipient condition beyond surgery (5%), and no indication for liver transplantation due to disease improvement (2%). The remaining 101 (73.8%) candidates who were excluded included steatosis (27.7%), an inadequate remnant volume (57.4%), small-for-size graft (8.9%), HLA-homozygous donor leading to one-way donor–recipient HLA match (3%), psychosocial problems (4%), as well as variations of hepatic artery (4%), portal vein (1%), and biliary system anatomy (5%). Anatomic considerations were not the main reason for exclusion of potential donors. An inadequate remnant liver volume (<30%) is the crucial point for the adult LDLT decision.

Portal Vein Normal Anatomy and Variants: Implication for Liver Surgery and Portal Vein Embolization

The normal anatomy of the portal vein is defined as a division of the main portal vein into two branches-the left (supplying segments II, III, and IV) and right portal veins; the right dividing secondarily into two branches-the anterior (supplying segments V and VIII) and the posterior (supplying segments VI and VII) portal veins. Variants are frequent and account for 20 to 35% of the population. The most frequent variants are portal trifurcation with division of the main portal vein into the left, right anterior, and posterior branches, and the early origin of the right posterior branch directly from the portal vein. The presence of portal vein variants increases the risk of bile duct hilar anatomical variation. These variants must be diagnosed before complex hepatectomy, split or living donor transplantation, and before complex interventional procedures such as portal vein embolization. The purpose of this article is to review normal and variant portal venous anatomy and their implications for liver surgery and preoperative portal vein embolization.

3D Anatomical Variations of Hepatic Vasculature and Bile Duct for Right Lateral Sector of Liver with Special Reference to Transplantation

To achieve a safer living related liver transplantation (LRLT) using the right lateral sector, anatomical variations of the portal vein, hepatic artery and bile duct for the right lateral sector and their three dimentional (3D) relationship were assessed by integrated 3D-CT images. 52 patients who underwent contrast enhanced multi-detector row CT (MD-CT) and MD-CT cholangiography were enrolled. Data from contrast enhanced MD-CT were used to reconstruct the 3D images of the hepatic artery and portal vein. 3D images reconstructed from MD-CT data of the hepatic artery, portal vein and bile duct were integrated into a single image. The dual branching of the right lateral portal vein was observed in 22 (42.3%) patients. Three (5.8%) had dual right lateral ducts and 14 (26.9%) had dual right lateral arteries. Among them, "south-turning" artery and "north-turning" bile duct was observed in 22 (42.3%). "South-turning" artery and "south-turning" bile duct were 3 (5.8%). "North-turning" artery and "north-turning" bile duct were 2 (7.4%). Only 27 (51.9%) had single portal vein, bile duct and artery for the right lateral sector, those were preferable as candidates for right lateral sector graft transplantation. 3D anatomical variations of portal vein, artery and bile duct for the right lateral sector were complexed, and only half of the donor candidates had preferable hepatic structures for right lateral sector graft transplantation. Understanding of the 3D hepatic structures by 3D-CT may contribute to a better definition of anatomical contraindications for LRLT which may further results in more safe and widely applied right lateral sector graft LRLT.

Portal Venous System Aneurysms: Imaging, Clinical Findings, and a Possible New Etiologic Factor

The aims of this study were to present the prevalence, imaging and clinical findings, and possible causes of portal venous system aneurysms. From 1998 to 2006, a total of 38 portal venous system aneurysms identified in 25 patients were retrospectively reviewed. The data of seven patients diagnosed using color Doppler sonography or CT before March 2004 were not consecutive, but the data recorded thereafter comprised the analysis of 4,186 consecutive patients who underwent routine abdominal MDCT. The patients were 14 men and 11 women (mean age -/+ SD, 53 -/+ 17 years). The prevalence of portal venous system aneurysm among 4,186 consecutive patients was 0.43%. There were no differences with respect to patient age, patient sex, and intrahepatic or extrahepatic location of aneurysm between those with and those without portal venous system aneurysm. Seven of the 25 patients with portal venous system aneurysm were symptomatic because of portal vein thrombosis, and six of them had recurrence. These patients had significantly larger aneurysms than those without symptoms. Four of those seven symptomatic patients evaluated for thrombophilia had an underlying defect. Other associated findings were splenomegaly (n = 16), portal hypertension (n = 8), cirrhosis (n = 3), psoriasis (n = 2), portal vein variation (n = 1), chronic pancreatitis (n = 1), and cutis laxa (n =1). Portal venous system aneurysms were rare in our study group but occurred more frequently than previously thought. All thrombosed aneurysms, most with a recurrence, were symptomatic and larger in patients with symptoms of portal venous system aneurysm than in those without symptoms. There were no differences among patients with portal venous system aneurysm and those without portal venous system aneurysm with respect to patient age and patient sex. Among those with aneurysms, there was no difference between subjects with intrahepatic versus extrahepatic aneurysms. A thrombophilic defect probably played a role in development of thrombosis in the portal venous system aneurysm.

Prevalence of Right Portal Vein Branching Anomalies

Prevalence of Right Portal Vein Branching AnomaliesAnne M. Covey and Karen T. BrownAudio Available | Share

Venous variants and anomalies on routine abdominal multi-detector row CT

Objective This study aims to determine the types and prevalence rates of anatomic variations of the hepatic veins, portal vein, inferior vena cava and renal veins, and to establish statistical correlations between various anomalies and frequency differences between male and female using multi-detector row computed tomography (CT). Materials and methods One thousand one hundred and twenty patients (588 men, 532 women) were evaluated with routine abdominal CT. Frequencies of different variants were noted and compared, and correlations between three categories of variation were tested. Results In total, 1261 abdominal vein variants and anomalies were identified in 756 (67.5%) of 1120 patients. Six hundred and forty-two hepatic vein variants were detected in 468 (41.8%) patients. One or more inferior right hepatic veins were identified in 356 (31.8%) individuals, and tributary hepatic veins were detected in 147 (13.1%) patients. Portal vein variations and anomalies were observed in 307 (27.4%) cases. The most frequent of these was trifurcation (139 patients, 12.4%). A total of 311 inferior vena cava and renal vein variants were identified in 258 (23%) cases. Six patients (0.5%) exhibited inferior vena cava anomalies, 62 (5.5%) had circumaortic renal veins, 53 (4.7%) had retroaortic renal veins, and 210 (18.8%) had multiple renal veins. Conclusion The prevalence of abdominal vein variations is high, and routine abdominal CT demonstrates these abnormalities very well. The data suggest that hepatic vein variants and multiple right renal veins are more frequent in women than in men, and that hepatic vein variation is correlated with portal vein variation.

Types and Frequencies of Biliary Tract Variations Associated with a Major Portal Venous Anomaly: Analysis with Multi–Detector Row CT Cholangiography

To retrospectively determine whether major portal venous variation was more frequently associated with biliary variants, with consideration of the types and frequencies of biliary tract variations in the right and left liver lobes. Before undergoing computed tomographic (CT) cholangiography, patients gave informed consent. The retrospective research protocol was approved, and informed consent was waived by the ethics committee. Forty-four patients aged 29-80 years who underwent multi-detector row CT cholangiography had a major portal vein variation in which the main portal vein diverged into the common trunk of the left portal vein and right anterior sectorial portal vein. One hundred fifty-eight consecutive patients aged 26-89 years who did not have this variation served as the control group. Three radiologists retrospectively evaluated the confluence pattern of the bile duct, the relationship between this pattern and the portal vein, and the major branching pattern of the portal vein. Pearson chi2 and Fisher exact tests were performed to identify significant differences between the two patient groups. The classic hilar confluence pattern, where the right posterior sectorial duct connects supraportally with the right anterior sectorial duct, was less frequent in the patients with the portal vein variation than in the control subjects (32% vs 73%, P < .05). The following biliary tract variations were identified more frequently in the variation group than in the control group (P < .05): right posterior sectorial duct joining left hepatic duct with a supraportal course (34% vs 12%), right posterior sectorial duct joining right anterior sectorial duct with an infraportal course (13% vs 4%), right posterior sectorial duct following an infraportal course (23% vs 8%), and left lateral segmental ducts caudal to the umbilical portion of the portal vein (14% vs 3%). The right hepatic duct, which receives all biliary ducts from the right lobe, was significantly less frequently developed in the variation group (46% vs 79%, P < .05). In addition, retroportal bile ducts were seen in four patients with the portal vein variation (P < .05). Bile duct configurations in patients with portal vein variation were significantly different from those in control subjects.