Portal venous variations. Prevalence with contrast-enhanced helical CT

Incidence of Extrahepatic Portal Vein Anatomic Variations and Their Clinical Implications in Daily Practice

Anatomical variations of the portal vein are relatively common and can affect the outcomes of hepatic resections, transplantations and interventional radiological procedures. The aim of this study was to review the literature regarding extrahepatic portal vein anomalies. Two main databases were searched for suitable articles, and results concerning more than 3,700 patients were included in the analysis. The most common anatomical variations of the portal vein were trifurcation and having a right posterior portal vein as the first branch of the main portal vein; these anomalies were found in 11.7% and 10.8% of cases, respectively.

Unusual Branching Pattern of the Portal Vein: Its Importance

Portal vein anatomy and its branching pattern are of utmost importance for surgical planning of complex liver resections, living donor liver transplant and radiological procedures. The division of the vein at the porta hepatis, into the right and left branches is the most common branching pattern. Various branching variations have been described. We report a previously undescribed branching pattern of the right portal vein, where the segment VII vein arises directly from the left portal vein.

CT virtual endoscopy for analyzing variations in the hepatic portal vein

PURPOSE

To evaluate the value of CT virtual endoscopy (CTVE) for accurately distinguishing varying types of portal veins (PVs).

MATERIALS AND METHODS

From 526 consecutive patients whose hepatic portal vein was well visualized, patients who were considered to have trifurcation of the main portal vein (MPV) or right portal vein (RPV) on volume rendering (VR) and maximum intensity projection (MIP) imaging were chosen for the analysis. Two radiologists evaluated the PV anatomy of these patients and re-classified the types of PV variation using the CTVE technique. The Wilcoxon rank sum test was used to calculate differences in age between males and females.

RESULTS

Thirty-two patients (20 males, 12 females; age range 21-68 years; mean age 43 years) were considered to have trifurcation of the MPV (15) or RPV (17) on VR and MIP imaging. Fifteen patients in total had a trifurcation confirmed by CTVE (6 patients were proven to have an MPV trifurcation by CTVE, and 9 were confirmed to have a RPV trifurcation).

CONCLUSIONS

CTVE can differentiate PV variations that cannot be identified accurately on MIP and VR.

Vascular and biliary anatomy of the right hilar window: its impact on recipient morbidity and mortality for right graft live donor liver transplantation

BACKGROUND

Intrahepatic anatomic variations have been associated with both morbidity and mortality associated with live donor liver transplantation. The aim of our study was to evaluate central hilar and peripheral segmental vascular/biliary anatomy in right graft living donor liver transplantation.

METHODS

From January 2003 to August 2007, three-dimensional (3D) computed tomography (CT) reconstructions and virtual 3D hepatectomies were performed in 71 consecutive right graft live liver donors. A combined two-level classification system addressing the four possible combinations of normal (N) and abnormal (A) central hilar and peripheral features based on both the existing classification and our own classification for portal (portal vein, PV), arterial (hepatic artery, HA) and biliary (bile duct, BD) systems was defined as follows: type I, N/N; type II, N/A; type III, A/N; and type IV, A/A.

RESULTS

A simultaneous normal central hilar and peripheral segmental (N/N) anatomy for each system (PV, HA, BD) was found in <50% of grafts. The highest incidence of complex vascular and biliary reconstructions was observed with grafts having abnormal central (type III) or combined abnormal central/peripheral (type IV) anatomy. Central hilar arterial and biliary anomalies were predictors of morbidity by both univariable and multivariable analyses.

CONCLUSIONS

Our two-level classification and 3D imaging techniques allowed a cautious surgical approach in high-risk cases. Central hilar anatomic variants of the arterial and biliary systems were associated with increased morbidity. Further randomized trials will help determine the precise extent of our observations.

Three-dimensional contrast-enhanced MR angiography in diagnosis of portal vein involvement by hepatic tumors

AIM: To assess the accuracy of three-dimensional contrast-enhanced magnetic resonance angiography (3D CE MRA) in evaluation of the portal vein involvement in patients with hepatic tumors.

METHODS: 3D CE MRA was performed in 62 patients with hepatic tumors to assess the patency of the main, right and left portal veins before hepatic surgery. A total of 186 veins were examined for encasement, occlusion and tumor thrombosis. The results of 3D CE MRA diagnosis were then correlated with the surgical-pathological and intra-operative sonographic findings.

RESULTS: 3D CE MRA correctly detected 48 of 49 involved and 135 of 137 noninvolved portal veins with the sensitivity of 98%, specificity of 99%, positive predictive value of 96% and negative predictive value of 99%.

CONCLUSION: 3D CE MRA is accurate in evaluation of the portal vein involvement in patients with hepatic tumors.