Most informative projection for portography: quantitative analysis of 47 percutaneous transhepatic portograms.

The goal of this study was to determine which projection for percutaneous transhepatic portography best depicts the anatomy of the proximal portal vein. Portograms ( n = 47) obtained in the anteroposterior, right anterior oblique, and right anterior caudal oblique projections were analyzed retrospectively. Lengths of the right portal trunk, the transverse portion of the left portal vein, and the right anterior and posterior portal branches, as well as angles between the right portal trunk and the transverse portion of the left portal vein and between the right anterior and posterior portal branches were measured in the various projections. Differences were evaluated using analysis of variance with Scheffe's method. The transverse portion of the left portal vein and the right anterior and posterior portal branches appeared longer on the right anterior caudal oblique views than on the anteroposterior ( p < 0.0001, < 0.0001, < 0.0001) or right anterior oblique ( p < 0.0001, = 0.001, < 0.0001) views. The angle between the right portal trunk and the transverse portion of the left portal vein was wider on the right anterior oblique views than on the anteroposterior ( p < 0.0001) or right anterior caudal oblique ( p = 0.007) views. The angle between the right anterior and posterior portal branches was wider on the right anterior caudal oblique views than on the anteroposterior ( p < 0.0001) or right anterior oblique ( p = 0.030) views. The right anterior caudal oblique projection provides the best image of the proximal portal vein, and therefore should be obtained whenever possible in preoperative staging of hepatobiliary cancer.