A New Classification of the Right Portal Vein Using 64 Channel Multi-dectector CT (MDCT)

ABSTRACT

PURPOSE: Portal branching patterns (ramification) that differ from those previously described are occasionally encountered during liver surgery. We studied the portal vein branching patterns by performing 64 MDCT. METHODS: A total of 100 patients with normal liver underwent MDCT during arterial portography. Next, the 3 dimensional portograms were reconstructed and the portal branching patterns were assessed. RESULTS: In 80 (80%) of the 100 patients we examined, the right anterior portal vein bifurcated into the ventral and dorsal branches. Only 20 percent of the patients showed the classic pattern, that is, bifurcating into the right anterior superior (P8) and right anterior inferior branches (P5). The portal branches in segment 5 showed many variations in their origins and numbers. The portal branches in segment 7 originated from both the right anterior and posterior portal veins, and not just the right posterior portal vein. CONCLUSION: Instead of dividing the right liver into the superior and inferior segments, we proposed that the right liver can be divided into 3 segments, which are designated as the right anterior, middle and posterior segments. In the view of the vascular watershed, the division of the right anterior and posterior sections by using the right hepatic vein might be inaccurate.