Figure 15. Three-dimensional VR image (inferior oblique view) from CT angiographic data demonstrates trifurcation of the portal vein (curved solid arrow) into the right anterior (straight solid arrow), right posterior (arrowhead), and left portal (open arrow) veins. Thus, in cases of right lobe tumor, these three latter veins must be ligated individually to preserve the portal venous supply to the left hepatic lobe.