Helical contrast-enhanced CT image of a dog with a cholangiocarcinoma.Axial CT image showing multiple lobulated non-enhancing hypoattenuating masses in the caudate and left lateral lobe of the liver which were histopathologically confirmed as cholangiocarcinoma. Note how the tumor encases the intrahepatic portal branch and reduces the vessel’s diameter (arrows). The CVC is severely flattened and compressed by the mass effect of the tumor. There is a concomitant mild periportal halo seen in the periphery of the left lateral lobe (arrow head). Abbreviations: CT, Computed Tomography; PV, portal vein; CVC, caudal vena cava, Ao, Aorta; CL, caudate lobe; LLL, left lateral lobe.