Figure 4. Pancreatic head carcinoma.(a,b) Consecutive axial images showed the portal vein (PV) vessel calibre (arrow) was changed, although it was surrounded less than 50% of the vessel circumference by tumour. (c) Volume rendering (VR) 3D image showed that a segment of PV was stenosed. The axial images also showed that the common hepatic artery (CHA) was embedded in tumour and the coeliac artery (CA) was surrounded by more than 50% of the vessel circumference. PV, CHA and CA were proven to be infiltrated at surgical exploration.