The Radiological Differentiation of Hypervascular Intrahepatic Cholangiocarcinoma from Hepatocellular Carcinoma with a Focus on the CT Value on Multi-phase Enhanced CT

Background/Aim: This study aimed to investigate whether hypervascular intrahepatic cholangiocarcinoma (HICC) can be differentiated from hepatocellular carcinoma (HCC). Materials and Methods: Among 100 patients with intrahepatic cholangiocarcinoma, 22 patients were diagnosed with HICC based on the computed tomography (CT) value in the late arterial phase as follows: the CT value of the tumor >= that of the liver parenchyma. The CT values of the HICC were compared to those of HCC cases (n=120). Results: The CT value of HICC was lower in the unenhanced phase (UP) (p=0.016) and higher in the equilibrium phase (EP) (p<0.001) in comparison to HCC. The non-tumorous liver (odds ratio [OR]: 6.35, p=0.002) and an E/U ratio (the mean CT value of the tumor in the EP to that in the UP) of >2.3 (OR=13.1, p<0.001) were independent diagnostic factors for differentiating HICC from HCC. Conclusion: E/U ratio is useful for differentiating between HICC and HCC.