Biliary malignancy: Value of arterial, pancreatic, and hepatic phase imaging with multidetector-row computed tomography

Objective: To assess the diagnostic value of arterial, pancreatic, and hepatic phase imaging with multidetector-row computed tomography of a bile duct malignancy. Methods: Our institutional review board approved this retrospective study and waived the requirement for informed consent. Forty-two patients with surgically proven hilar or extrahepatic cholangiocarcinoma, who underwent preoperative imaging with triple-phasic multidetector-row computed tomography, were included in this study. Images obtained during each phase were reviewed by 2 independent observers who assessed the tumor conspicuity and the biliary extent of the tumor and vascular invasion by the tumor. For quantitative analysis, another radiologist measured the tumor attenuation, the normal liver parenchyma, the aorta, and the main portal vein on each phase image. Results: The degree of tumor conspicuity was higher in the pancreatic and hepatic phases than in the arterial phase (P < 0.01); however, there was no statistical difference in tumor conspicuity between the pancreatic and hepatic phases (P > 0.05). The mean tumor attenuation was greater in the hepatic phase at 114.2 +/- 24.6 Hounsfield units versus 72.9 +/- 18.3 Hounsfield units in the arterial phase (P < 0.001). The images obtained in the hepatic phases were significantly superior to those obtained in the arterial phase for predicting the tumor involvement into the secondary biliary confluence (P < 0.05). In predicting for the vascular involvement by the tumors, there was no significant difference among the 3 enhancement phases (P > 0.05). Conclusions: Routine acquisition of arterial phase images is not necessary for successful detection and evaluation of the extent of hilar or extrahepatic bile duct carcinoma.