We performed IV bolus CT scan in 40 patients with final diagnosis of various hepatic masses in order to evaluated hemodynamic changes and changes and differentiating characters of the lesions. Preenhanced, early and late phase post enhanced, and delayed CT scans were obtained with rapid IV bolus injection of contrast materials and table sliding method for pertinent scans. In hepatomas, early enhanced CT scan directly showed hypervascular change and active viable portion of the mss and late phase CT scan showed capsular enhancement. In addition, extracapsular in vasion and post-embolization recurrence were more easily visualized. In hemangiomas, early and late enhancing types could be categorized according to the time of maximal enhancement. In metastatic liver malignancies and cholangiocarcinomas, specific findings were seen in early phase and delayed CT scans and not in convntional CT scan. In conclusion, IV bolus CT scan is a very useful CT method in demonstrating the charac eristic hemodynamic patterns and in differential diagnosis of the hepatic masses.