We compared the detectability and conspicuity of minimum intensity projection CT cholangiography (Min-IP CTC)with volume rendering CT cholangiography (VRCTC).The subjects were ten patients (6 men, 4 women, mean age 64.7) who clinically suspected obstructive biliary truct disease. They underwent enhanced helical CT. Volume data of delayed phase that reconstructed by 2 or 1 mm thickness was transferred to work station (Advantage Windows) and data processing by Minimum Intensity Projection (Min-IP) and Volume Rendering(VR) was done. Three radiologists compared the conspicuity and detectability of the obstructive portion and conspicuity intrahepatic bile duct on Min-IP CTC with that on VRCTC. Both VRCTC and Min-IP CTC had the same detectability of obstructive point (90 %). VRCRC was superior to Min-IP CTC in conspicuity of the obstructive point (40 % vs. 10 %), and Min-IP CTC was good in conspicuity of the intrahepatic bile duct (80 % vs. 0 %). We considered that Min-IP CTC and VRCTC were constructed from conventional enhanced helical CT data without adding special technique in the evaluation of the occlusive biliary tract disease. These 3D-CTC were useful diagnostic maneuver which could make up for each other
