MR and CT cholangiography in evaluation of the biliary tract

Objective: To compare MR and CT cholangiography (MRC and CTC) in evaluating the anatomy of the extrahepatic biliary tract and the pathology related to the gallbladder. Material and Methods: Twenty-three patients underwent MRC and CTC with a biliary contrast medium for investigation of biliary disease. 3D displays of both were also obtained. Endoscopic retrograde cholangiography was performed in 17 patients, and the pathology of all 23 was evaluated. Results. Overall, the image quality was higher with CTC than with MRC (4.7 vs 3.9, p < 0.05). The cystic duct was demonstrated better by CTC than MRC (p < 0.05). Multiplanar reformation (MPR) and source images provided additional information to that obtained from 3D MRC and CTC images. Gallstones were revealed in 6 patients by CTC and in 5 of these 6 by MRC. In 2 patients with cholecystitis, CTC demonstrated gallbladder wall thickening but MRC did not. In 3 patients with adenomyomatosis, MRC demonstrated Rokitansky-Aschoff sinuses (RAS) while CTC demonstrated focal gallbladder wall thickening in all 3 and RAS in 1 of them. Conclusion: Both MRC and CTC provided anatomical and pathological information about the biliary system. With both techniques, however, either MPR or source images proved necessary in addition for evaluating the biliary system anatomy and pathology. The gallbladder wall was depicted clearly in source CTC, but MRC is recommended for the evaluation of adenomyomatosis because it depicts RAS clearly.