Sequential Changes of Attenuation Values of Bile Duct and Gallbladder on CT after Oral Contrast Ingestion

ABSTRACT

PURPOSE: The purpose of this study is to evaluate that sequential CT scans after oral contrast ingestion can show morphological and functional status of the biliary tree, especially for the gallbladder and assess whether the CT scans demonstrate other radiological informations than conventional oral cholecystography. MATERIALS AND METHODS: Thirty volunteers in third decades and eight patients with hepatobiliary disease were included for the study. CT scans were obtained 3, 6, 9, 12 hours after oral contrast ingestion and thirty minutes after fat meal in thiry volunteers. Conventional oral cholecystography was also obtained in all volunteers at 12 hours after oral contrast ingestion and after fat meal. We evaluate opacification of gallbladder, biliary tree, and duodenum by contrast media on CT scans and attenuation values of gallbladder, common hepatic duct and common bile duct in each artatomic area on CT and its sequential change. CT scans were performed 6 hours after oral contrast ingestion in eight patients with hepatobiliary disease. And gallbladder function was evaluated by opacification of gallbladder by contrast media in all patients. RESULTS: In thirty volunteers, opacified gallbladder by contrast media was seen in all cases in all sequential periods of time on CT scans, but in 22 cases on conventional oral cholecystography. Contrast-filled intrahepatic ducts were demonstrated in 3 cases at 3 hours after oral contrast ingestion and 11 cases at 6 hours and were not seen thereafter. Contrast-filled common hepatic duct was noted in 28, 18 and 4 cases respectively at 3, 6 and 9 hours after oral contrast ingestion and the CT attenuation values of common hepatic ducts had become progressively decreased. Contrast-filled common bile duct was noted in 28, 18 and 4 cases respectively at 3, 6 and 9 hours and the CT attenuation values of common bile ducts were not changed untill 9 hours but slightly increased at 12 hours. Contrast media was noted in 7, 5, 6 and 5 cases at 3, 6, 9, and 12 hours in cystic duct and 8, 3, 2, 5 cases in duodenum. Contrast-filled cystic duct and duodenum were noted in 24 cases and 19 cases respectively on CT scans after fat meal. The CT attenuation values of gallbladder were increased in sequential periods of time and the difference of density of gallbladder between 3 hours and 6 hours was statistically significant(p=0.0001). The CT attenuation values of gallbladder at 6 hours were heighter than that in 3 hours, statistically. Opacified gallbladder were noted in 2 cases of fatty liver(n=2), 1 case of alcoholic liver disease(n=1), in 1 case of liver cirrhosis(n=1). Patients of gallbladder stone(n=2) or hepatocellular carcinoma (n=2) had non-opacified gallbladder on CT scans. CONCLUSION: The CT scans after oral contrast ingestion can show the morphological and functional aspects of gallbladder better than conventional oral cholecystography and can also show biliary trees and other surrounding structures, so it is helpful method for assessment of not only gallbladder diseases but also other hepatobiliary diseases.