Differentiation of complicated cholecystitis from gallbladder carcinoma by computed tomography.

Differentiation between complicated cholecystitis and advanced gallbladder carcinoma can be difficult when clinical findings are confusing. Computed tomographic (CT) scans were reviewed from 22 patients with a surgical diagnosis of complicated cholecystitis (11 cases) or advanced gallbladder carcinoma (11 cases). The presence of a curvilinear low-attenuation "halo" around the gallbladder wall was specific for complicated cholecystitis. Findings indicative of gallbladder carcinoma included a focal soft-tissue mass, biliary obstruction at the level of the porta hepatis, and direct hepatic invasion or metastases. Other findings, such as diffuse wall thickening, streaky soft-tissue densities in the pericholecystic fat, and thickening of the hepatoduodenal ligament, could be seen in both entities and, therefore, were less useful in differentiating these two disease processes. Knowledge of these differential CT findings may result in a more accurate preoperative diagnosis.