A tomographic evaluation of the non-visualised oral cholecystogram.

Tomographic examination was carried out on 27 patients in whom there was no opacification of the gallbladder after routine cholecystography using a double dose of contrast medium. Decisive findings were present in 24 of these cases. The findings included the presence of radiolucent and opaque calculi within the gallbladder, or within the common bile duct, and dilatation of the common bile duct. In the three cases in which no information was gained by tomography, cystic duct obstruction was found at operation.