[Focal sparing around the gallbladder in fatty liver: an useful sign in the diagnosis of borderline cases by CT].

The role of CT in the diagnosis of fatty liver is well established. CT has been proved to be a useful noninvasive tool for the demonstration of fatty infiltration of the liver. The characteristic finding is a diffuse decrease in the attenuation within the liver compared with that of the spleen. Commonly, fatty infiltration of the liver is generalized and both CT scans and sonograms can easily demonstrate changes related to this condition. Sometimes, fatty infiltration of the liver is focal and occasionally, it is generalized with focal sparing of the normal liver tissue creating some problems in the diagnosis. Recently, some reports have mentioned the appearance of a focal sparing area in the generalized fatty liver. We often found a high attenuation region around the gallbladder bed in the fatty liver patients on CT examination. There appears to be some relationship between the high density around the gallbladder area and the fatty liver. A retrospective study was undertaken to evaluate the relationship. In this paper, we presented the CT scans of 57 fatty liver cases and compared them with the CT scans of 50 normal patients to discuss the possible cause of the phenomenon and its usage in the diagnosis of the fatty liver.