Halo around the gallbladder--a prognostic sign?

The implications of the finding of a sonolucent zone around the gallbladder, characterized on ultrasonography by loss of definition of the outer (serosal) aspect of the gallbladder wall with a moderately well defined inner (mucosal) surface in patients with signs and symptoms of acute cholecystitis, are described. Of the nine consecutive patients with this finding, five were found to have gangrenous cholecystitis and/or perforation of the gallbladder at surgery. Four of these patients were operated upon within 24 hours of the ultrasound study, one 19 days later. The pathologic basis for this finding is thought to represent massive thickening of the gallbladder wall, with a possible contribution from adherent edematous omentum in the region of the fundus of the gallbladder. Thus this finding of a sonolucent halo about the gallbladder was important in our series, being frequently an indicator of acute cholecystitis complicated by gangrene with or without perforation of the gallbladder.