Classical findings: small bowel obstruction; gas in biliary tree; large ectopic gallstone (Rigler triad).

Other findings: collapsed gallbladder; gas in gallbladder.

Terminology: mechanical intestinal obstuction caused by impaction of one or more gallstones.

Pathology: occurs in setting of chronic cholecystitis or following multiple ERCPs. Risk increases with age.

Reference: Federle M. Jeffrey R. Desser T. Diagnostic Imaging: Abdomen 2004. Amirsys. Canada.

Credit: Dr Marina-Portia Anthonyhttp://www.radpod.org