Impression on CHD is often concave to the right
• MR: Dilated CHD and intrahepatic ducts with stricture at level of stone (signal void on all pulse sequences)
• US: Large, immobile gallstone impacted in cystic duct or infundibulum with dilated intrahepatic ducts













IMAGING
General Features
CT Findings
• Imaging findings similar to MR or US, with large stone in cystic duct, focal narrowing of CHD at level of stone, and biliary dilatation upstream from level of stone
DIFFERENTIAL DIAGNOSIS
Choledocholithiasis
PATHOLOGY
General Features
• Etiology
Impaction of stone in cystic duct, infundibulum, or Hartmann pouch compressing bile duct at same level
Obstruction caused by either direct mass effect (extrinsic compression or erosion into bile duct) or secondary development of stricture in CHD due to inflammation from stone


Staging, Grading, & Classification
• Csendes classification (1989)
Type II (∼ 25% of cases): Cholecystocholedochal fistula involving < 1/3 circumference of ductal wall
Type III (∼ 13% of cases): Cholecystocholedochal fistula involving 1/3-2/3 circumference of ductal wall


CLINICAL ISSUES
Presentation
Treatment
• Stent placement during ERCP may be temporary option prior to surgery but is not definitive therapy
















