Cholecystokinin, or CCK, is a hormone produced by cells in the upper small intestine in response to the presence of fat and protein in food. Its primary actions include stimulating the gallbladder to contract and release bile into the duodenum and causing the pancreas to secrete digestive enzymes. In diagnostic imaging, a synthetic form of CCK is sometimes administered intravenously during a gallbladder ejection fraction study to assess how well the gallbladder contracts. On ultrasound, the administration of CCK can be used to observe gallbladder contraction in real time, and a gallbladder that fails to contract normally may suggest biliary dyskinesia, a condition that causes gallbladder symptoms despite the absence of gallstones.
Sonography Term