Gallbladder response to a second dose of cholecystokinin during the same imaging study.

Patients on total parenteral nutrition or after prolonged fasting may require treatment with cholecystokinin (CCK) prior to hepatobiliary imaging. Some may also require evaluation of gallbladder (GB) contractility, and the need for a second dose of CCK may arise. It is not clear whether gallbladder function can be adequately evaluated with CCK when a previous CCK dose had already been administered. We studied ten normal subjects to evaluate GB response to a second CCK injection. The subjects received 20 micrograms/kg sincalide in a 3-min infusion prior to administration of technetium-99m disofenin. They then received an identical sincalide dose at 60 min postinjection, and imaging was continued for another 30 min to quantify GB contraction. Gallbladder ejection fraction (GBEF) values ranged from 42-98% (mean: 71.5 +/- 19%). Pretreatment with CCK does not preclude GB contraction evaluation with a second dose of CCK. Expected GBEF values are similar to those obtained with single CCK injections.