Is cholecystokinin administration during hepatobiliary imaging a physiologic test?

Objectives: Hepatobiliary scintigraphy with cholecystokinin (CCK) is a well-established test for chronic cholecystitis and gallbladder motility disorders. Many studies have compared the effects of fatty meal versus CCK administration on gallbladder contractility in different patient populations and have concluded that they are comparable. The aim of this study is to evaluate the effect of CCK and half and half milk consecutively administered in the same patient on gallbladder contractility.

Methods: A total of 147 patients underwent a standard hepatobiliary imaging for one hour after administration of 5.0 mCi of Tc-99m Mebrofenin intravenously. If the gallbladder was visualized, the patients were injected slowly with 0.02 ug/kg of CCK over 3 minutes and additional 30 minutes of dynamic imaging was obtained. Patients with gallbladder ejection fraction (GBEF) of less than 35% after CCK stimulation were prospectively included in this study. After consenting to participate in the study, the patient was administered 8 oz of half and half milk orally. This was followed by 15 minutes wait and subsequent additional 30 minutes of dynamic imaging. The GBEF was recalculated after milk administration. The GBEF after CCK was compared with GBEF after milk ingestion. The number of patients with a change of their GBEF from below 35% (abnormal) to above 35% (normal) was recorded.

Results: Out of 147 patients, 23 patients (17 females, 6 males) had abnormal GBEF and were included in this study with an average age of 42.6y. The average GBEF after CCK administration was 13 + 0.07% (range 0 - 26%). The recalculated average GBEF after milk administration was 27 + 0.20% (range 2 - 78%). The average increase in GBEF with the administration of milk after CCK was 14 + 0.23% (range 0 -78%). The GBEF changed from abnormal (GBEF < 35%) to normal (GBEF >35%) in six patients (26%) out of the 23 patients. The remaining 17 patients had an increase in their GBEF at an average of 17 + 0.08% but remained abnormal. Only one patient had pain after CCK administration and was one of those who changed their GBEF from abnormal to normal after adding milk. Another patient had abdominal pain after milk ingestion and her GBEF remained abnormal with both CCK alone and CCK followed by milk.

Conclusion: CCK administration alone over 3 minutes during hepatobiliary scintigraphy is insufficient and non-physiologic for the evaluation of gallbladder contractility. Research Support: