Normal values of gallbladder ejection fraction using 99mTc-sestamibi scintigraphy after a fatty meal formula

Sincalide, in conjunction with cholescintigraphy, is necessary for the diagnosis of chronic acalculous cholecystitis. However sincalide is not widely available. This study investigates the use of a commercially available formula as an inexpensive alternative to sincalide, containing a sufficient and known amount of fat to cause gallbladder contraction, and to determine normal gallbladder ejection fraction (GBEF) values.

We studied 36 patients aged 51.7+/- 10.9 years with body mass index 26.7+/- 5.2 who were referred for 99mTc-sestamibi myocardial perfusion imaging. They did not have any abdominal symptoms, or history of abdominal disease and were not taking any medication known to affect the biliary tract. All were prescreened with a hepatobiliary ultrasonography to exclude any abnormality. After 6 hours fasting, 20 mCi of 99mTc-sestamibi was injected intravenously at rest and 90 minutes later the subjects ingested a test meal (10 g fat). GBEF was calculated at 30 and 60 minutes after fatty meal ingestion.

GBEF at 30 minutes and at 60 minutes after fatty meal ingestion were 69.54+/- 21.04% and 84.26+/-11.41%, respectively. GBEF did not differ significantly between men and women. There was no statistically significant correlation between BMI and GBEF. No significant difference was noticed in GBEF between obese, overweight and normal weight patient groups.

Lower limit of normal GBEF values was 27.46% at 30 min and 61.44% at 60 min using a standard fatty meal. It is possible to report the results of a GBEF measurement after fatty meal in terms of the percentile rank, compared with subjects without biliary disease.