Contraction and evacuation of the gallbladder studied simultaneously by ultrasonography and 99mTc-labeled diethyl-iminodiacetic acid scintigraphy.

Emptying of the gallbladder was studied by the simultaneous use of 99mTc-labeled diethyl-iminodiacetic acid [HIDA] scanning and real-time ultrasonography. In response to a liquid test meal the gallbladder volume was reduced for 80 min and then increased again, but the radionuclide evacuation continued and was more complete than could be explained by the reduction of gallbladder volume. In response to intravenous infusion of cholecystokinin, a maximal contraction of the gallbladder to 35% of the basal volume was obtained at 40 min, and 36% of the HIDA then remained in the gallbladder. In a separate series repeated intravenous injections of 99mTc-HIDA were given after the test meal, and the isotope was found to enter the gallbladder even when the gallbladder contracted. The results support the view that the gallbladder acts like a 'bellows' when contracting and that postprandial fluid secretion by the gallbladder mucosa may help to evacuate its contents.