RADIOLOGY: HEPATOBILIARY: Case# 33663: ACUTE CHOLECYSTITIS. A 56 year old gentleman with upper abdominal pain and an ultrasound of the gallbladder that demonstrated a thickened wall with distension. Hepatic uptake of the radiopharmaceutical (5 mCi of Tc-99m DISOFENIN) was rapid, suggesting adequate liver function. Excretion into the duodenum excluded a complete common duct obstruction. No filling of the gallbladder was noted by 60 minutes. Intravenous morphine sulfate (.04 mg/kg) was administered and an image 30 minutes later failed to demonstrate filling of the gallbladder. Hepatobiliary scans are useful in determining the patency of the cystic duct. An occluded cystic duct is the hallmark of acute cholecystitis. Failure of the technetium-99m n-iminodiacetic acid to fill the gallbladder implies an occluded duct. Chronic cholecystitis can also demonstrate an initial absence of filling; however, delayed images at 4 hours usually demonstrate gallbladder filling. Recently, a morphine augmented study design has been introduced to shorten the overall study time. If no gallbladder is visualized after one hour and no common duct obstruction is noted, morphine is given to constrict the sphincter of Oddi, increasing the intraductal pressure. Non filling of the gallbladder 30 minutes after morphine injection confirms acute cholecystitis. Sensitivities and specificities of morphine augmented hepatobiliary studies are 96% and 87%, respectively. Patient Prep: No meal 3-4 hours prior to study, and patients with prolonged fasting > 48 hours are intravenously injected with sincalide (0.02 ug/kg) 30 minutes prior to the study.