FDG-PET/CT in the Evaluation of Patients With Suspected Cholecystitis

Hepatobiliary iminodiacetic acid (HIDA) scan scintigraphy is a nuclear medicine scan used to evaluate patients suspected of having acute cholecystitis (infection/inflammation of the gallbladder). Because it is an indirect test that looks for obstruction of the cystic duct structure, there are many causes for a false-positive HIDA study. There is a need for a more sensitive and specific test that can accurately assess gallbladder infection and/or inflammation. The purpose of this study is to determine the effectiveness of fluorodeoxyglucose (FDG) as a direct means of detecting patients with acute cholecystitis. FDG is an imaging agent that has previously been shown to accumulate in areas of infection and/or inflammation. The location and intensity of FDG accumulation in the body can be detected with a camera system called a "positron emission tomography" (PET) camera. In theory, this test should be effective in detecting acute infection and/or inflammation of the gallbladder. Consenting participants will receive injection of FDG one hour prior to the FDG-PET/CT examination. The participant will then be imaged using a PET/CT machine, which is a special camera system that is capable of performing both a PET and CT scan at the same time. A CT scan is an anatomical imaging test and, for this research study, will mainly be used to localize the area of 18FDG accumulation recorded by the PET scan. The examination will take approximately one hour.