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.