This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nuclear medicine, Subject name: Radiology
[{'content': 'Hot rim sign on hepatobiliary scintigraphy (Tc99m-HIDA ) is seen in ? \nSelect and explain. \nA. Chronic cholecystitis, B. Biliary Atresia, C. Gangrenous Cholecystitis, D. Porcelain GallBladder', 'role': 'user'}, {'content': 'Answer: C \nExplanation: * Increased Pericholecystic hepatic band of radio tracer activity called Rim sign. * A rim of increased hepatic activity directly adjacent to the gallbladder fossa in association with non visualization of the gall bladder is a specific sign of acute cholecystitis paicularly associated with gangrene and perforation . Below CT Image Shows Emphysematous Cholecystitis with Necrosis and Air within the wal of GB.It is surgical Emergency with high risk of GB perforation and moality.', 'role': 'assistant'}]