<prompt> Hot rim sign on hepatobiliary scintigraphy Tc99m-HIDA is seen in ?Chronic cholecystitisBiliary AtresiaGangrenous CholecystitisPorcelain GallBladder  <response>: 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. 