HIDA Rim Sign Auntminnie!

What is the HIDA rim sign?
In other words, the HIDA rim sign is pericholecystic hepatic activity sign - it represents late stage of acute cholecystitis where uptake is seen in the region of the superior aspect of the gallbladder along the fossa / liver. The HIDA rim sign is highly specific with high predictive value for complicated acute cholecystitis and is a harbinger of hemorrhage, necrosis of wall, ulceration, necrosis, fibrous exudation, perforation, empyema, or gangrene.