This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
Features suggestive of Acute cholecystitis on CT abdomen are all Except 
Select and explain. 
A. Pericholecystic fluid, B. Presence of gallstones, C. Contratcted gall bladder, D. Air in the gallbladder wall
C: Contratcted gall bladder
Answer: C: Contratcted gall bladder 
Explanation: Diagnostic criteria for acute cholecystitis on CT includemajor criteriagallstonesthickened gallbladder wallpericholecystic fluid collectionssubserosal oedemaminor criteriagallbladder distentionsludgeContraction of the gallbladder is sen in cholelithiasis, not acute cholecystitis.