This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
[{'content': 'True about features of cholecystitis on USG – a) Thick fibrosed gallbladder wallb) Stone impacted at neck of gall bladderc) Perigallbladder halod) Increased vascularity \nSelect and explain. \nA. abc, B. bc, C. acd, D. bcd', 'role': 'user'}, {'content': "Answer: A \nExplanation: USG findings of acute cholecystitis\xa0\n\nGallbladder wall thickening\nPericholecyst fluid producing circumferential halo of low echogenicity around gallbladder\nEchogenic bile sludge may completely fill the gallbladder lumen and gives appearance of adjacent liver (hepatization of bile)\nGall stone :- May be impacted in the neck or cystic duct\nSonographic murphy's sign (Tenderness on pressing the transducer onto the gallbladder)", 'role': 'assistant'}]