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
Best investigation for acute cholecystitis is 
Select and explain. 
A. ERCP, B. Oral cholecystography (OCG), C. HIDA scan, D. IV cholangiography
C: HIDA scan
Answer: C: HIDA scan 
Explanation: C i.e. HIDA Scan HIDA Scan & PIPIDA are best test to rule out acute cholecystitisQ with.--400% negative predictive value. It can be pseudo positive in chronic malnutrition, & Parenteral nutrition & alcoholic liver disease.