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': 'The investigation of choice for Renal scarring defect in infected kidney is: \nSelect and explain. \nA. DMSA scan, B. DTPA, C. DEXA, D. MCU', 'role': 'user'}, {'content': 'Answer: A \nExplanation: DMSA (99mTc-dimerruptosuccinic acid) scan: the most sensitive test for detection of acute pyelonephritis and renal scarring. It is best delayed for 4-6 months after acute infection to distinguish acute parenchymal defects from renal scars. Ref: Clinical Pediatric Urology By A. Barry Belman, Lowell R. King, Stephen Alan Kramer, 2002, Page 287', 'role': 'assistant'}]