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': 'In pulmonary embolism, findings in perfusion scan isa) Perfusion segmental defectb) Perfusion defect with normal lung scan & radiographyc) Tenting of diaphragmd) Normal chest scan \nSelect and explain. \nA. abd, B. bcd, C. abc, D. ab', 'role': 'user'}, {'content': 'Answer: A \nExplanation: At least 2% of patients with PE have normal V/Q scan and 4% of patients with normal V/Q scan have pulmonary embolism.\n41% of patients with PE have high probability scan which includes 2 or more segmental perfusion defects with normal chest radiograph and normal lung ventilation scan.', 'role': 'assistant'}]