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
In pulmonary embolism, findings in perfusion scan isa) Perfusion segmental defectb) Perfusion defect with normal lung scan & radiographyc) Tenting of diaphragmd) Normal chest scan 
Select and explain. 
A. abd, B. bcd, C. abc, D. ab
A: abd
Answer: A: abd 
Explanation: At least 2% of patients with PE have normal V/Q scan and 4% of patients with normal V/Q scan have pulmonary embolism.
41% 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.