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: Medicine
[{'content': 'The most definitive method of diagnosing pulmonary embolism is : \nSelect and explain. \nA. Pulmonary aeriography, B. Radioisotope perfusion pulmonary scintigraphy, C. EKG, D. Venography', 'role': 'user'}, {'content': "Answer: A \nExplanation: Answer is A (Pulmonary aeriography): `Selective pulmonary angiography is the most specific examination available for establishing the definitive diagnosis of PE.'-Harriosn 16th/1563 Most definitive investigation :Pulmonary angiography is an invasive procedure, and it is the most definitive procedure. It is however ceainly not the initial investigation of choice. The initial investigation of choice in a case of suspected pulmonary embolism is either a lung ventilation perfusion scan or a CT of the chest with intravenous contrast. `CT scanning of the chest with intravenous contrast is the principal imaging test for diagnosis of PE.' - Harrison `Lung scanning (V/Q scan) is now a second line diagnostic test for PE' Most definitive / specific test for PE Q Best initial imaging test for diagnosis of PEdeg Pulmonary angiographyQ CT scan with intravenous contrast Q (Preferred choice, against a lung V-Q scan)", 'role': 'assistant'}]