A 55 year old man who has been on bed rest for the past 10 days, complain of breathlessness and chest pain. The chest X-ray is normal. The next step in the investigation should be –
This patient has a high clinical likelihood of pulmonary embolism because clinical assessment score is more than 4:-


Signs & symptoms of PE (Breathlessness & chest pain) → score 3.0
Immobilization (bed rest) > 3 days → score 1.5


So, the total score is 4.5. Therefore, imaging test should be done. CT contrast is the imaging test of choice.
Lung ventilation – perfusion scan
Pulmonary arteriography
Pulmonary venous wedge angiography
Echocardiography