The diagnosis of pulmonary embolus is difficult despite advances in our understanding of the pathophysiology. The clinical diagnosis of pulmonary embolus is unreliable.
Most patients present with dyspnea.
However, the signs and symptoms of pulmonary embolus are non-specific. Computed tomography provides information that is not available from the radiograph or angiography. The typical appearance of pulmonary infarction on CT can suggest the diagnosis when it was not previously considered. A negative test essentially rules out the diagnosis. A high probability scan makes the diagnosis highly likely but is less specific when patients have suffered previous emboli.