The most definitive method of diagnosing pulmonary embolism is -

Ans. is 'a' i.e., Pulmonary arteriography Selective pulmonary angiography is the most specific examination available for establishing the definitive diagnosis of pulmonary embolism and it can detect emboli as small as 1-2 mm. Its the gold standard test for diagnosing pulmonary embolism. So, Pulmonary angiography is the most reliable test for diagnosis but it is invasive, time consuming, and expensiveChest CT scanning is replacing diagnostic pulmonary angiography because it is less invasive and less expensive and has adequate specificity (90% comparable to that of pulmonary angiography).Now a days Angiography is done in only following condition.Patients with technically inadequate CT scansScans performed on older machines that cannot image fourth and fifth order pulmonary arteries.Patients who have to undergo t/t interventions such as catheter embolectomy or catheter directed thrombolysis.Radionucleotid ventilation and perfusion lung imaging VO scan has been replaced by chest CT as the initial imaging test for suspected pulmonary embolism.VQ scanning can be used in situations where CT scanning is not feasible.