Clinical and radiological diagnosis of pulmonary thromboembolism

Pulmonary thromboembolism has poorly specific clinical symptomatology, which increases the diagnostic suspicion, multiplying the number of patients who will need to undergo imaging tests to confirm the diagnosis. In recent years, pulmonary angiography using multidetector scanners (CT angiography) has been the most widely used imaging test due to its availability and accuracy, which exceeds that of lung ventilation-perfusion (V/Q) scintigraphy. However, CT angiography is not without risks and is also expensive. Its use should therefore be restricting without reducing the diagnostic efficacy, given its enormous prognostic importance and implication. We therefore need to base our approach on previously validated strategies that, taking into account the clinical probability and using highly sensitive diagnostic tests such as D-dimer, will enable us to exclude many patients from undergoing this imaging test. In this article, we review the diagnostic techniques and strategies that are applied for diagnosing pulmonary thromboembolism in hemodynamically stable and unstable outpatients, hospitalised patients, patients with a history of venous thromboembolism and pregnant women.