Computed tomography pulmonary angiography as a single imaging test to rule out pulmonary embolism

The aim is to review the evidence on the diagnostic value of computed tomography pulmonary angiography (CTPA) as a single test to rule out acute pulmonary embolism by focussing on the most recent literature and potential alternative and additional imaging modalities or diagnostic strategies.

Clinical outcome studies have demonstrated that, using algorithms with sequential diagnostic tests, pulmonary embolism can be safely ruled out in patients with a clinical probability indicating pulmonary embolism to be unlikely and a normal D-dimer test result. This obviates the need for additional radiological imaging tests in around one-third of patients. CTPA has been shown to have a high sensitivity and specificity for the diagnosis of pulmonary embolism. Several emerging tests with potential diagnostic or other advantages over CTPA need further validation before they can be implemented in routine clinical care.

CTPA is the imaging test of first choice. The presence or absence of pulmonary embolism can be determined with sufficient certainty without the need for additional imaging tests after a negative CTPA. Compression ultrasonography and ventilation-perfusion scintigraphy is reserved for patients with concomitant symptomatic deep vein thrombosis or a stringent contraindication for CTPA, respectively. Currently, magnetic resonance pulmonary angiography is not a suitable alternative for CTPA.