The value of lung scintigraphy in the diagnosis of pulmonary embolism

The role of lung scintigraphy in the diagnostic management of patients with clinically suspected pulmonary embolism is reviewed. Evidence is provided that a normal perfusion scan excludes clinically relevant pulmonary embolism, and that a high probability lung scan, defined as a segmental perfusion defect with locally normal ventilation, sufficiently confirms the presence of pulmonary embolism in the majority of these patients. Furthermore, this review assesses the possibility of non-invasive tests for the diagnosis or exclusion of venous thromboembolic disease as a means of avoiding pulmonary angiography in patients with lung scan outcomes that are neither normal nor high probability.