Radionuclide imaging of acute pulmonary embolism.

Pulmonary embolism (PE) is a potentially fatal condition for which treatment is highly effective. The diagnosis of PE can be challenging and often requires diagnostic imaging. For many years, chest radiographs and ventilation-perfusion (V/Q) scintigraphy have been the primary imaging modalities used in the evaluation of patients with suspected acute PE. The combination of clinical assessment, plus results of V/Q scintigraphy and a noninvasive venous study of the lower extremities can provide clinicians with the information needed to direct treatment in the majority of patients with suspected PE. More recently, advances in computerized tomography (CT) angiography have allowed for the direct visualization of PE, and this technique has emerged as an important diagnostic test in the evaluation of patients with suspected PE. Proponents suggest that CT angiography should be used as the first line imaging test in patients with suspected PE. Others suggest that V/Q scanning should remain as the first line diagnostic imaging test and that CT angiography should be used in patient's in whom the diagnosis remains uncertain. The combination of CT angiography and CT venography has the potential to provide a single comprehensive study of patients with suspected venous thromboembolism.