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Who Needs a Lung Ventilation/Perfusion Scan?

You may need a lung ventilation/perfusion (VQ) scan if you have signs or symptoms of a pulmonary embolism (PE). A PE is a sudden blockage in a lung artery. A blood clot usually causes the blockage.

Signs and symptoms of a PE include chest pain, trouble breathing, rapid breathing, coughing, and coughing up blood. An irregular heartbeat called an arrhythmia (ah-RITH-me-ah) also may suggest a PE.

Some blood clots that can cause a PE travel to the lungs from veins deep in the legs. This can cause pain and swelling in the affected limb.

Doctors use VQ scans to help find out whether a PE is causing these signs and symptoms. A VQ scan alone, however, won't confirm whether you have a PE. Your doctor also will consider other factors when making a diagnosis.

Doctors also use VQ scans to detect poor blood flow in the lungs' blood vessels, air trapping or uneven air distribution, and to examine the lungs before some types of surgery.

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Lung Ventilation/Perfusion Scan Clinical Trials

Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Lung Ventilation/Perfusion Scan, visit

July 25, 2014 Last Updated Icon

The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.