What Does a Lung Ventilation/Perfusion Scan Show?

A lung ventilation/perfusion (VQ) scan shows how well air and blood are flowing through your lungs. Normal results will show full air and blood flow to all parts of your lungs.

If air flow is normal but blood flow isn’t, you may have a pulmonary embolism (PE). PE occurs when a blood clot travels to the lungs and blocks blood flow.

The results of the scan will show whether you’re at high, medium, or low risk for PE. However, a VQ scan alone won’t confirm whether you have PE. A scan showing low blood flow in spots may reflect other lung problems, such as lung damage from COPD (chronic obstructive pulmonary disease).

Your doctor will use the VQ scan results along with results from a physical exam, chest x ray, and other tests to make a diagnosis.