Test Details & Preparation
A lung ventilation/perfusion scan is a series of two scans that measure how well air and blood are able to flow through your lungs (ventilation scan), as well as the blood supply through the lungs (perfusion scan). The scans are either performed together or one after the other, but are often discussed as one scan: the lung ventilation/perfusion scan.
During a lung ventilation/perfusion scan, a radioactive dye is injected into your veins. This dye will show up on a special type of scanner, and will give your doctor information about how well your lungs are working. The dye will gather at areas of abnormal blood flow, which may indicate a blockage in the lung artery. This test may also be called a V/Q scan or a radionuclide lung scan.
A lung ventilation/perfusion scan is used most frequently to screen for lung embolus, which is also known as a blood clot in the lungs. Symptoms of lung embolus include rapid heart rate, trouble breathing, decreased oxygen saturation levels, and chest pain.
This scan may also be used to screen for other lung conditions, or to test the lung function in individuals with lung disease. The lung ventilation/perfusion scan may be used to screen for or test lung function in lung infections or inflammation, such as bronchitis, pneumonia, or pneumonitis chronic lung diseases, such as chronic obstructive lung disease (COPD) or emphysema lung effusion, which occurs when fluid collects around the lungs lung artery narrowing airway obstruction, which can be caused by a tumour.
There is a low risk associated with a lung ventilation/perfusion scan. However, problems can arise due to the radioactive substances and the insertion of the intravenous (IV) line. Possible risks include excessive bleeding at the IV site infection at the IV site and rare allergic reaction to the radioactive dye.