Pulmonary ventilation/perfusion scan

Pulmonary Ventilation/Perfusion Scan

A pulmonary ventilation/perfusion scan is a test used to evaluate blood flow and oxygen levels in the lungs. It uses a radioactive tracer called technetium-99m to measure the amount of air and blood flow in the lungs. It can be used to diagnose pulmonary embolism (a potentially life-threatening condition where a blood clot blocks an artery in the lungs) or to assess the amount of lung damage caused by other disorders such as asthma or COPD. The test is also known as a V/Q scan.

Preparation

You may need to wear a hospital gown or loose-fitting clothing to the hospital for the procedure. Additionally, you will be asked to refrain from eating or drinking anything for several hours prior to your scan.

Procedure

During the procedure, you will be asked to lie down on a table. A radioactive tracer will be injected into your arm and then you will be asked to blow into a tube to help the tracer move through your lungs. The tracer will collect in the lungs and then a special camera will detect the tracer and create a detailed image of the lung structure and function. The procedure usually takes about 30 minutes.

Types of Scans

• Ventilation Scan – This scan measures how well air is moving in and out of your lungs.
• Perfusion Scan – This scan measures the amount of blood flow to the lungs.

Risks

The nuclear radiopharmaceuticals used in pulmonary V/Q scanning are generally safe. Some people may experience slight discomfort or chest pain when the tracer is injected. Additionally, some people may have allergies to the radioactive tracer.

Why Get the Test?

The primary purpose of a pulmonary V/Q scan is to diagnose pulmonary embolism. This condition occurs when a blood clot gets lodged in an artery in the lungs and prevents enough oxygen from getting to the lungs. The scan can also be used to diagnose other conditions such as asthma, COPD, or pneumothorax.

When to Get the Test

Your doctor may recommend a V/Q scan if you are experiencing any of the following symptoms: shortness of breath, chest pain, coughing, wheezing, or swelling in your legs or arms. If you have risk factors for developing a blood clot or pulmonary embolism, such as a surgery or recent long-distance travel, your doctor may order a V/Q scan to rule out the condition.