Pulmonary ventilation/perfusion scan

Alternative names:

scan - lung ventilation/perfusion; V/Q scan

How the test is performed:

This is actually 2 tests that may be performed separately or together.

The perfusion scan is performed by injecting radioactive albumin (99m Tc macroaggregated albumin) into a vein. You are immediately placed on a movable table that is positioned under the arm of the scanner. Your lungs are scanned to detect the location of the radioactive particles as blood flows through the lungs.

The ventilation scan is performed by scanning the lungs while having the person inhale radioactive gas (air mixed with 133 xenon or 99m Tc DTPA aerosol). A mask is placed over the nose and mouth and you are asked to breathe the gas while sitting or lying on the table beneath the arm of the scanner.

How to prepare for the test:

No diets, medications, or fasting are necessary before the test.
A chest X-ray may be performed prior to or following a ventilation and perfusion scan.

You must sign a consent form. You are asked to wear a hospital gown or comfortable clothing without metal fasteners. Remove jewelry and dentures before the scan.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

• infant test or procedure preparation (birth to 1 year)
• toddler test or procedure preparation (1 to 3 years)
• preschooler test or procedure preparation (3 to 6 years)
• schoolage test or procedure preparation (6 to 12 years)
• adolescent test or procedure preparation (12 to 18 years)

How the test will feel:

The table may be hard or cold. There may be a sharp prick during injection of material into the vein for the perfusion portion of the scan. The mask used during the ventilation scan may give some persons a claustrophobic feeling. You must lie still during scanning.

You will not feel the radioisotope.

Why the test is performed:

The ventilation scan is used to evaluate the ability to aerate all portions of the lungs. The perfusion scan measures the supply of blood through the lungs.

A ventilation and perfusion scan is performed to detect pulmonary embolus. It is also used to evaluate lung function in people with pulmonary disease such as COPD, to locate and evaluate growths before and after treatment, and to detect conditions such as lung infections and lung collapse. It may be used to evaluate the extent of burn inhalation injury.