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Ency. home > Test > P > Pulmonary ventilation/perfusion scan

Pulmonary ventilation/perfusion scan   

Overview | Risks | Results

Alternative names:

V/Q scan; Ventilation/perfusion scan; Lung ventilation/perfusion scan

Definition:

A nuclear scan test using inhaled and injected radioactive material (radioisotopes) to measure breathing (ventilation) and circulation (perfusion) in all areas of the lungs.

How the Test is Performed

Two tests that may be performed separately or together.

The perfusion scan is performed by injecting radioactive albumin (99m Tc macroaggregated albumin) into a vein. The patient is immediately placed on a movable table that is positioned under the arm of the scanner. The patient's 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 is usually performed prior to or following a ventilation and perfusion scan.

The patient usually signs a consent form and is asked to wear a hospital gown or comfortable clothing without metal fasteners.


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:

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. The patient must lie still during scanning.

The radioisotope injection usually does not cause a specific feeling.

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 most often performed to detect pulmonary embolus. It is also used to evaluate lung function in people with advanced  pulmonary disease such as COPD.  It is also used to detect the presence of shunts (abnormal circulation) in the pulmonary blood vessels.

Ency. home > Test > P > Pulmonary ventilation/perfusion scan

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