A pulmonary perfusion scan looks at the blood flow to the lung tissue. It is used most often to diagnose a blood clot in the lung, known as a pulmonary embolus.
The healthcare provider may order a pulmonary perfusion scan in the following circumstances:
For the scan, a person is often asked to sit upright. If a person is unable to sit, he or she can lie flat on a table. A radioactive substance known as Tc-99m macroaggregated albumin will be injected into a vein in the arm. The substance gives off gamma rays from within the body. These rays are detected by a "gamma camera" that is positioned over the chest.
A computer then generates pictures that can be interpreted by a radiologist. The lungs will be scanned in multiple positions (usually six). The exam takes approximately 45 minutes. Usually, a second test called a pulmonary ventilation scan will follow the perfusion scan.
The individual will undress from the waist up and put on an exam gown. All jewelry and metal objects will be removed.
A normal test shows that the blood flow to the lung is normal. An abnormal test result often indicates a problem with blood flow to the lungs caused by a pulmonary embolus.
Author:James Compton, MD
Date Written:
Editor:Crist, Gayle P., MS, BA
Edit Date:05/21/01
Reviewer:Adam Brochert, MD
Date Reviewed:05/22/01