Scan measures how much blood in your heart muscle
Your doctor may prescribe a myocardial perfusion scan if you’re having symptoms such as chest pain (angina), or to assess damaged areas and blood flow to your heart after a heart attack. Myocardial perfusion scans or myocardial perfusion imaging (MPI), also referred to as cardiac nuclear imaging, can also help diagnose coronary artery disease (CAD) and help guide treatment decisions for CAD. The scan measures the amount of blood in your heart muscle while you are resting and also while you are exercising (“stress”).
How myocardial perfusion scan is performed
A myocardial perfusion scan is done in two parts, one at rest and one during exercise. The scans may be performed on the same day or you may be asked to come back the next day for the second part of the test. The at-rest scan is often done first.
You will first be given special medicine through a vein in your arm. The medicine has a radioactive “tracer” that is absorbed by areas of the heart that have good blood flow, but not absorbed in areas with poor flow or damage. After the tracer has moved through the blood to the heart, the radiologist will take photos with a large camera that is positioned over your body. The tracer material that is left behind in your heart can be seen in the photos and will allow the radiologist to interpret the results.
For the stress or exercise portion of the scan, patches of electrodes will be placed on your chest and you will be monitored while walking on a treadmill or using a stationary bike. After you have reached a maximum point of exertion (based on your heart rate and age), the doctor will inject the tracer into your IV line and you will continue to exercise for a bit longer. You will then be asked to lie down on the scanning table so the radiologist can take photos of your heart in its “stressed” state. The radiologist will later compare the results of your resting scan vs. your stress scan. These results will be reported to your doctor who will then go over the results and discuss next steps with you.