Exercise Cardiac Perfusion Imaging

Exercise cardiac perfusion imaging is a medical test that uses a radioactive substance, known as a tracer, to assess the flow of blood to the heart muscle. It produces images of the heart muscle during periods of exercise.

The test helps doctors diagnose coronary heart disease, which is caused by narrowed or blocked coronary arteries.

During an exercise cardiac perfusion test, a small amount of tracer is injected into a vein in your arm, once while you exercise, and once at rest.

The tracer travels in the bloodstream and is picked up by the heart muscle. Areas of the heart muscle that have a good supply of blood pick up the tracer right away. Areas that do not have a good supply pick up the tracer very slowly or not at all.

The tracer gives off a small amount of radiation that is detected with a scanning camera. A computer processes the information and produces images that show how radioactivity is distributed in the heart.

If an area of the heart receives less blood than the rest of the heart (because of a narrowed or blocked artery), it will pick up less radioactivity and will show up as a lighter area, called a "defect."

One set of images is taken after you exercise, another set is taken while you are at rest. The images allow doctors to compare how much blood flows to the heart muscle during stress and at rest.

This test can take from two to four hours. If you are an outpatient, you may be allowed to leave the test area between the two parts of the test. Or, you may be asked to return the next day for more imaging.