The Treadmill Stress Test with Myocardial Perfusion Imaging (MPI) is an exercise based heart test that can be done in conjunction with nuclear imaging to increase the sensitivity (accuracy) of the test. This stress test uses a short-lived radioactive material, which along with computer imaging will help highlight any severely diseased blood vessels that may be causing diminished blood flow to your heart.
The additional imaging added to a stress test is particularly beneficial for women undergoing exercise tests, as women are more likely to have EKG abnormalities that are benign. Nuclear pictures will better help the physician determine whether changes on your EKG are stemming from heart disease, or a heart-related cause of symptoms, such as shortness of breath or chest or upper back pain.
Test Procedure
- An intravenous (IV) line will be started to allow the technician to inject Cardiolite (the radioactive material). Cardiolite is a radioactive tracer used for computer imaging of your heart that will be taken later. Cardiolite is not a drug or dye
and causes no known side effects or symptoms. After about 45 - 60 minutes, you will be set up under the imaging camera and asked to lie on your back with your arms over your head for 15 - 20 minutes.
- The second part of your test is the exercise portion. An exercise technician will place electrodes (small adhesive patches) on your chest, wrists and ankles. Lead wires will then be connected to the electrodes.
- You will lie down on your back for a few minutes while electrocardiograms (EKG) and a blood pressure are obtained. You will have an additional EKG and blood pressure measurement taken while standing. These initial steps are taken to ensure there are
no significant abnormalities that would prevent your test from being done.
- You will be asked to walk on a treadmill for approximately 5 - 15 minutes. The test begins slowly and increases gradually in speed and incline every two to three minutes. During this time, your heart rate, blood pressure and EKG will be monitored.
- Your responsibility is to exercise to the best of your ability (it is not an absolute maximum effort but should be a level higher than you would typically perform at home). When you are near the desired heart rate range (pre-determined by age), the
second Cardiolite dose will be given through your IV.
- You should inform the test supervisor of any developing symptoms (leg pain, chest pain, dizziness, lightheadedness, shortness of breath). If there are any abnormal responses the test can be stopped.
- A minimum six-minute recovery period is then done as a cool-down with continued heart rate, blood pressure and EKG monitoring. As soon as these measurements are close to your initial or resting values, you will be disconnected from the monitor.
- Approximately 30 - 60 minutes after the exercise portion of your test, you will be take to the Nuclear Medicine department for a second series of pictures of your heart. You will lie on your back with your arms over your head for 15 - 20 minutes.
You may also be asked to lie on your stomach for an additional 15 - 20 minutes for a second set of pictures.
- A cardiologist and a nuclear medicine physician will review the test and interpret it for your follow-up visit or for forwarding to your referring physician.
Allow approximately 3 - 4 hours for your procedure as there are significant wait times required between each step of the test. The wait time is necessary to ensure good images under the camera.