pic-echo

Procedure Overview

What is a stress myocardial perfusion scan?

Myocardial perfusion imaging (MPI) is a non-invasive imaging test that shows how well blood flows through your heart muscle. It can show areas of the heart muscle that aren’t getting enough blood flow (ischemia) and can show heart damage from old heart attacks. This is called a nuclear stress test.  It can also show how well the heart muscle is pumping (ejection fraction).

 

There are two types of stress myocardial perfusion scans. Treadmill exercise stress for people who are able to walk. The second is a chemical stress test in people who are unable to walk or reach their individual target heart rate.

 

Reasons for the procedure
MPI is used in patients with chest discomfort to see if the discomfort comes from lack of blood flow to the heart muscle due to narrowed or blocked heart arteries (angina).  Myocardial perfusion imaging doesn’t show the heart arteries themselves, but can tell your physician with good certainty how many heart arteries are blocked, if any.  MPI can also show if you’ve previously had a heart attack.

 

For example, depending on your circumstances, if you have chest pain and an abnormal MPI study, the next step may be performing acoronary angiogram.  However, if the MPI study is normal, your physician now can look into other causes of chest pain that aren’t heart-related.

An MPI test shows how well blood flows through your heart muscle. If the test shows a lack of blood flow during exercise or stress, but is normal at rest, it could mean that an artery that carries blood to your heart is narrowed or blocked. If the test shows a lack of blood flow to a portion of the heart muscle during exercise or stress and at rest, it could mean that your heart muscle has scarring, possibly from a previousheart attack.

 

Risks to the procedure
MPI tests are generally safe for most people. MPI studies expose you to a low dose of X-rays. Experts disagree if X-rays at such low doses can cause cancer, but the possibility exists that no dose of X-rays, however low, is completely safe.  Don’t take the test if your risk for a heart attack is low, or if there is no other reason (chest discomfort) to think that you have heart problems. If you’re pregnant or think you might be pregnant, or if you’re a nursing mother, tell us before you have this test because it can harm your baby.

 

Before the procedure

  1. If you are scheduled from 7:30 am-8:30 am, do not have anything to eat or drink after midnight the night before.
  2. If you are scheduled from 10:30 am- 11:30 am, do not have anything to eat or drink after 6 am the day of the appointment. You may have a light breakfast with no milk.
  3. If you are scheduled from 12:30 pm- 1:30pm, do not have anything to eat after 8am the day of the appointment. You many have a light meal with no milk.
  4. No caffeine or nicotine after midnight the night before for ALL test times.
  5. Wear comfortable clothing and shoes.
  6. Bring a list of all medications, allergies, and insurance information.
  7. No lotion or powder on your chest.
  8. Take your normal medications, unless medical personnel tells you otherwise.
  9. ALL DIABETICS: You may have juice and toast and ½ your insulin and/or pills 2 hours prior to testing.
  10. Duration of time: approximately 2-3 hours.

 

During the procedure
Specially trained technicians usually perform the test in a hospital or clinic with special equipment.

  1. The technician places small metal disks (electrodes) on your chest, arms and legs. The disks have wires that hook up to a machine to record your electrocardiogram (ECG). The ECG keeps track of your heartbeat during your test and is used to tell the camera when to take a picture.
  2. You’ll wear a cuff around your arm to keep track of your blood pressure.
  3. The technician will put an intravenous line (IV) in your arm.
  4. You’ll exercise on either a treadmill or exercise bicycle
  5. If you cannot exercise, your IV line will be connected to a bag that has a medicine to increase the blood flow to your heart, similar to when you exercise, or make your heart go faster. This is called a chemical or pharmacologic stress test. These medicines may include adenosine, dipyridamole (Persantine) or dobutamine.
  6. When you reach your peak activity level, you’ll stop and receive a small amount of radioactive material (tracer) through the IV line.
  7. You’ll lie still on a table for 10- 30 minutes while the gamma camera takes pictures of your heart. Several scans are done during that time to provide pictures of thin slices of your entire heart from all angles. It’s very important to hold completely still with your arms above your head while the pictures are being taken.
  8. During the resting part of the test, you’ll receive more tracer and another set of pictures will be taken. This set of images will be compared to the images taken after exercise or stress.
  9. Some forms of the test do not use stress or exercise, but take 2 sets of rest images with 2 different tracers.

The test takes between 3 and 4 hours. Some labs may do the resting part of the test first, or do the resting and exercise tests on different days.

 

After the procedure
You can usually go back to your normal activities right away.

  1. Drink plenty of water to flush the radioactive material from your body.
  2. You will be notified of your results and treatment plan by your doctor