Myocardial Perfusion Imaging (MPI)
Myocardial Perfusion Imaging (MPI) is a non-invasive way to detect and assess coronary artery disease. It can help your doctor determine how severe your coronary artery disease might be and how much of your heart is affected.
The test uses a radioactive material (a radiopharmaceutical) which is usually injected into an arm vein and allows us to obtain images of your heart. A gamma camera is used to examine how well the radiopharmaceutical has been taken up by your heart muscle.
This exam is performed over two days:
- On Day One, a radiopharmaceutical is injected into your arm vein while at rest and images of your heart are taken.
- On Day Two, a radiopharmaceutical is injected into your arm vein, through an intravenous line (IV), while you’re exercising, and images of your heart are taken shortly after. If you’re unable to exercise on the treadmill, you can be given a medication (through your IV) that dilates your heart’s arteries to “mimic” a stress condition.
HOW DO I PREPARE FOR MY EXAM?
- Please let your technologist know if you are claustrophobic prior to the start of the exam.
- On Day One, arrive 15 minutes before your appointment to fill out some paperwork.
- For both days, please do not wear perfumes, colognes or other scented products.
- On Day Two, wear comfortable clothing and appropriate shoes for the treadmill. Wear a short-sleeved shirt with plastic buttons or a big T-shirt so we can easily place the electrodes on your chest. Women will be asked to remove their bra for the duration of the test. Change rooms are available.
- Bring all current medications with you.
- Continue taking all medications unless otherwise instructed by your physician. In some cases, certain heart drugs, such as Beta Blockers and Calcium-Channel Blockers (see the list below), should be stopped for 48 hours before and during the day of the stress test. Please check with your doctor for more information.
- Acebutolol (Monitan, Rhotral, Sectral)
- Atenolol (Tenormin)
- Bisoprolol (Monocor)
- Carvedilol (Coreg)
- Labetolol (Normodyne)
- Metoprolol (Lopressor, Toprol XL, Lopressor SR)
- Nadolol (Corgard)
- Oxprenolol (Trasicor)
- Pindolol (Visken)
- Propranolol (Inderal)
- Sotalol (Sotacor)
- Timolol (Blocadren)
- Diltiazam (Cardizem CD/SR)
- Felodipine (Plendil, Renedil)
- Verapamil (Isoptin Chronovera)
TWO DAYS BEFORE THE EXAM
- Do not have any barium exam studies done within two days before the MPI study, as they can alter the results of the exam.
- If your doctor has said that certain heart drugs (in the list above) should be stopped, please stop taking them for 48 hours before and during the day of the stress test.
ONE DAY BEFORE THE EXAM
- Avoid all foods or beverages that contain caffeine (e.g., coffee, tea, chocolate, decaf coffee, decaf tea, pop) in the 24 hours before your test.
- Avoid medications that have caffeine (e.g., Tylenol #3, Anacin, Excedrin, No-Doz, Darvon, Caffregot, Fiorinal, etc.).
FOUR HOURS BEFORE YOUR EXAM
- Don’t eat or drink anything before your exam.
- You may take small sips of water with prescribed medications.
- Do NOT smoke.
- SPECIAL NOTE: If you take medication to manage your blood sugar and can’t fast for four hours, please call your doctor for specific instructions. You may fast for two hours, eat a small meal and take your diabetes medication as prescribed prior to the two hours. Remember to bring your glucose monitor to the exam and if you think your blood sugar is low, let the technologist know right away.
WHAT HAPPENS DURING MY EXAM?
DAY ONE: Rest Study
- You will fill out your paperwork. This will take approximately 15 minutes. (Please bring a translator with you if you need assistance filling out your forms).
- The complete procedure will be explained to you by the technologist.
- We with inject a radiopharmaceutical into an arm vein. This material will be taken up by your heart muscle.
- Images of your heart will be taken 45 minutes later. These images take approximately 15 minutes to complete.
- For the images, you will be positioned on the imaging bed, with your arms above your head.
- During your wait, you will be asked to eat something fatty (this helps to contract the gallbladder and gives us better images of the heart). You are also able to drink a caffeine-free beverage (e.g. water, white milk and juice).
DAY TWO: Stress Study
- When you arrive in the morning, we’ll insert an intravenous (IV) line into your arm and attach electrodes to your chest. They will be connected to an electrocardiograph monitor (EKG) that charts your heart’s electrical activity during the test.
- A physician specialising in internal medicine will consult with you prior to the start of the test. If you have any medical questions concerning your test, this is an ideal time to discuss them.
- Before you start the exercise portion of the study, the technologist will take a resting EKG reading, measuring your resting heart rate. They will also take your blood pressure.
- We will then start you walking on the treadmill. It will start out very slow, then speed and incline will gradually increase, every three minutes. The majority of the program is a walking pace. Some patients may end up jogging.
- Your blood pressure will be taken a number of times while you are walking on the treadmill.
- The technologist will ask you how you are feeling throughout the test.
- Please tell your technologist if you feel short of breath, dizzy, lightheaded or experience chest, arm or jaw pain or discomfort, or if you have any other unusual symptoms.
- We will stop the test if you become too tired, experience chest pain or when the technologist has enough information.
- If you are able to exercise on a treadmill, the radiopharmaceutical will be injected into the IV when you are near the peak of your exercise. You will then be required to walk an additional minute after the injection of the radiopharmaceutical.
- Most patients are on the treadmill for at least 5–10 minutes.
- If you are unable to walk on a treadmill, an alternative is available. A medicine called Persantine (or Dipyridamole) can be injected through the IV. This opens your heart’s blood vessels similar to exercise and allows us to “chemically stress” your heart. Our internal medicine physician will decide whether or not this is the preferred way of performing your exam.
- We will remove your IV and monitor you for about five minutes after you get off the treadmill to ensure that your heart rate and blood pressure are stable.
- You will then be required to eat and drink. Please bring food with you; your caffeine restrictions are lifted at this time.
- Approximately 25 minutes post-injection, we will take some images which will take approximately 15 minutes.
The radiopharmaceutical is excreted from the body through your urine. Keeping hydrated and voiding frequently will help eliminate it from your body.
WHEN WILL I GET MY RESULTS?
Both your rest and stress study will be processed and then reviewed by a nuclear medicine radiologist. Your referring practitioner will receive a copy of the following:
- Your rest and stress imaging report.
- Your specialist consultation report.
- Your treadmill report.
We will do our best to get the results to your doctor by the next business day.
HOW MUCH WILL IT COST?
This exam is covered under your Alberta Health Care Plan. It is not currently offered at our Saskatchewan clinic.
In certain circumstances (e.g., scuba diving or pilot’s license), you may be required to pay for the exam.