What is it?

The purpose of a myocardial perfusion scan is to assess the flow of blood through the heart and the heart’s pumping function, during exercise as well as when at rest. To this end, the test is conducted on two separate days (once after exercise, and once during rest). During the test, an isotope (99 mTc-MIBI) is injected through the IV drip. This is a radioactive substance that is absorbed by the heart muscle cells and produces a small amount of radiation. This radiation can be observed with a gamma camera at the Nuclear Medicine Department. A comparison of the two images (after exercise versus during rest) gives the cardiologist insight into the blood flow through the heart. An abnormality in the blood flow through the heart may indicate a constriction of the coronary arteries.

What is the process?

Preparation for the test

  • The procedure may take place on a Monday, Wednesday or Friday. You will be booked in for two sessions.
  • Fasting is necessary for both days .
    Type of food:Example:Allowed until at the latest:
    Normal mealmidnight before the surgery or examination
    Light meale.g. a sandwich or toast with jam. Deep-fried/fatty foods or meat are not includedsix hours prior to the procedure or examination
    Dairy productsMilk, bottle-feeding for a child, yoghurt...six hours prior to the procedure or examination
    Breastfeedingfour hours prior to the procedure or examination
    DrinksAs wished: water, sugar water, sports drinks, clear fruit juices without pulp (apple juice, grape juice)

    Maximum
    a cup: clear tea and coffee without milk
    .
    Recommended: continue to drink clear beverages up to two hours before the procedure or examination
    Up to six hours before the procedure: fizzy drinks

    (Exceptions: gastrointestinal surgery. You should follow the instructions of your attending physician).

  • Discuss with your physician if you may take your regular medication. Diabetic patients must make sure to consult their physician too.
  • You may want to prepare something to eat after you have had the injection. Alternatively, you can always get something to eat at the hospital restaurant.

Pregnancy and breastfeeding

Are you pregnant or do you think you may be pregnant? Or are you breastfeeding? Please tell the physician before the injection. The test will not be performed if you are pregnant. If you are not sure whether you are pregnant or not, the test will be postponed until you are certain.

If you are breastfeeding, make sure to discuss this with the physician before the test. You will receive additional instructions about how to avoid unnecessary radiation exposure in your child.

Part one - stress test

On the first day, cardiac exercise is performed in the Heart Centre on the first floor (gate E). This will be done by means of a cycling test. This cycling test takes approximately 10 to 15 minutes, depending on the effort you are capable of. During the test, a radioactive substance is administered.

In the case of people who, for some reason, are unable to produce maximal effort on the bicycle, the cardiologist may sometimes choose to mimic exercise using medication such as Persantin or Dobutamine. These products will be injected through an IV needle while the electrocardiogram and blood pressure are being monitored. These products replace the cycling test. Before administering this medication, the physician will check if you are contraindicated for it. After the test, 99 mTc-MIBI will be injected through the IV line.

Then, you will be referred to the Nuclear Medicine Department where you must check in. On completion of the administrative procedures, you will have to eat something.

You are expected to return to the department after approximately one hour. Electrodes are placed on the chest in order to record an electrocardiogram (ECG) during the test. Then, recordings are made. These will take about 15 minutes.

An appointment will be made for the second part of the procedure.

Part two - test at rest

Please come directly to the Nuclear Medicine Department. There, a radioactive substance will again be administered intravenously in the arm. After that, you will be asked to go and eat something. After about 30 minutes, recordings will be made in the same way as on the first day. These will again take about 15 minutes.

After the test

Unless you are an inpatient, you may resume your normal activities afterward.

What are the risks?

You may be slightly short of breath during the stress test. This is normal and generally resolves by itself. Let the physician know if you feel pain or pressure in your chest. You will be monitored continuously during the procedure by means of an electrocardiogram and blood pressure monitor. These measurements allow for the timely detection of any heart rhythm disturbances. Equipment and medication to treat any potential heart rhythm disturbances are always available. The injection of Persantin may result in slight nausea and/or headache afterward. This usually disappears by itself.

Safety and radiation

The injected product has essentially no side effects. It causes no abnormal sensations and only in very rare cases causes (very mild) allergic reactions. The injected radioactive material does constitute a dose of radiation, but it is very small (about as much as for a regular CT scan). The quantity of radiation that you are exposed to during the test is not higher or lower depending on the number of images taken.

The radioactive substance will have disappeared almost completely from your body after 12 hours. It is recommended that children younger than the age of 6 do not sit on your lap for more than half an hour during the first 12 hours after the test. Playing, feeding, changing sheets and nappies and other daily activities are no problem. Prolonged contact (longer than one hour) in close proximity (less than one metre) with pregnant women during the first 12 hours should be avoided too.

Results

The Nuclear Medicine Department will prepare a report of the test. That report and the images will be digitally available for the physician who requested the test the following day.

By comparing the results of the first scintigraphy with the second one, we will have a reliable picture of the blood flow through the heart during exercise and at rest. This will allow us to draw the necessary conclusions and, if required, to initiate or adjust treatment. The results will always be sent to your cardiologist and/or GP.

Centres and specialist areas

Nuclear Medicine
Cardiology

Latest publication date: 05/02/2021
Supervising author: Dr Van Den Bossche Bieke, Dr Provenier Frank