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Stress MIBI: Testing Your Child's Heart

What is a stress MIBI?

A stress MIBI is a test that checks how well blood is flowing though your child's heart.

During the test, a small amount of radioactive material called MIBI is injected into your child's blood. Then, special cameras take pictures of your child's heart from different angles. The radioactive material lets the camera take very detailed pictures of how the blood flows through the heart.

The amount of radioactive material used in the test is very small and will not harm your child.

The test has two parts:

  • First your child's heart is tested while your child relaxes.
  • Then your child does an exercise test.

Imaging for the test usually takes about 15 to 20 minutes for each part. However, it is likely that you and your child will be at the hospital all day.

What is an exercise test?

An exercise test is sometimes called an exercise electrocardiogram, an exercise ECG, or a stress test. An ECG is a recording the rhythm of the heart.

The exercise test shows how your child's heart works when he or she does things like walk, run, and bicycle. It can help the heart doctor, or cardiologist, see any problems with your child's heart. These tests give information the doctor cannot measure while your child sits or rests. The doctor can also see how your child's heart works compared to other children's hearts.

Your child should sleep well and get a good breakfast before the test

These are the things your child should do to get ready for the test:

  • Your child should get a good night's sleep before the test.
  • Your child should eat a good breakfast on the day of the test. A good breakfast includes servings of grains, protein, and fruit. One example of a good breakfast is egg, peanut butter, or cheese; toast; juice or fruit; and milk.
  • Your child should eat a good lunch, too. Make sure your child finishes lunch at least 1 hour before the exercise test.
  • Your child should wear or bring a T-shirt, shorts, and running shoes for the test.
  • Your child should be prepared to exercise.

A nuclear medicine technologist gives the test

Nuclear medicine technologists are people who are trained to give the tests on the machines in the hospital. The exercise part of the test is given by two cardiology technologists as well as the nuclear medicine technologist.

The first part of the stress MIBI test: taking pictures of your child's heart at rest

The first part of the stress MIBI takes pictures of the blood flowing to your child's heart while he or she is relaxing. To take these pictures, the technologist will put a small tube into a vein in your child's arm. The tube is called an intravenous (IV) tube. Once the IV is in place, the technologist will put a small amount of radioactive medicine called MIBI into the IV tube. The IV tube will stay in your child's arm for the day. This is because MIBI has to be given to your child for both parts of the test.

It takes about 1 hour for the MIBI medicine to collect in your child's heart muscle, so your child must now wait about 1 hour before the technologist can take the pictures. You can leave the department and the technologist will tell you what time to come back to have the pictures taken.

Your child will be asked to eat or drink something that has fat in it approximately half an hour after the MIBI injection. Examples of foods with fat in them are a muffin or a donut. You can also give your child 2% or whole milk. The fat contained in these foods helps to give a clear picture of your child's chest and tummy. Your child should have this food before you bring him or her back to have the pictures taken. You can bring this food with you, or buy it in the hospital cafeteria.

Taking pictures of your child's heart

When you bring your child back to the nuclear medicine lab, your child will lie down on a special bed. Then the nuclear medicine cameras will move around your child and take a set of pictures. This does not hurt, but your child will need to lie still for about 30 minutes. He or she can watch a videotape or DVD while the pictures are taken. There are some videotapes and DVDs at the hospital for your child to watch. You can also bring one of your child's favourites from home.

After the pictures are done, your child can have a small lunch, such as soup and crackers, or a sandwich. Your child is then ready for the second part of the test.

The second part of the stress MIBI test: taking pictures of your child's heart after exercise

The second part of the stress MIBI includes an exercise test. Your child will need to walk on a treadmill, which is like a moving sidewalk, or ride a special bicycle. While your child is exercising, the technologist will monitor the rhythm of your child's heart.

Explain to your child that he should follow the directions for the test. Your child should try his or her best. In this way, the doctors can get the most accurate results. They will have a clearer picture of your child's heart and how it works. We know it will not be easy, but we need your child to work as hard as possible during the test.

Just before the test starts, a technologist will attach a long tube to your child's IV. The tube is long so that it will reach your child while he is on the treadmill or bicycle. MIBI material will be put into the IV tube as your child is exercising.

When the exercise test is finished, your child will be asked to sit in a wheelchair. You and your child will go back to the nuclear medicine department to have the last set of pictures taken. This will take about 30 minutes. When the pictures are finished, the technologist will take out the IV tube. You can then take your child home.

After the test is over

Your child should drink lots of liquids, such as water, juice, or milk, during the rest of the day. This will help your child's body get rid of the MIBI. Your child can eat as usual.

Getting the results of your child's test

Your child's cardiologist (heart doctor) will give you the test results in 10 to 14 days. If a problem is found during any of these tests, the technologist will tell your child's cardiologist right away.

Key points

  • A stress MIBI is a test that examines your child's heart and blood flow.
  • The test uses radioactive material and special cameras to take pictures of the inside of the body.
  • The amount of radioactive material used is very small and will not hurt your child.
  • The cameras take pictures while your child is at rest and while your child is exercising.

Maria Green, MRT(N)
Gareth Smith, MSc
Susan McQuattie, MRT(N)
Martin Charron, MD, FRCP(C)
Jennifer Russell, MD, FRCPC


At SickKids:

The first part of test is done in the Nuclear Medicine department of the hospital, on the 2nd floor of the Elm Wing. Morning check-in is at the Diagnostic Imaging department, also on the 2nd floor of the Elm Wing.

The second part of the test is done on the 4th floor of the hospital on ward 4B. For this part of the test, please check in at the Heart Station registration on ward 4B by 12:30 in the afternoon.

If you have any questions about the test or need to cancel the test, please call Nuclear Medicine at 416-813-6065.