Myocardial perfusion scan (MPS)

A myocardial perfusion scan – or MPS – uses a small amount of radioactive substance to create images which show blood flow to the heart muscle.

The test can also be known as a thallium scan, MIBI scan, technetium scan or nuclear medicine scan.

What can the scan show?

The myocardial perfusion scan looks at the pumping action of your heart and the flow of blood to your heart muscle. It can help diagnose coronary heart disease and may also be used by doctors to find out if you’d benefit from a coronary angioplasty or coronary bypass surgery.

What happens in the MPS test?

Remember:

  • Don’t have any food or drink containing caffeine (coffee, tea, chocolate, coca cola) for 24 hours before the test
  • If you are pregnant or think you might be, or are breastfeeding, tell your doctor as you might not be able to have the scan
  • You will need to lie as still as possible whilst each picture is taken
  • Try not to bring children to your appointment so they are not exposed to any unnecessary radiation

You will have a small amount of radioactive substance (often called a tracer, isotope or radionuclide) injected into your blood so that your blood flow can be detected by the special camera used in the test.

The camera will be positioned close to your chest to take pictures of different parts of your heart, similar to an x-ray.

The scan is usually in two parts – stress and rest – so that doctors can see the effects of physical stress (exercise) on your blood flow.

For the stress element, before you are injected with the tracer you will be asked to exercise on a bike or treadmill – or if you are unable to exercise you may be given a medicine instead which increases your heart rate. The camera takes pictures of your heart while you are exercising and your heart rate and blood pressure will be closely monitored throughout.

You will then have a break of about an hour, in which you should eat and drink to clear the radiation from your system. You will then go back for the rest part of the scan, which involves the same injection and camera, although this time you will just lie on the bed while the images are taken.

How long will it take?

Overall the appointment takes about 4 hours as there is some waiting around inbetween the two parts of the test. Sometimes the scans are taken over two days and in this case they will take around one to two hours each time. The actual scan usually only takes about 20 minutes.

Is the scan safe?

You will be exposed to some radiation during the test; however it is a small amount and is considered safe. There are usually no side effects or complications from a myocardial perfusion scan, and you can normally drive home afterwards.