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?
- 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
- You will need to lie as still as possible whilst each picture
- 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
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.