Medical abbreviation:
MIBI, MPS
Type:
Radionuclide test
Definition:
A myocardial perfusion scan is also known as a thallium scan. The scan involves injecting the patient with a dye containing a radioisotope. The radioisotope used varies and can be thallium, tetrofosmin or technetium. The dye is taken up by the blood stream and “illuminates” (the radioisotopes emit gamma rays) blood flow to different regions of the heart to a gamma camera. The test normally has two phases, a rest and a stress phase; in some cases only a stress test is done.
The rest phase occurs when the dye is first injected and pictures are taken using the specialised camera. The stress phase involves giving another dose of the of radioisotope and then the heart is “stressed”, this can be by making the patient exercise or injecting a drug which speeds up the heart. Further pictures are taken during the stress phase.
When would I need this test?
This scan is done to assess whether any parts of the heart are being deprived of oxygen, doctors refer to this as ischaemia. The test can be used to diagnose conditions like angina, but also to see if there have been any previous heart attacks. The test is also requested if it is felt a patient may not be fit enough to do an exercise tolerance test.
Important
Most centers will ask you to avoid food or drinks that contain caffeine prior to the test. The test is not suitable for pregnant women, if you feel you might be pregnant, you must tell your doctor or the radiographer. Always check with your local department regarding their protocols.
Risks
Myocardial perfusion scans are very safe and most people have no problems. Potential complications may include:
