Strong Heart and Vascular Center

Diagnosis and Treatment

Myocardial Perfusion Imaging

What This Test is Designed To Do:

This is the most widely used type of nuclear cardiology test. It provides more information than routine exercise stress tests, helping doctors recognize which patients are at an increased risk for a heart attack or are candidates for procedures such as coronary angiography, angioplasty and heart surgery. It may also be prescribed for pre-operative evaluation for non-cardiac surgery.

The test can:

Identify areas of the heart muscle that have an inadequate blood supply
Quantify the extent of the heart muscle with a limited blood flow
Provide information about the heart’s pumping function
Ascertain the amount of scarring from a heart attack
Evaluate the success of coronary bypass surgery or angioplasty

What To Expect:

This test is done in two parts. The first part shows the heart during normal functioning, called "rest." During the second part, called "stress," the coronary arteries are dilated through exercise. You may walk on a treadmill or ride a stationary bicycle. If your aren’t able to exercise maximally, you may receive a "chemical" stress test. You’ll be given a drug, such as Adenosine or Dobumatine, which makes your heart react as if you were exercising.

We use a dual isotope SPECT testing system. SPECT is an acronym for Single-Photon Emission Computed Tomography. Dual isotopes means one radioactive isotope or tracer, thallium, is used for the rest part of the test; a second isotope, Cardiolite (a tradename for technetium-99 sestamibi, a synthesized radioactive tracer) is used for the stress part.

Small amounts of these tracers are injected. They concentrate in those parts of the heart with the best blood flow and emit signals that can be detected by the specialized camera. Images taken by the camera show if any part of your heart is not getting enough blood.

Images from each part of the test are compared. A relatively healthy heart shows little or no difference between images taken during stress and rest. But a heart with partially blocked arteries will show differences in these images.

Each set of pictures takes between 15-30 minutes. The entire test takes between 3-5 hours and you will need to stay in the laboratory for the entire time.

You may experience shortness of breath, chest or arm pain or discomfort, palpitations, headache, flushing, difficulty walking, fatigue or other symptoms during the test. Always tell the people doing the test how you feel, so they can take any action needed.

Risks:

The test MAY NOT be appropriate for patients who have or have had:

Asthma
Glaucoma
A recent heart attack
Irregular heart rhythms (arrhythmia)

Patient Preparation:

Tell the doctor, technologist, or nurse doing the test, if you have a history of allergies, are taking any medications (including over-the-counter medications or "natural" supplements), are diabetic, are pregnant or suspect you are pregnant, are breast feeding your baby, or have any prosthetic implants in your body.

You will be asked to not eat for a few hours prior to your test. This time will vary depending upon the type of test you are having, the time of day of the test and your medical condition. You should not consume any caffeine for at least 12-24 hours prior to the test. This includes coffee, tea, soft drinks containing caffeine, and chocolate. Some patients may be asked to stop taking certain medications. You should wear loose clothing and low-heeled, rubber-soled shoes or tennis shoes. If you smoke, please refrain from smoking for at least four hours before your test.

NOTE: The radiation levels administered in most nuclear medicine studies are usually considerably lower than in a conventional x-ray or CT scan. Patients retain this low level radioactivity for relatively short periods. It dissipates on its own, and some is eliminated through urine or bowel movement.