Cardiac Perfusion Scan (Medicine): About This Test

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What is it?

Heart and coronary arteries

A cardiac perfusion scan measures the amount of blood in your heart muscle at rest and after your heart has been made to work hard.

During the scan, a camera takes pictures of your heart after a radioactive tracer is injected into a vein in your arm. The tracer travels through the blood and into your heart. As the tracer moves through your heart, areas that have good blood flow absorb the tracer. Areas that do not absorb the tracer may not be getting enough blood or may have been damaged by a heart attack. The pictures show this difference.

Two sets of pictures may be made during the test. One set is taken while you are resting. Another set is taken after your heart has been made to work harder (called a stress test). The heart can be stressed by using medicine or exercise. This information is about using medicine to stress the heart.

This test is also known by other names, including myocardial perfusion scan, myocardial perfusion imaging, thallium scan, sestamibi cardiac scan, and nuclear stress test.

Why is this test done?

The test is often done to find out what may be causing chest pain or pressure. It may be done after a heart attack to see if areas of the heart are not getting enough blood or to find out how much your heart has been damaged from the heart attack.

How can you prepare for the test?

Tell your doctor if:

  • You take medicine for an erection problem, such as sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra). You may need to take nitroglycerin during this test, which can cause a serious reaction if you have taken a medicine for an erection problem within the past 48 hours.
  • You have had bleeding problems, or if you take aspirin or some other blood thinner.
  • You are or might be pregnant.
  • You are breastfeeding. Don't use your breast milk for 1 to 2 days after the scan. Use formula instead.

What happens during the test?

Resting or baseline scan

  • You will take your top off and be given a gown to wear.
  • Electrodes will be attached to your chest to keep track of your heartbeats.
  • Your arm will be cleaned. You will have a tube, called an IV, going into your arm. A small amount of the radioactive tracer will be put in the IV.
  • You will lie on your back or your stomach on a table with a large camera positioned above your chest. The camera records the tracer's signals as it moves through your blood. The camera does not produce any radiation, so you are not exposed to any additional radiation while the scan is being done.
  • You will be asked to remain very still during each scan, which takes about 5 to 10 minutes. The camera will move to take more pictures at different angles. Several scans will be taken.

This test takes about 30 to 40 minutes.

Stress scan using medicine

The stress scan is done in two parts. In many hospitals, you first have the resting scan. You are then given a medicine that makes your heart work harder and you have another scan. Sometimes the stress scan is done first.

  • You will have a test called an electrocardiogram (EKG or ECG), which takes about 5 to 10 minutes. You may have other EKGs during and after the stress test.
  • Medicine will be put in your IV. It will make your heart work harder. You may get a headache and feel dizzy, flushed, and nauseated from the medicine, but these symptoms usually do not last long.
  • Your heartbeat and blood pressure may be checked.
  • Your symptoms such as chest pain and shortness of breath will be checked.
  • A few minutes after you get the medicine, another small amount of radioactive tracer is injected. You may be given something to reverse the medicine used to make your heart work harder.
  • You will wait for 30 to 40 minutes and then have another resting scan. See the "Resting or baseline scan" section.

This test takes about 30 to 40 minutes.

What else should you know about the test?

  • Sometimes more pictures are taken 2 to 4 hours after the stress scan.
  • No electricity passes through your body during the test. There is no danger of getting an electrical shock.

What happens after the test?

  • You can go back to your usual activities right away.
  • You will probably be able to go home right away.
  • Drink plenty of fluids for the next 24 hours to help flush the tracer out of your body. If you have kidney, heart, or liver disease and have to limit fluids, talk with your doctor before you increase the amount of fluids you drink.

When should you call for help?

Call 911 anytime you think you may need emergency care. For example, call if:

  • You passed out (lost consciousness).
  • You have been diagnosed with angina, and you have angina symptoms that do not go away with rest or are not getting better within 5 minutes after you take a dose of nitroglycerin.
  • You have symptoms of a heart attack. These may include:
    • Chest pain or pressure, or a strange feeling in the chest.
    • Sweating.
    • Shortness of breath.
    • Nausea or vomiting.
    • Pain, pressure, or a strange feeling in the back, neck, jaw, or upper belly or in one or both shoulders or arms.
    • Light-headedness or sudden weakness.
    • A fast or irregular heartbeat.
    After you call 911, the operator may tell you to chew 1 adult-strength or 2 to 4 low-dose aspirin. Wait for an ambulance. Do not try to drive yourself.

Call your doctor or nurse call line now or seek immediate medical care if:

  • You have had any angina symptoms, such as chest pain or pressure, even if they have gone away.
  • You have new or increased shortness of breath.
  • You are dizzy or light-headed, or you feel like you may faint.

Watch closely for changes in your health, and be sure to contact your doctor or nurse call line if you have any problems.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

Go to http://www.healthwise.net/ed

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