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Nuclear Cardiology

Why has my doctor ordered a nuclear cardiology test?

Nuclear medicine cardiac stress-rest testing is a powerful tool used to see pictures of your heart shortly after you have exercised and/or while you are resting. Like all nuclear medicine procedures, nuclear stress-rest tests offer a way to collect medical information that may be difficult to get with traditional procedures.

Nuclear stress-rest tests can be used to examine the blood flow to the heart, determine the amount of damage to the heart muscle after a heart attack, diagnose the cause of chest pain (angina), or check the health of your arteries. This information can help your physician develop the best treatment plan for your long-term heart health.

You may have a number of questions about your procedure: How do these tests work? How should I prepare for it? What will I experience?  We will attempt to answer some of your questions below.  If you have additional concerns, your doctor and/or the trained technologist performing your procedure will be able to help address those questions.

What is Nuclear Medicine?

Nuclear medicine is a medical specialty that uses the nuclear properties of matter to help diagnose and treat medical conditions. Nuclear medicine is unique because it provides doctors with information about both the structure and function of organs. Millions of nuclear medicine procedures are performed each year in the United States.

Nuclear medicine procedures work by using small amounts of radiopharmaceuticals (also called tracers) that are injected, swallowed or inhaled. There are different tracers that target different parts of the body. The unique feature of these tracers is that they are attached to a very small amount of radioactive material, which releases radioactive energy (gamma rays) or particles (positrons) that are detected by (gamma rays) or particles (positrons) that are detected by special cameras. These cameras are used with computers to create very detailed pictures that help the physician see what is happening inside your body.

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How does a Nuclear Medicine Cardiac Stress-Rest Test Work?

Nuclear cardiac scans provide information about circulation and function. A traditional stress test with an ECG measures only the heart’s electrical activity. In comparison, the nuclear medicine cardiac stress-rest test helps the doctor to see the heart in action when you are resting, exercising, or both. The results allow your doctor to check if there is adequate blood flow to your heart, whether blood vessels are blocked, and whether the heart cells are functioning properly.

Here’s what the results of a nuclear stress-rest test can show. If the test shows that blood flow is normal while you are resting, but not normal while you are exercising, then doctors know that blood flow to your heart is not adequate during times of stress. The heart normally pumps more blood during times of physical exertion.

If the test results are not normal during both rest and exercise, then part of your heart may be permanently deprived of blood. If doctors cannot see the radioactive substance in one part of your heart, it probably means that a section of the heart muscle has died, either because of a previous heart attack or because the coronary arteries supplying blood to that area of the heart are blocked.

Are there any concerns with Cardiac Stress-Rest Tests?

Don’t let the words “nuclear” or “radioisotope” scare you. Nuclear medicine procedures are designed to expose you to the least amount of radiation possible while successfully performing the procedure.

All radiopharmaceuticals are prepared with exceptional care and have been thoroughly tested and approved by the U.S. Food and Drug Administration. However, there is always a chance that patients may have a reaction to the drugs, and it is important to tell your physician or the technologist performing the test of any side effects that you may experience. If you are pregnant or breast feeding, be sure to talk with your physician before any nuclear medicine procedure.

What will the Cardiac Stress-Rest Test be like?

Although the exact procedures vary, all nuclear stress-rest tests have similar structure: administration of tracer, followed by a waiting period, followed by exercise, followed by imaging under the required conditions (rest or stress).

When you arrive, tell the technologist about any health problems that may interfere with your ability to exercise such as asthma, chronic lung problems, or problems with your balance, knees, hips, etc. Either before, during, or after the exercise portion of the test you will receive one or more intravenous injections of the tracer. After each injection, images may be taken almost immediately or after a waiting period to allow the tracer to travel to the heart and accumulate in the heart tissue. The number of injections you receive and the length of any waiting period will depend on the type of test.  A major purpose of the stress-rest test is to compare images of your heart at rest with images taken during or immediately after intense exercise. The resting images will be obtained before you exercise.

During the stress part of the test, you will be asked to walk on a treadmill or pedal a stationary bicycle until you reach your highest possible level of exertion. During this time, your blood pressure will be taken and your heart will be carefully monitored with an ECG. Images will either be taken while you are exercising or immediately after you stop. This will let your doctor see how well your heart works when blood flow is at its peak.

If you are unable to exercise due to a medical condition, a pharmacological stress test (also called a chemical stress test) will be performed. In this procedure, a medication that causes the heart to act as if you were exercising is administered.

How long does the Cardiac Stress-Rest Test take?

Nuclear stress-rest tests are more time consuming than many other tests. The entire procedure usually takes 2 hours, depending on the type and purpose of the scan. Your doctor and/or technologist will inform you of the length of your procedure in advance.

What type of Nuclear Cardiology Test will I be having?

There are several types of nuclear cardiac stress-rest imaging procedures. Here is a brief description of the test we perform:

SPECT scans: This imaging method uses quick-acting tracers to create 3-dimensional cross-sectional (tomographic) images of the heart’s structures and function. The SPECT camera rotates around the patient, taking pictures as the tracer is absorbed by the heart muscle. SPECT scans are used to locate blockages of blood vessels in the heart, to determine the effectiveness of previous treatment. These scans may sometimes be used to take real-time images during exercise to better assess the condition of the heart.

Is special follow-up needed after my Cardiac Stress-Rest Test?

The radioactive tracer usually does not remain in your body for a long time. Unless there is some reason that you should not drink a lot of fluid, it is advisable to drink plenty of liquids and urinate frequently after the test is complete. This will help flush any remaining radioactivity out of your body.

Usually, you can resume most normal activities, including your normal medication schedule, immediately. Be sure to ask your doctor for any special follow-up instructions specific to your situation.

How will I learn the results of my nuclear Stress-Rest Test?

A Med Health Services physician trained in nuclear medicine will review your images, prepare a written report, and discuss the results with your doctor. Your doctor will then explain the results to you and discuss any further tests or treatments that may be needed.

Preparing for your Cardiac Stress-Rest Test:

Wear tennis shoes or comfortable shoes as you will be asked to walk on a treadmill or ride a stationary bike. You should wear comfortable clothes with preferably an open shirt without metal snaps or buttons. Do not apply lotion or powder to your chest area as this could minimize the effectiveness of the electrodes being placed for an accurate EKG. You can drink anything non-caffeinated 2 hours prior to your test. You should not drink anything with caffeine or have any nicotine 4 hours prior to your exam as caffeine/nicotine raises your blood pressure unnaturally. (Diabetics should follow their regular eating and medication routine). Please do not take any heart or blood pressure medicine 24 hours prior to your exam.