A PATIENT GUIDE TO MYOCARDIAL PERFUSION IMAGING ALSO KNOWN AS NUCLEAR STRESS TESTING
WHAT IS CORONARY ARTERY DISEASE?
Coronary Artery Disease (CAD) is caused by inadequate blood supply to the heart, usually caused by blocked arteries.
WHAT IS A MYOCARDIAL PERFUSION IMAGING STRESS TEST?
Myocardial Perfusion Imaging stress testing is usually done in Nuclear Medicine department or Cardiac Clinics. They may perform the test on an outpatient or inpatient basis. This test involves an injection of a small amount of radioactive material, which circulates in the bloodstream and shows if your heart muscle is receiving adequate blood supply under stress and/or rest conditions. The radioactive injection is a clear liquid call Cardiolite™ . Other material which could also be used are MYOVIEW™ and thallium.
HOW SAFE IS A MYOCARDIAL PERFUSION STRESS TEST?
Any stress procedure may have some risks, and you should consult with you cardiologist regarding the risks and benefits of this procedure. The radioactive materials Cardiolite™ and thallium have been shown to be safe, with a low incidence of adverse reactions. This test and these materials are used routinely worldwide, under cardiologist supervision.
Neither Cardiolite™ nor thallium are "dyes," and there usually are no serious side effects from their injection.
WHY WOULD MY DOCTOR ORDER A MYOCARDIAL PERFUSION IMAGING STRESS TEST INSTEAD OF A REGULAR STRESS TEST?
Under certain circumstances, a regular stress test may yield indeterminate results. To improve the diagnostic accuracy, your cardiologist may request a Myocardial Perfusion stress test.
HOW IS THE TEST PERFORMED?
The test usually consists of two sets of imaging; before and after exercise. There are many variations for performing the test, which depends on the department's routine procedure. The entire test may be completed in one day or two separate days. You will be informed if the exercise or rest portion will be done first. Cardiolite™ will be administered by injection, before and again, during peak exercise and once again while you are at rest.
As in a regular stress test, ECG electrodes will be attached to your chest. This will allow your cardiologist to monitor your heart rate before, during, and after exercise. A blood pressure cuff will be placed on your arm to monitor your blood pressure before, during and after exercise. Additionally, a small plastic needle will be placed in your hand or arm vein to allow for ease of the Cardiolite™ injection. The needle will be removed when the exam is completed.
The exercise part of the exam is usually done by pedaling a stationary bicycle in our lab. Sometimes, treadmills are also used. Exercising will begin slowly, and approximately every two to three minutes the pace will gradually increase. If you pedal a stationary bicycle, it will feel easy to pedal at first, then it will gradually get harder. As you exercise, your heart rate and blood pressure will change. This is normal, and remember, you are being closely monitored throughout the exam. At your peak exercise, Cardiolite™ will be injected via the small needle, and you will be asked to continue exercising for an additional one or two minutes. You will be encouraged to continually exercise throughout the stress exam. If you experience any unusual symptoms at any time, such as lightheadedness, immediately tell the individual monitoring the test.
Pictures of your heart will be taken using a special camera able to trace either the Cardiolite™ or thallium that has accumulated in your heart. You will be asked to lie down on a special table. The camera will rotate above and around your chest while special pictures are being taken, which will take approximately 20 to 30 minutes to complete. You may breathe normally while the pictures are being taken. It is very important that you hold very still while the camera take the pictures of your heart. You will not receive any radiation from the camera.
The resting pictures are taken in the same manner as the exercise pictures. Remember, the order in which pictures are taken depends on the department's routine imaging procedure. The total time needed for the test also varies and may take from two to three hours.
WHAT HAPPENS IF I AM UNABLE TO EXERCISE?
Some people, because of a variety of disabilities, are unable to exercise adequately on the stationary bicycle to achieve a diagnostic test result. In these cases, your cardiologist will decide whether to use IV PERSANTINE to stress your heart. For more information on IV PERSANTINE, click here.
ARE THERE ANY SPECIAL PREPARATIONS/INSTRUCTIONS FOR THE MYOCARDIAL PERFUSION IMAGING STUDY?
CLOTHING
You should wear comfortable, loose-fitting clothing for exercise and comfortable shoes appropriate for walking.
FOOD
Your cardiologist may instruct you to fast or to have a light breakfast and avoid certain foods such as milk products or caffeine-containing beverages. Additionally, you may be asked not to eat or drink 3 or 4 hours prior to the test. The pictures of your heart are more clear when the stomach is not full. If you are diabetic or insulin-dependent, consult with him/her on such dietary restrictions and insulin use.
MEDICATIONS
Consult with your cardiologist regarding whether certain medications should be taken before, or held until after, the test. Certain medications may interfere with the effectiveness of the exam.
WORK
Depending on the department procedure, time permitting, you may have time to go back to work between the two parts of the exam. The physician will inform you if this is possible.
PRECAUTIONARY INFORMATION
The Cardiolite™ administered during this stress exam contains a small amount of radioactivity. The amount of radiation you will be exposed to is comparable to that from an X-ray or CAT (CT) scan. If you are pregnant, suspect you may be, or are a nursing mother, discuss this with your cardiologist before undergoing the procedure. Adverse patient reaction to Cardiolite™ is rare. You may briefly notice a metallic taste a few seconds after injection has occurred. Other side effects have occurred rarely.
The information presented here is not a substitute for a discussion between your and your cardiologist. Consult your cardiologist if you want more information on the procedures and medication described
