Nuclear Cardiology

The Oklahoma Heart Institute nuclear cardiology laboratories were the first Intersocietal Commission for the Accreditation of Nuclear Medicine Laboratories (ICANL) in the state of Oklahoma. We sought accreditation to show our commitment to high quality nuclear cardiac imaging. Our labs have set forth strict protocols that ensure accurate testing, patient safety and correlation with clinical symptoms and previous diagnostic tests.  Studies are interpreted by a select group of formally trained and dedicated noninvasive cardiologists. All interpreting cardiologists have attained the training and requirements to be licensed as authorized users of radiopharmaceuticals as outlined by the State of Oklahoma and the American Society of Nuclear Cardiology.

What is Nuclear Cardiology?
Nuclear Cardiology is a noninvasive imaging technique that demonstrates a highly reliable assessment of blood flow in the heart muscle and function. It can effectively evaluate cardiac status at all stages of coronary disease by utilizing sophisticated gamma camera equipment that measures coronary blood flow from the uptake of an intravenous injection of radioactive isotope localized in the myocardium.

Studies Offered at Oklahoma Heart Institute

This procedure gives your physician the ability to view the flow of blood to the heart muscle. This helps them determine if your heart is receiving enough blood, if you have coronary artery disease (CAD) and if additional testing is required.

How does MPI Work?
There are two parts to this test that can be done in either order.

Part 1: The heart is stressed - the arteries are dilated or enlarged by means of exercise or by a prescription medication that helps create an effect on the heart similar to exercise. The healthier the coronary arteries are, the more dilated they will become. Once the coronary arteries are enlarged through dilation, a trace amount of radioactive imaging agent is then injected. A special camera is then used to take images of your heart. These images will show if there is any part of your heart that is not getting enough blood.

Part 2: Two sets of images of your heart will be taken by a special camera – one when your heart is stressed and the other when it is at rest. These images will take about 10 minutes while you are relaxing comfortably on your back with your arms extended above your head. Both sets of images will be compared and checked for differences. If you have healthy coronary arteries, there will be little to no difference between images, however if you have narrowed arteries there will be differences.

*The radiation amount you will receive during this test is the same or less than what you would receive during a normal x-ray and your body quickly gets rid of the radioactive imaging agent through natural means.

How Should I Prepare for this Test?

  • Talk to your physician to find out if you should stop taking any medications prior to this test (if you’re diabetic and take insulin or oral hypoglycemic medications you’ll have special instructions to follow)
  • Let your physician know if you have a history of wheezing, asthma or chronic lung disease
  • Do not eat or drink for 3 – 6 hours prior to this test
  • Do not consume caffeinated products for at least 24 hours prior to this test
  • Do not apply creams, powder or lotions to your chest area the day of this test
  • Be sure to wear comfortable clothes and shoes for brisk exercise on a treadmill

What if I Need Medication to Dilate My Arteries?

If you are not able to exercise briskly on a treadmill, you will be given a dilating medication for approximately 4 – 6 minutes. A blood pressure cuff will be on one arm while a small intravenous needle will be inserted into the other arm. Small round pads with wires attached leading to an electrocardiograph (ECG) will be carefully attached to your chest. Your physician will be continually monitoring your heart throughout this process. You may feel effects that mirror those of exercise including flushing, chest pain or pressure and shortness of breath. Most of these feelings will stop once the infusion has ended.

This imaging test involves labelling the red blood cells in your blood with a radiopharmaceutical and then measuring the amount of blood in the heart during different parts of the heartbeat. This is the analysis of the amount of radioactive blood pooling in the heart chambers at different times of an average cardiac cycle.

Left Ventricular Ejection Fraction (LVEF) – the measurement of how much blood is being pumped out of the left ventricle of the heart (the main pumping chamber) with each contraction.

Right Ventricular Ejection Fraction (RVEF) – the measurement of how much blood is being pumped out of the right ventricle of the heart (the main pumping chamber) with each contraction.

Multigated Acquisition Scan (MUGA) – noninvasive, highly accurate diagnostic test used to evaluate the pumping function of the ventricles or lower chambers of the heart. During this test, a small amount of radioactive tracer is injected into a vein. A special camera (gamma camera) detects the radiation released by the tracer to produce computer-generated images of the beating heart.

This test is designed to help your physician determine how well your heart works under pressure. This will reveal whether or not your heart is receiving enough oxygen and blood flow when it needs it most. A physician may recommend this test to those currently experiencing chest pain, to help diagnose coronary artery disease or to determine a safe level of exercise. If you are over 40 years of age and a smoker or have other heart disease risk factors, you should talk to your physician to find out if an exercise stress test may be good for you.

What to Expect

  • You will be hooked up to an EKG machine.
  • Several sticky pads will be placed on your skin under your clothing.
  • Your heart rate and breathing will be checked before you begin exercising.
  • You will then start walking slowly on the treadmill. As the test progresses, the speed and grade of the treadmill will be increased. You may request to stop this test at any time.
  • Afterwards, your heartrate and blood pressure will be checked.
  • A few days later, your physician will review the results with you.If your results show that you may have coronary artery disease or other heart problems, you may begin treatment or have further testing, such as a nuclear stress test.