What is a Nuclear Cardiology Test?
Nuclear cardiology tests measure the amount of blood flow to the heart muscle. Doctors use these tests to diagnose and assess coronary artery disease and cardiac ischemia (decreased blood flow and oxygen to the heart muscle). These tests are also called heart perfusion imaging tests or cardiac nuclear stress scans.
Two Types of Nuclear Cardiology Tests
We are one of only a few heart centers to offer two types of nuclear cardiology tests:
- Cardiac SPECT (Single Photon Emission/ Computed Tomography)
- Cardiac PET-CT (Positron Emission Tomography/ Computed Axial Tomography)
Both tests begin with an injection of radioactive chemicals (radionuclides) into your bloodstream through an IV. The radionuclides give off gamma rays, which are detected by imaging equipment that includes a gamma camera plus an attached CT scanner. The resulting picture, called a nuclear or PET scan, helps your doctor assess blood flow to your heart muscle and assess heart function.
During cardiac PET-CT, additional images and measurements are taken, including the following:
- Structural (or anatomical) images of your coronary arteries
- A calcium score, or a measurement of the calcium deposits in your coronary arteries
- A measurement of blood flow to your heart muscle tissue. This helps your doctor determine if you have disease in more than one of your coronary arteries (called multi-vessel disease)
Stress Test Component
Nuclear cardiology tests can be done under conditions of rest and stress. During the test, images are first taken of your heart while you are at a relaxed heart rate.
Then, you exercise on a treadmill. If you cannot exercise, the technician can administer a medication that stresses your heart as if you were exercising.
Measuring your heart function under stress helps your doctor assess blockages in the flow of blood to your heart. Doctors may also call this exam a nuclear stress test.
Reasons for Nuclear Cardiology Tests
Nuclear cardiology tests are used for several purposes:
- To evaluate blood supply to areas of damaged heart muscle after a heart attack
- To assess whether you have coronary artery disease and to measure how much your arteries are blocked
- To predict if you would benefit from additional procedures, such as cardiac catheterization or bypass surgery
- To measure the effectiveness of treatments such as cardiac catheterization or bypass surgery
- To determine impact of coronary calcium and coronary ischemia on your heart muscle
- To assess your need for treatment with medications and lifestyle changes versus medical procedures or surgeries