- Nuclear imaging is used to evaluate blood flow to the heart.
- During nuclear imaging, physicians inject a small amount of a radioactive isotope, called a tracer, into a person’s bloodstream.
- Cameras record the distribution of the isotope through the bloodstream and heart muscle and produce images of the heart that help physicians evaluate heart function or locate exactly where the heart muscle may not be receiving enough blood.
- A nuclear stress test adds an exercise component to the test to measure how well the heart responds to exertion from exercise.
Nuclear imaging is one way that a physician diagnoses coronary heart disease, a condition caused when a waxy substance called plaque builds up inside the coronary arteries, which are the major blood vessels that supply the oxygen-rich blood to the heart muscle.
The test is also used to evaluate cardiomyopathy, a chronic disorder of the heart’s muscle function, and other types of heart conditions.
During nuclear imaging, a small dose of a radioactive isotope is injected into the bloodstream. The radioisotope, or tracer, is carried through the bloodstream and into the myocardium, or heart muscle. Special cameras detect the radiation released from the tracers and record information about the heart muscle and blood flow. This information is then used to produce images of the heart on a computer screen.
The different types of nuclear imaging include:
- Myocardioal perfusion scan, used to evaluate blood flow, and
- Radionuclide ventriculography, which measures ejection fraction, stroke volume, and cardiac output.