Doctors use the images from a nuclear stress test to measure blood flow to a patient's heart before and after exercise, and in some cases before and after taking medications, notes Mayo Clinic. They conduct the test by injecting a radioactive dye into the patient's blood stream, then studying images of the dye's flow through the heart and heart muscles.
Coronary arteries are the main avenue by which blood and nutrients flow to the heart, states Mayo Clinic. Some people experience a buildup of plaque in the arteries or other conditions that disrupt blood flow. Doctors compare the images from nuclear stress tests to identify these buildups and diagnose coronary heart disease. Doctors also use the images from nuclear stress tests to determine if a patient's heart is enlarged and measure the ejection fraction, or pumping ability, of a patient's heart.
Doctors also use nuclear stress tests when other tests do not pinpoint the cause of a patient's chest pains, notes Mayo Clinic. Doctors treating patients with heart disorders such as coronary heart disease or arrhythmia,use nuclear stress tests to determine how well existing treatment plans are working. If the images from a stress test indicate that a patient continues to experience decreased blood flow to the heart, the doctor may change the treatment plan.