An ejection fraction is most commonly measured during an echocardiogram. This painless and noninvasive test uses high-frequency sound waves (ultrasound) to get a picture of the four heart chambers and the four heart valves. An ejection fraction can also be measured as part of other diagnostic testing, such as:

• Cardiac catheterization. A test in which a catheter is inserted into a blood vessel and guided all the way to the heart in order to obtain information about the heart and the coronary arteries. Increasingly, this test is being replaced by noninvasive methods to measure ejection fraction.
  
  
• SPECT test. Like the MUGA scan, this is a form of radionuclide imaging. When coupled with an electrocardiogram (ECG) test, it allows physicians to see how the heart functions at specific portions of the cardiac cycle. This is called a gated SPECT test. Because this test also measures the health of the heart muscle itself (by assessing how much blood the muscle absorbs), it can be helpful in certain situations when the health of the heart muscle is in question, such as after a heart attack.
  
  
• Nuclear stress test. An exercise stress test performed before and after the administration of a radionuclide tracer (gated SPECT). It creates images of the heart before, during and after physical exertion. Therefore, an ejection fraction may be obtained at both rest and during exercise. This approach offers a very sensitive way to identify heart pump function.
  
  
• Cardiac magnetic resonance imaging (MRI). A test that uses powerful magnets to visualize the heart’s structure. This test has very good resolution, but the patient is required to hold their breath during the test, a feat that may be difficult for patients with heart failure. Also, because this is newly adapted technology to measuring ejection fraction, it remains an expensive test that requires specialized training.
  
  
• Computed tomography (CT) scan. This test uses x-ray scans that are detected by multiple sensors and then collated by computer into a three-dimensional image. Newer CT scanners have up to 64 scanners, allowing for very detailed images of the heart. However, because of the relatively high radiation exposure associated with this test, it's unlikely to be used for routine screening or evaluation unless the test is already being conducted for another reason.