Definition: The type of Magnetic Resonance Imaging (MRI) that is used to visualize the arteries that bring blood to the body's internal organs. The MRA uses the same machine as an MRI, but a special computer software allows it to only extract generated-by-blood images, as it flows through the arteries. These images give doctors a rough idea of whether arteries are affected by disease processes, such as atherosclerosis, or dissection.
Unlike other tests used to visualize arteries, this test does not require the injection of contrast or expose people to X-ray radiation.

