A magnetic resonance angiogram (MRA) is a type of magnetic resonance image (MRI) scan that uses a magnetic field and pulses of radio wave energy to provide pictures of blood vessels inside the body. In many cases, MRA can provide information that cannot be obtained from an X-ray, ultrasound, or computed tomography (CT) scan.

MRA can find problems with the blood vessels that may be causing reduced blood flow. With MRA, both the blood flow and the condition of the blood vessel walls can be seen. The test is often used to look at the blood vessels that go to the brain, kidneys, and legs. Information from an MRA can be saved and stored on a computer for further study. Photographs of selected views can also be made. See an illustration of an MRA.

During MRA, the area of the body being studied is placed inside an MRI machine. Contrast material is often used during MRA to make blood vessels show up more clearly.

Why It Is Done

A magnetic resonance angiogram (MRA) is done to look for:

• A bulge (aneurysm), clot, or the buildup of fat and calcium deposits (stenosis caused by plaque) in the blood vessels leading to the brain.
• Narrowing (stenosis) of the blood vessels leading to the lungs, kidneys, or legs.

How To Prepare

Before a magnetic resonance angiogram (MRA), tell your doctor and the MRI technologist if you:

• Are allergic to any medicines. The contrast material used for MRA does not contain iodine. If you know that you are allergic to the contrast material used for MRA, tell your doctor before having another test.
• Are or might be pregnant.
• Have a pacemaker, artificial limb, any metal pins or metal parts in your body (especially in your eyes), metal heart valves, metal clips in your brain, metal implants in your ear, tattooed eyeliner, or any other implanted or prosthetic medical device (such as a medicine infusion pump). Also, tell your doctor if you have worked around metal or if you have recently had surgery on a blood vessel. In some cases you may not be able to have the MRI test.
• Have an intrauterine device (IUD) in place. An IUD may prevent you from having the MRA test done.
• Become very nervous in small spaces. You need to lie very still inside the MRI machine, so you may need to have the test done with open MRI equipment. It is not as confining as standard MRI machines. You may need medicine to help you relax. Some blood vessels may not be seen clearly with an open MRI scanner.
• Have any other health conditions, such as kidney problems or sickle cell anemia, that may prevent you from having an MRA using contrast material.
• Wear any medication patches. The MRI may cause a burn at the patch site.