Magnetic Resonance Angiography (MRA)
What is Magnetic Resonance Angiography?
MRI (magnetic resonance imaging) uses magnetic fields and radio waves to produce two-dimensional or three-dimensional images of the structures inside your body, such as your brain, blood vessels, and heart. When this scanning method is applied to your blood vessels, its referred to as an MRA (magnetic resonance angiography). MRA helps your physician diagnose the following conditions:
- Hardening of the arteries in the arms or legs called atherosclerosis.
- Blockages in the major arteries that supply blood to the brain, called carotid artery stenosis.
- Bulges in your aorta called aneurysms.
- Tears in your aorta, called dissections.
- Narrowing of the arteries in and around the kidneys called renal artery stenosis.
- Inflammation in your blood vessels called vasculitis.
The MRA equipment consists of a table that slides in and out of a tube-shaped machine. A computer is attached to the machine processes radio waves and magnetic fields to create two-dimensional or three-dimensional images.
MRA not only helps your physician diagnose your condition, it also helps him or her plan treatment options. MRA also may, in some circumstances, have advantages that other tests do not. For instance, MRA does not require x-ray exposure to detect narrowing of arteries unlike computed tomography (CT) scans or standard angiograms.
How do I prepare for an MRA?
There is no preparation necessary. You do not have to fast for an MRA. If you have valuable jewelry or a watch, it is best to leave it at home before coming for the MRA.
You may not be eligible for an MRA if you:
- Weigh more than 300 pounds.
- Have a pacemaker or other metallic devices inside of the body, such as prosthetic joints, pins, clips, or valves. If you have any of these, please let your doctor know as soon as possible.
- Are on continuous life support devices such as oxygen.
- Are pregnant.
- Are claustrophobic (afraid of close spaces).
- Are extremely anxious, confused, agitated, or unable to lie still.
- If you have significant kidney disease.
If you are claustrophobic, your physician may prescribe a sedative to be taken before the procedure.
What happens during an MRA?
You will be directed to a special room where a technician will perform the test. You will be instructed to change into a hospital gown and remove jewelry or metallic objects that may be affected by the magnetic field. The technician may give you some light sedation (if it is ordered) to help you lie still during the procedure because motion can result in poor quality images.
The technician will ask you to lie on the MRA table. The table slowly slides through a tube-shaped chamber that exposes you to magnetic fields and pulses of radio waves. These magnetic fields and radio waves are painless and harmless. The only discomfort that you may feel during the scan will be from lying still on a hard table in an enclosed area. The machine also makes a loud rhythmic noise. You will be given ear plugs to block out this sound. During the test, the technician may speak to you through a speaker that is inside the MRA room. You will also need to have contrast injected through an IV in your hand or arm to improve the quality of the images. The total scan lasts from 30-90 minutes.
What can I expect after an MRA?
Unless you are given sedation, you will be able to resume pre-test activities immediately. If you received sedation, you will need to make arrangements to have someone drive you home.
Are there any complications?
Complications from an MRA, such as reaction to the contrast dye, are extremely rare.
Copyright by the
Society for Vascular Surgery