MRA of the Legs: About This Test

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Artery in leg narrowed with plaque

What is it?

MRA (magnetic resonance angiogram) is a type of magnetic resonance imaging (MRI) scan that uses a magnetic field and pulses of radio wave energy to provide pictures of blood vessels inside the body. A standard MRI cannot provide a good picture of the blood vessels and blood flow.

When you have an MRA, you lie on a table and the table moves into the MRI machine. An MRA is done with the same machine as an MRI.

Why is this test done?

An MRA of the legs is done to look at the blood vessels in the legs. It checks for narrowing (stenosis) and blockage of the arteries. Narrowing of the arteries is called peripheral arterial disease. The test can also be used to help a surgeon prepare for surgery on the arteries of the pelvis and legs.

How can you prepare for the test?

  • Do not use tobacco products or eat or drink (including alcohol or caffeinated beverages) for 2 hours before the test.
  • Do not take iron supplements on the day of the test.
  • Talk to your doctor about all your health conditions before the test. For example, tell your doctor if:
    • You are allergic to any medicines.
    • You are or might be pregnant.
    • You have a pacemaker, an artificial limb, any metal pins or metal parts in your body, metal heart valves, metal clips in your brain, metal implants in your ears, or any other implanted or prosthetic medical device.
    • You have an intrauterine device (IUD) in place.
    • You get nervous in confined spaces. You may need medicine to help you relax.
    • You wear any patches that contain medicine.

What happens before the test?

  • You will remove all metal objects. These include hearing aids, dentures, jewellery, watches, and hairpins.
  • You may need to take off some of your clothes. You will be given a gown to wear during the test. If you do leave some clothes on, make sure you take everything out of your pockets.
  • You will probably have contrast material (dye) put into your arm through a tube called an IV. Contrast material helps doctors see specific organs, blood vessels, and most tumours.

What happens during the test?

  • You will lie on your back on a table that is part of the MRI scanner. Your head, chest, and arms may be held with straps to help you remain still.
  • The table will slide into the space that contains the magnet. A device called a coil may be placed around or on your legs.
  • Inside the scanner you will hear a fan and feel air moving. You may hear tapping, thumping, or snapping noises. You may be given earplugs or headphones to reduce the noise.
  • You will be asked to hold still during the scan. You may be asked to hold your breath for short periods.
  • You may be alone in the scanning room, but a technologist will be watching you through a window and talking with you over an intercom during the test.

What else should you know about the test?

  • If you have kidney disease, such as kidney failure, talk to your doctor before having an MRA scan with a dye. The dye used for an MRA contains a chemical called gadolinium. If you have kidney disease, this chemical may cause a serious problem called nephrogenic systemic fibrosis.
  • An MRA does not hurt.
  • If a dye is used, you may feel a quick sting or pinch and some coolness when the IV is started. The dye maygive you a metallic taste in your mouth. Some people feel sick to their stomach or get a headache.
  • If you breastfeed and are concerned about whether the dye used in this test is safe, talk to your doctor. Mostexperts believe that very little dye passes into breast milk and even less is passed on to the baby. But if youprefer, you can store some of your breast milk ahead of time and use it for a day or two after the test.
  • You may feel warmth in the area being examined. This is normal.

How long does the test take?

  • The test usually takes 30 to 60 minutes but can take as long as 2 hours.

What happens after the test?

  • You will probably be able to go home right away, depending on the reason for the test.
  • You can go back to your usual activities right away.

When should you call for help?

Watch closely for changes in your health, and be sure to contact your doctor or nurse call line if you have any problems.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

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Current as of: November 21, 2017