MRA (Magnetic Resonance Angiography)

Medically Reviewed by Shruthi N, MD on September 25, 2024
Written by Marijke Vroomen Durning, RN
8 min read

An MRA is an imaging test that lets your doctor see inside your blood vessels -- your arteries and veins. MRA stands for magnetic resonance angiogram or magnetic resonance angiography. It’s a type of magnetic resonance imaging, or MRI. Instead of using radiation, like with X-rays and computed tomography (CT) scans, MRAs use powerful magnets, radio waves, and a computer to make images. MRAs are specific for looking at your blood vessels and blood flow.

 

MRAs can check the blood vessels in many different parts of your body:

Your doctor may order this exam for different reasons that include:

  • Checking for aneurysms or weakened blood vessels
  • Finding plaque that blocks or narrows blood vessels
  • Looking for narrowing of the aorta
  • Detecting arteriovenous malformation in the brain or elsewhere in the body
  • Looking for problems with the structure of your blood vessels
  • Screening for heart disease if you have a family history of it
  • Helping to prepare for surgery or check results after surgery
  • Finding injured blood vessels after an accident or trauma
  • Helping with cancer treatment, such as checking a tumor’s blood vessels before chemoembolization
  • Diagnosing blood clots
  • Helping doctors repair blood vessels while inserting a stent, or checking the stent placement afterward

These investigations can help diagnose aneurysms, strokes, heart disease, stenosis, and more.

MRA vs. MRI

MRI machines were invented in the mid-to-late 1900s when scientists found a way to use magnets and radio waves to make images. When you undergo an MRI, your doctor can see detailed images of your organs and body structures, including bones and muscles. 

Not long later, researchers developed the MRA machines because while MRIs could give images of solid structures in your body, you couldn’t see inside blood vessels. Now, with an MRA, along with seeing the inside of the blood vessels, your doctor can determine how fast your blood is flowing. 

You will get instructions, usually from the place where you’ll have your MRA. Make sure you understand the directions and follow them closely. They may include information about:

  • Whether you can eat or drink before the test
  • If it’s OK to take your usual medicines
  • What you may wear and what you will need to take off

The MRA equipment includes a magnetic field. So you’ll need to take off anything metal, such as:

Make sure you tell your doctor or the staff at the MRA facility if you:

  • Have medical problems, like kidney disease
  • Are allergic to anything
  • Are pregnant or breastfeeding
  • Have any medical devices or implants, like heart valves, drug ports, artificial limbs or joints, metal pins, screws, plates, staples, or stents

Also let them know if you have other metal:

  • Left from an accident or injury
  • In some tattoo dye
  • From dental work

MRA is safe for people with most types of metal implants, except:

  • Some cardiac defibrillators
  • Some pacemakers
  • Cochlear or ear implants
  • Some clips for brain aneurysm repair
  • Some coils for blood vessel repair

Tell your doctor, too, if you’re afraid of closed or small spaces. They may give you medicine before the test to help you relax. If so, you’ll need someone to drive you home after the exam.

When undergoing an MRA, you must lie still during the test. Some people find the machine claustrophobic or the idea of lying still like that stressful. If you’re anxious or feel that staying still may be too difficult, ask if you can have a sedative before the test. Remember though, if you take a sedative, you’ll need someone to take you home.

Before you enter the MRA room, you’ll change into a gown and remove anything metal, including hearing aids, dentures, jewelry, and piercings. If you wear a bra, you will be asked to remove that in case there is underwire or metal in the hooks. 

If you wear a medication patch (for pain, smoking cessation, etc.), check if you need to remove that as well. Sometimes the machines can cause burns where the patches are.

Once you’re ready, you’ll be asked to lie on an exam table that slides into a large circular area, the magnetic field. The actual equipment may be different depending on where you get the test done. Some types allow little room to move. Newer designs have more room or open sides. The technologist will help you get into the correct position to start the test.

You will have to stay still during the test and may be asked to hold your breath at times. During the MRA, you and the technologist will be able to talk to each other. The equipment makes very loud tapping or pounding noises, so you may wear ear plugs or headphones to help soften the sounds.

The technologist will take several images. For some exams, you will get a special dye injected into a vein. It helps to make the images even clearer and more detailed.

This type of dye usually doesn’t cause allergic reactions, unlike some that contain iodine. However, if you have kidney failure, be sure to mention this because the dye could cause a rare condition called nephrogenic systemic fibrosis.

Is an MRA exam painful?

The MRA exam itself isn’t painful. You can’t feel the radio waves or magnets. However, some people do feel sore from having to stay still in the same position on their back until the test is done. If you have an IV for contrast, the IV site – where the catheter is in the vein – may be uncomfortable too.

When you are done, the technologist will return to the exam room and slide you out of the scanner. They will remove the IV if you had dye for your test.

Unless you had medicine to help you relax, you can usually get back to your normal activities. If you had the medicine , then you may need to rest. You won’t be able to drive until it wears off.

Your doctor will call you with the results of the exam. You may have more tests, depending on the findings.

A radiologist, a doctor who specializes in reading images, will examine the images and write a report. This is then sent to your doctor. The results will say if they noticed anything unusual and if so, what they saw. For example, if you are being tested to see if you have any plaques that may narrow your blood vessels, the report will say where and how much of a blockage there is.

If it’s an emergency, a radiologist will look at the images as soon as possible.

MRA tests are quite safe for most people. They don’t use radiation, so there’s no radiation risk. Possible side effects, if any, are usually because of the contrast dye, but they are rare. They include:

  • Headache
  • Upset stomach
  • Allergic reactions

If you need a sedative, there is also a risk there, as there is with all medications. Be sure to follow the prescription label as indicated and have someone escort you home afterward.

Special considerations include:

If you are breastfeeding. If you get a contrast dye and are breastfeeding, you might have to stop breastfeeding for at least a day. Ask your doctor because different dyes have different recommendations and some experts say that you don’t have to stop. If you do stop breastfeeding for 24 to 48 hours, you can “pump and dump” to keep your supply constant. 

If you have kidney disease. The contrast dye is removed from your body through your kidneys. If you have problems with your kidneys, your doctor should check your kidney function before recommending an MRA with contrast dye.

MRA images allow your doctor to see your blood vessels and blockages, but not as clearly as another procedure called a catheter angiography. It also cannot see smaller blood vessels as well as larger ones. 

Other limitations related to having an MRA are related to having the procedure itself. For example:

  • Lying still for long periods, especially if you have pain or are anxious, can be hard, resulting in poor quality images.
  • Taking deep breaths and holding them can be difficult for some people, also making it harder to get good images.
  • Claustrophobia or anxiety can make it too stressful to stay in the MRA machine.
  • If you are over the weight limit for the machine, you may not be able to have the test.
  • Implants in your body might make it impossible to get a clear image and the implants themselves might malfunction.
  • If you have a very irregular heartbeat, this might affect how clear the images are.

MRAs are a type of magnetic resonance imaging (MRI) test that can provide detailed images of your blood vessels. These images can help your doctor find problems like narrowed blood vessels, diagnose blood clots and strokes, and look for abnormalities, among other things. The advantage to MRAs is they don’t use radiation, unlike X-rays and CT scans. But if you are going to have an MRA with a dye contrast, be sure to tell your doctor if you have any kidney problems. The dye leaves your body through your kidneys, so your doctor will have to check your kidney function beforehand. 

What is the difference between an MRA and a CT scan?

An MRA uses magnetic fields, radio waves, and computers to form an image that your doctor can see on a screen. A CT scan uses radiation to make the images.

Can an MRA test show brain damage?

An MRA test can show if there are blockages or abnormalities in the blood vessels in your brain.

How long do MRA test results take?

If it is an emergency test, a radiologist, a doctor who specializes in reviewing imaging studies, can look at the images right away and discuss the results with your doctor. Typically though, the radiologist will review the scan results within a few days and send their report to your doctor.

Will an MRA test show a stroke?

An MRA test can show if there is a blockage in a blood vessel in your brain that could have caused a stroke.

Is an MRA exam safe in children?

Yes, MRAs are safe for children. But infants and younger children usually can’t lie still in the machine, so they would likely need some sedation.
 

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