When magnetic resonance imaging (MRI) is used to diagnose problems in the blood vessels, the test is often called a magnetic resonance angiogram (MRA). MRA is a type of imaging; that is, it creates images of the blood vessels so a physician can identify problems.
How Does It Work?
An MRA uses magnetic fields and radio waves to produce two- or three-dimensional images of blood vessels. These images provide doctors a more precise assessment of the severity and location of any blockages in the arteries.
How Is It Performed?
For the MRA, you will go to a special laboratory, change into a gown and remove all jewelry and other metal objects. You may be given medications to help you lie still during the MRA, which typically takes 30 to 90 minutes.
To prepare for the MRA, you will be asked to lie on a table. A technician will then slide the table into a hollow, donut-shaped chamber. There you will be exposed to magnetic fields and radio waves - both harmless and painless. If requested by your doctor, a small amount of "dye" will be injected through an IV in your vein. This contrast dye makes it easier for the physician to see your blood vessels. Lying still on the table in an enclosed area may be the most uncomfortable aspect of the MRA. If you feel uncomfortable in closed spaces, your doctor can administer anxiety-reducing medication at your request. Some hospitals use an “open MRI” instead of a “closed” one. You will also find that the scanner makes many loud "clanking" noises during the test.
Is it Safe?
If you have a pacemaker, defibrillator, prosthetic joint, certain types of stents, surgical clips, mechanical heart valve or other metallic devices in your body, you might not be eligible to undergo an MRA. Whether you are depends on the type of metallic device. If you have tattooed eyeliner, let your physician know before the test, as tattoos contain metal that can be pulled by the magnetic field, which poses a risk that close to your eyes. Your doctor can tell you if an MRA is safe for you.
MRA is considered safe. However, people have been harmed if metal is in their body or in the room. Be sure to tell your physician if you have metal implants, and remove all metal from your body before the test. In addition, you cannot have a "dye" injection for the MRA if you have a known allergy to MRI contrast (gadolinium). The contrast dye used in MRA does not present a problem for people with an iodine allergy. If you have kidney failure, talk with your doctor.
Questions to Ask Your Doctor About MRA
The following questions can help you talk to your physician about having an MRA. Consider printing out or writing down these questions and taking them with you to your appointment. Taking notes can help you remember your physician’s response when you get home.
- What information will an MRA give us about the health of my blood vessels?
- Why is an MRA being recommended? (That is, what symptom or test result needs further exploration?)
- What are the potential benefits for me of an MRA?
- What are my individual risks from an MRA?
- If I have an implanted metallic device, is an MRA safe for me?
- What happens next if an MRA indicates that I have a problem with a blood vessel?
Please print this list of questions here. Take them with you to the doctor and share them with friends and loved ones when you are encouraging them to see their doctors.