Magnetic Resonance Angiography

What is magnetic resonance angiography?

You’ve probably heard about the test called magnetic resonance imaging or MRI. In this test, radio waves, a magnetic field, and a computer create a scan of your body parts to look for health problems.

Magnetic resonance angiography–also called a magnetic resonance angiogram or MRA–is a type of MRI that looks specifically at the body’s blood vessels. Unlike a traditional angiogram, which requires inserting a catheter into the body, magnetic resonance angiography is a far less invasive and less painful test.

During magnetic resonance angiography, you lie flat inside the magnetic resonance imaging scanner. This is a large, tunnel-like tube. In some cases, a special dye, known as contrast, may be added to your bloodstream to make your blood vessels easier to see. When needed, the contrast is given with an intravenous (IV) needle.

Why might I need magnetic resonance angiography?

If your healthcare provider believes that you may have a narrowing or blockage of blood vessels somewhere in your body, he or she may recommend magnetic resonance angiography. Other conditions that your healthcare provider can look for during this test include:

• An aneurysm or weakness in the wall of an artery
• A narrowing of the aorta, or aortic coarctation
• Bleeding in and along the wall of the aorta, or aortic dissection
• To find the cause of a stroke
• Signs of heart disease
• Narrowing or blockage of the vessels in the arms or legs
• Renal artery stenosis, a narrowing of the blood vessels in the kidneys that can lead to high blood pressure and even renal failure

What are the risks of magnetic resonance angiography?

If a dye is needed to make the blood vessels easier to see during the test, you may experience a bit of discomfort because of the insertion of the IV.

You might also experience some anxiety when placed inside the MRI scanner, which is a small, narrow space. If you think you might be claustrophobic, be sure to inform your healthcare provider of this in advance. You may be given a mild sedative to make being in the MRI scanner more bearable.

Some potential risks of magnetic resonance angiography include:

• You may suffer bodily harm from having metal objects in pockets or clothing or metal implants (such as a pacemaker or bullet fragment) within your body. Before you undergo the test, you will be asked a series of detailed questions about any metal you may have in your body.  
• If you have a problem with your kidneys, you are at risk of developing a severe reaction after receiving the MRI contrast dye that is used to make blood vessels more visible. This reaction can affect tissues throughout the entire the body including the skin, joints, liver, and lungs. If you have a history of kidney disease, your healthcare provider may decide that an MRI or MRA is not for you.

Pregnant women may have additional risks in the MRI scanner. Make sure to tell your healthcare provider if you are or might be pregnant.

You may be at risk for other complications, depending on your specific medical condition. Be sure to discuss any concerns with your healthcare provider before the test.

How do I get ready for magnetic resonance angiography?

Magnetic resonance angiography is generally regarded as a safe test, but a few precautions must be taken for your safety. These steps will also help your healthcare provider get accurate results from the test:

• Make sure to remove any watch, jewelry, coins, and other metal objects from your clothes and body. You will usually be placed in a medical gown to help with this, but don’t forget about earrings, ankle bracelets, and other jewelry.
• Tell your healthcare provider if you have any metal screws, surgical staples, bullet fragments, or other metal in your body, including a heart pacemaker, intrauterine device (IUD), implanted neurostimulator, or insulin or chemotherapy port, since these all generally contain metal components.
• You may want to ask for a blanket or a pillow to help with any discomfort during the test. The MRI scanner table is often hard and cold.
• Ear plugs are also sometimes helpful during a magnetic resonance angiogram. The machine can be quite loud as it performs the scan.

What happens during magnetic resonance angiography?

Magnetic resonance angiography may be done on an outpatient basis or during a hospital stay. Generally, magnetic resonance angiography follows this process:

1. You will remove any clothing, jewelry, or other objects that may interfere with the scan and put on a gown.
2. If you need a contrast dye to make blood vessels easier to see, this will be given through an IV.
3. You will be positioned on an exam table directly outside the MRI scanner.
4. The table will slide into position, placing you inside the MRI scanner.
5. You will need to lie still during the scanning process. Any movements can blur the images and cause the results to be less accurate.
6. The MRI scanner typically makes a lot of noise, including loud humming noises, so don’t be alarmed.
7. The full scan may take an hour or longer. This will depend on the type and number of blood vessels that your healthcare provider wishes to examine.

The scan typically causes no side effects or complications. If it is done on an outpatient basis, you are generally free to leave after the magnetic resonance angiography. Your healthcare provider will likely schedule a follow-up appointment to review the results of the test.

What happens after magnetic resonance angiography?

Your healthcare provider will examine the images from the magnetic resonance angiography. If no blockages or irregularities are found, you have what’s called a normal test result. An abnormal result means that the healthcare provider noted an abnormality in one or more of the blood vessels in your body. This may suggest that you have hardening of the arteries, known as atherosclerosis, or another circulatory problem. Your healthcare provider will likely suggest additional tests or treatments based on the specific problem that is discovered.

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