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Alternative names
Magnetic resonance angiography - neck; Carotid MRA; Carotid magnetic resonance angiography
Definition
Magnetic resonance angiography is an MRI exam of the blood vessels. Unlike traditional angiography that involves placing a tube (catheter) into the body, MRA is considered non-invasive.
How the test is performed
You will lie down on a narrow table, which slides into a large tunnel-like tube inside the MRI scanner. You must lie very still during the exam because movement can make the images blurry.
The MRI uses very powerful magnets and radio waves to create clear, detailed pictures of the body. Because of the strong magnets, metal objects must stay outside the room.
A complete scan may take 1 hour or more.
How to prepare for the test
You must remove all jewelry and all other metal objects, including watches, and leave them outside the exam room.
Make sure you tell the radiologist if you have any of the following:
- Metal screws, pins, plates, or staples in your body
- Heart pacemaker
- Intrauterine device (IUD)
- Any type of metal implant in the ear or eye
- Bullet fragments in the body
- Implanted neurostimulator
- Insulin or chemotherapy port
If you are pregnant, be sure to tell your doctor and radiologist before having this test.
How the test will feel
The exam is not painful. Some people may have anxiety because the scanner is very close to the body. If you are claustrophobic, tell your health care provider. You may be given a mild sedative.
The table may be hard or cold. You may wish to ask for a blanket or pillow.
The machine produces loud thumping and humming noises. Ear plugs can be used to reduce the noise.
Why the test is performed
A carotid MRA is a painless test that uses magnetic resonance angiography to create images of the insides of the two large arteries in your neck. These arteries, called carotid arteries, supply your brain with blood. You have one carotid artery on each side of your neck.
Carotid MRA shows whether a material called plaque has narrowed your carotid arteries. Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. It builds up on the insides of your arteries as you age.
Too much plaque in a carotid artery can cause a stroke. The plaque can slow down or block the flow of blood through the artery, allowing a blood clot to form. A piece of the blood clot can break off and get stuck in the artery, blocking blood flow to the brain. This is what causes a stroke.
Normal Values
A normal result shows normal blood vessels without any signs of narrowing or blockage.
What abnormal results mean
An abnormal exam shows plaque buildup in the carotid artery.
What the risks are
MR angiography is generally safe. However, people have been harmed in MRI machines when metal was in their body or a metal object was in the room. It is very important to tell your health care provider of any metal implants and to always remove all metal from your body and clothing before the test. |
