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Alternative names
Cranial 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
Magnetic resonance angiography (MRA) is a less-invasive alternative to traditional arteriography (angiography), which uses x-rays.
MRA is used to look at the blood vessels in the head.
It may be used to diagnose or evaluate conditions such as:
- Arterial aneurysm
- Stroke
- Blood vessel diseases
- Atherosclerosis
Normal Values
A normal result shows normal blood vessels without any signs of narrowing or blockage.
What abnormal results mean
An abnormal exam shows a problem with one or more blood vessels. This may suggest atherosclerosis, trauma, a congenital disease, or other vascular condition.
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. |
