Magnetic resonance imaging (MRI) and magnetic resonance angiograph (MRA) are tests used to produce two- or three-dimensional images of the structures inside your body, including your blood vessels. MRA does not require X-ray exposure to detect narrowing of arteries, unlike computed tomography (CT) scans or angiograms. MRA may also be used to develop your treatment plan.
Who Benefits From MRI/MRAMRA helps your physician diagnose the following conditions:
- Bulges in your aorta, called aneurysms
- Tears in your aorta, called dissections
- Narrowing of the arteries in and around your kidneys, called renal artery stenosis
- Inflammation in your blood vessels, called vasculitis
- Hardening of the arteries (called atherosclerosis) involving the legs or arms
- Blockages in the major arteries that supply blood to your brain, called carotid artery disease
You may not be eligible for an MRA if you:
- Weigh more than 300 pounds
- Have a pacemaker or other metallic devices inside your body, such as joints, pins, clips, or valves
- Are on continuous life support devices, such as oxygen
- Are pregnant
- Are claustrophobic
- Are extremely anxious, confused, or agitated and unable to lie still
Preparing for MRA
Your physician may ask you not to eat four to six hours before the test, but usually no other preparation is necessary. You will need to remove any jewelry or metallic objects that may be affected by the magnetic field. The technician can give you a sedative to make sure that you lie still during the procedure because motion can result in poor quality images.
MRA equipment consists of a table that slides in and out of a donut-shaped machine. A computer attached to the machine processes radio waves and magnetic fields to create two-dimensional or three-dimensional images.
- You will lie on the MRA table, which slowly moves through a hollow, donut-shaped chamber
- Magnetic fields and radio waves are harmless and painless
- The only discomfort that you may feel during the scan will be from lying still on the hard table in an enclosed area
- Sometimes during a MRA, the technician may inject contrast dye into your hand or forearm to improve image quality
- You can communicate with the technician though speakers in the MRA room
- Sometimes the technician may inject a contrast dye into your hand or forearm to improve the quality of the images
- An MRA lasts between 30 and 90 minutes
- If you are claustrophobic, your physician may recommend an open MRA or help you with a calming medication. This method may not be useful for all situations
After the procedure, you can expect to resume your pre-test activity, unless you required sedation during the examination. Your physician will instruct you to arrange for a ride home if you receive a sedative.
Complications from an MRA, such as a reaction to the contrast dye, are very unusual. Discuss any concerns with your physician prior to the test.