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 noninvasive.
MRA; Angiography - magnetic resonance
How the test is performed
You may be asked to wear a hospital gown or clothing without metal fasteners (such as sweatpants and a t-shirt). Certain types of metal can cause blurry images.
You will lie on a narrow table, which slides into a large tunnel-shaped scanner.
Some exams require a special dye (contrast). The dye is usually given before the test through a vein (IV) in your hand or forearm. The dye helps the radiologist see certain areas more clearly.
During the MRI, the person who operates the machine will watch you from another room. The test may take 1 hour or more.
How to prepare for the test
You may be asked not to eat or drink anything for 4 - 6 hours before the scan.
Tell your doctor if you are afraid of close spaces (have claustrophobia). You may be given a medicine to help you feel sleepy and less anxious, or your doctor may suggest an "open" MRI, in which the machine is not as close to the body.
Before the test, tell your health care provider if you have:
Brain aneurysm clips
Artificial heart valve
Heart defibrillator or pacemaker
Inner ear (cochlear) implants
Insulin or chemotherapy port
Intrauterine device (IUD)
Kidney disease or dialysis (you may not be able to receive contrast)
Renal artery stenosis (narrowing of the blood vessels in the kidneys)
A normal result means the blood vessels do not show any signs of narrowing or blockage.
What abnormal results mean
An abnormal exam suggests 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. It uses no radiation. To date, no side effects from the magnetic fields and radio waves have been reported.
The most common type of contrast (dye) used contains gadolinium. It is very safe. Allergic reactions to the substance rarely occur. However, gadolinium can be harmful to patients with kidney problems who require dialysis. If you have kidney problems, please tell your health care provider before the test.
The strong magnetic fields created during an MRI can cause heart pacemakers and other implants to not work as well. It can also cause a piece of metal inside your body to move or shift.
Pennell D. Cardiovascular magnetic resonance imaging. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. St. Louis, Mo: WB Saunders; 2007:chap 17.
Jackson J, Allison DJ, Meaney J. Angiography: principles, techniques, and complications. In: Grainger RC, Allison D, Adam A, Dixon AK, eds. Diagnostic Radiology: A Textbook of Medical Imaging. 5th ed. New York, NY: Churchill Livingstone; 2008:chap 6.
Ken Levin, MD, private practice specializing in Radiology and Nuclear Medicine, Allentown, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.