This is an abbreviated version of the complete article.*
Magnetic resonance angiography (MRA) is a form of magnetic resonance imaging (MRI) that uses radio waves and a magnetic field to noninvasively and painlessly show the structure of blood vessels and the blood flow within the blood vessels.
MRA can reveal the narrowing of blood vessels, any blockages affecting them, and other vascular abnormalities such as aneurysms (bulges in the blood vessels).
Physicians may use MRA to get information that is similar to information from an invasive angiography procedure.
Magnetic resonance angiography, or MRA, is a form of magnetic resonance imaging (MRI) that, like MRI, uses radiowaves and magnetic fields to create images of the organs and tissues inside the body. MRA also shows blood flow through vessels. The test can reveal aneurysms, vessel narrowing (stenosis), and obstructions such as clots, helping physicians diagnose and treat vascular disease.
MRA is typically not the first test that physicians use to diagnose vascular disease. After using blood pressure measurements, CT scans, and ultrasound to screen for disease, physicians may turn to MRA to determine the severity of disease.
MRA has not yet supplanted contrast angiography, the standard test for evaluating blood vessels before determining treatment. However, MRA is gaining ground on contrast angiography because of the latter test's possible complications.
Typically, there is no preparation. Occasionally, some patients are asked to fast for 4 to 6 hours before the test.
All patients should alert physicians to any implanted metallic devices such as pacemakers, artificial heart valves, joint and bone clips, and even bullets they might have that could interfere with the MRA's results.
Patients who may be unsuited for MRA include:
Those who suffer from claustrophobia;
Pregnant women; and
People with implanted metal devices.
WHAT TO EXPECT
An MRA lasts between 30 to 90 minutes.
A technologist will ask the patient to change into a hospital gown and remove any jewelry or wristwatch. The patient then lies on the MRA table.
Because MRA images can become blurred with motion, the technologist may offer the patient a sedative. He or she may also offer ear plugs to insulate the patient from the noise of the MRA machine.
In some centers, a contrast liquid is injected into the veins to improve the images.
The MRA table automatically slides through a hollow, donut-shaped chamber that exposes the patient to a magnetic field and pulses of radiowaves. This exposure is painless but may cause some patients to feel a mild tingling in any dental fillings.
If patients receive a sedative for the MRA, they will need to arrange a ride home. Otherwise, patients can resume normal activities immediately.
Medical Review Date: June 21, 2004
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