Magnetic resonance angiography (MRA) is often ordered. It gives information about the aortic arch and arch anatomy but often overestimates the degree of stenosis. This test requires administration of gadolinium. People with metallic implants, implantable cardioverter defibrillators (ICDs) and pacemakers are not candidates. MRI is also difficult for people with claustrophobia, respiratory, cardiac, and back problems due to the length of time required to be immobile in a supine position. This procedure is moderately expensive when compared to ultrasound and computerized axial tomography (CAT) scan.
Carotid angiography is less frequently done as it carries an estimated 1 to 3% risk of stroke, requires dye, which is nephrotoxic, and is expensive.