purpose of MRA brain scan
Guide. Magnetic resonance imaging (MRI) is a test that uses a magnetic field and pulses of radio wave energy to take pictures of the head. In many cases, MRI gives information that can't be seen on an X-ray, ultrasound, or computed tomography (CT) scan. Problems with blood vessels may include an aneurysm or abnormal twisted blood vessels that are present at birth (this is called an arteriovenous [AV] malformation). 2  Check blood flow or blood clots to the brain. 3  MRI can show bleeding in or around the brain. 4  Check symptoms of a known or suspected head injury.