Test Overview
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 cannot be seen on an
X-ray,
ultrasound, or
computed tomography (CT) scan.
For an MRI test, you lie with your head inside a special machine
(scanner) that has a strong magnet. The MRI can show tissue damage or disease,
such as infection, inflammation, or a tumor. Information from an MRI can be
saved and stored on a computer for more study. Photographs or films of certain
views can also be made. See MRI images of a person who has had a
stroke
or a
seizure
.
In some cases, a dye (contrast
material) may be used during the MRI to show pictures of structures more
clearly. The dye may help show blood flow, look for some types of tumors, and
show areas of inflammation.
MRI of the head may be used to look for the cause of headaches. For
more information, see:
Should I have imaging tests to look for the
cause of my headaches?
See pictures of
a standard
MRI machine
and
an open
MRI machine
.