How It Is Done
A magnetic resonance imaging (MRI) test is done by an MRI
technologist. The pictures are read by a
radiologist. However, some other types of doctors
(such as a
neurologist or
neurosurgeon) can also read an MRI scan of the
head.
You will need to remove all metal objects (such as hearing aids,
dentures, jewelry, watches, and hairpins) from your body because these objects
may be attracted to the powerful magnet used for the test. If you have had an
accident or you work around metal, there is a chance that you have metal pieces
in your head, eyes, skin, or spine. An X-ray may be taken before the MRI to see
if you can have the test.
You may need to take off some of your clothes. You will be given a
gown to wear during the test. If you keep your clothes on, empty your pockets
of any coins and cards (such as credit cards or ATM cards) with scanner strips
on them because the MRI magnet may erase the information on the cards.
During the test you will lie on your back on a table that is part
of the MRI scanner. Your head, chest, and arms may be held with straps to help
you lie still. The table will slide into the space with the magnet. A device
called a coil may be placed over or wrapped around your head. Some MRI machines
(called open MRI) are now made so that the magnet is not around your whole
body.
Some people feel nervous (claustrophobic) inside the MRI magnet. If
this keeps you from lying still, you can be given a medicine (sedative) to help
you relax. Open MRI machines may be helpful if you are claustrophobic.
Inside the scanner you will hear a fan and feel air moving. You may
also hear tapping or snapping noises as the MRI pictures are taken. This is
normal. You may be given earplugs or headphones with music to reduce the noise.
It is very important to hold completely still while the scan is being done. You
may be asked to hold your breath for short periods of time.
During the test, you may be alone in the scanner room. The
technologist will watch you through a window. You will be able to talk through
a speaker.
If contrast material is needed, the technologist will put it in an
intravenous (IV) line in a vein in your arm. The
material may be given over 1 to 2 minutes. Then more MRI scans are done.
An MRI test usually takes 30 to 60 minutes but can take as long as
2 hours.