How It Is Done continued...
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 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.
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.
contrast material is needed, the technologist will put
it in an
intravenous (IV) line in a vein in your arm or hand.
The material may be given over 1 to 2 minutes. Then more MRI scans are
An MRI test usually takes 30 to 60 minutes but can take as
long as 2 hours.
How It Feels
You will not have pain from the magnetic
field or radio waves used for the MRI test. The table you lie on may feel hard
and the room may be cool. You may be tired or sore from lying in one position
for a long time.
contrast material is used, you may feel some coolness
and flushing as it is put into your IV.
In rare cases, you may
- A tingling feeling in the mouth if you have
metal dental fillings.
- Warmth in your head. This is normal. Tell
the technologist if you have nausea, vomiting, headache, dizziness, pain,
burning, or breathing problems.
There are no known harmful effects from the
strong magnetic field used for MRI. But the magnet is very powerful. The magnet
may affect pacemakers, implantable cardioverter-defibrillators (ICDs),
artificial limbs, and other medical devices that contain iron. The magnet will
stop a watch that is close to the magnet.
Metal pieces in the eyes
can damage the
retina. If you might have metal pieces in your eye, an
X-ray of the eyes may be done before the MRI. If metal is found, the MRI will
not be done.
Iron pigments in tattoos or tattooed eyeliner can
cause skin or eye irritation.