How It Is Done
A magnetic resonance imaging (MRI) test is usually done by an MRI
technologist. The resulting pictures are usually interpreted by a
radiologist. However, some other types of doctors,
such as an
orthopedic surgeon, can also interpret a shoulder MRI
scan.
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.
You will need to take off all or most of your clothes, depending on
which area is examined (you may be allowed to keep on your underwear if it is
not in the way). You will be given a gown to use during the test. If you are
allowed to keep some of your clothes on, you should 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. The table will slide into the space that contains the
magnet. A device called a coil may be placed over or wrapped around the area to
be scanned.
Some people feel nervous (claustrophobic) inside the MRI magnet. If
feeling nervous keeps you from lying still, you can be given a medicine
(sedative) to help you relax. Some MRI machines (called open MRI) are made so
that the magnet does not enclose your entire body. 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 scans are taken. 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. However, the
technologist will watch you through a window. You will be able to talk with the
technologist through a two-way intercom.
If contrast material is needed, the
technologist will put it in an IV in your arm. The
injection may be given over 1 to 2 minutes.
Contrast material may be put directly into your shoulder joint by
the radiologist. Your doctor will make your shoulder numb (local anesthetic) before putting in the contrast
material. Then more MRI scans are done for this part of the test. This is
called a magnetic resonance arthrogram.
An MRI test usually takes 30 to 60 minutes but can take as long as
2 hours.