Magnetic Resonance Imaging (MRI) produces images of the body’s internal
structures by passing radio waves through a powerful magnetic field. Differing
frequencies of radio waves are produced by the different body structures,
in return, these are mapped and converted into digital images by a computer.
MRI is especially good for imaging soft tissues in the body, including
the brain, nerves, muscles and organs.
Detailed MR images allow physicians to better evaluate various parts of
the body and certain diseases that may not be assessed adequately with
other imaging methods such as X-ray, ultrasound or computed tomography
(also called CT or CAT scanning).
What to Expect
You will be lying on your back on a movable table that slides into the
center of the MRI machine. The technologist may use straps or bolsters
to help you stay still and maintain proper positioning during the examination.
He or she may place a device called a coil around the part of the body
being studied. This device sends and receives the radio waves which are
used to generate the image.
The MRI scanner is noisy. You will be given a set of earplugs or headphones
to wear during the examination to reduce the noise. It is important that
you follow the technologist's instructions. You will be asked to remain
still multiple times throughout the examination while each sequence is
being performed. Each sequence lasts between 2-10 minutes. If you are
claustrophobic (have a fear of being closed-in), you may want to discuss
the option of receiving sedation for the study with your physician prior
to your appointment. Some studies require the administration of contrast
material into the vein. MRI contrast is called gadolinium and is different
than the contrast administered for CT scans. A radiology technologist
or nurse will place an intravenous line through which he or she will give
the contrast. Most MRI examinations last between 30 to 60 minutes.
You may receive additional specific instructions when you schedule your
appointment depending upon the type of procedure that will be performed.