WHAT IS AN MRI?
A non-invasive procedure that uses magnets and radio waves to produce a picture of
the inside of the body area under investigation. Magnetic resonance imaging (MRI) produces
pictures of the inside of the body area under investigation without exposing the body to
ionizing radiation (X-rays). The MRI scanner creates a strong magnetic field, which
causes the atoms within body tissues to align. A radio wave is directed at the body,
triggering the atoms within body cavity tissues to emit radio waves of their own.
This returned radio wave creates a signal (resonance) that is detected by the scanner
at thousands of angles around the body. The scanner sends the signals to a computer,
which processes the information and compiles it into a 3-dimensional image of the
tissue being scanned. Any 2-dimensional "slice" can be projected as a visual image,
which can be stored on photographic film or videotape. MRI scans can see through bone
and provide clear, detailed pictures of soft tissues.
HOW IS THE MRI PERFORMED?
The MRI scanner is in an area that has been shielded from outside magnetic fields.
You are asked to lie on a narrow table that can slide inside a tunnel-like tube
within the scanner. The scanner creates a magnetic field around you, then pulses
radio waves that are directed at the tissues in question. Several sets of images
are usually required, each taking from 2 to 15 minutes. The complete scan takes
about 1/2 hour; some scans may take more than one hour.
HOW CAN I PREPARE FOR AN MRI?
No preparatory tests, diets, or medications are usually needed. Occasionally,
the person may be asked to fast for 4 to 6 hours prior to the scan. You must sign
a consent form. Because of the strong magnets, no metallic objects are allowed
into the room. Items such as jewelry, watches, credit cards, and hearing aids
can be damaged. Pins, hairpins, metal zippers, and similar metallic items can
distort the images. Frequent exposure to ferrous metals (such as a sheet metal
worker has) may require clearance film before the MRI. A hospital gown may be
recommended, or you may be allowed to wear "sweats" or similar clothing without
metal fasteners. Removable dental work should be taken out just prior to the scan.
WHAT WILL THE MRI FEEL LIKE?
There is no pain. The magnetic field and radio waves are not felt. The primary discomfort
is the claustrophobic feeling that some people experience from being inside the scanner.
The table may be hard or cold, but you can request a blanket or pillow. The machine
produces loud thumping and humming noises. Ear plugs are usually given to reduce the
noise. A technologist observes you during the entire procedure and may enter the room
to speak to you or may speak with you through an intercom in the scanner. Excessive
movement can blur MRI images. If you have difficulty lying still or are very anxious,
you may be given a sedative. There is no recovery required (unless you have been sedated).
After an MRI scan, you can resume normal diet, activity, and medications.
HOW CAN I SCHEDULE AN APPOINTMENT?
A physicians prescription is necessary to obtain an MRI. An appointment can be made by calling the radiology department at 268-2283.
For further information about MRI Radiology at Memorial Hospital, call 570-268-2283.