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Prior to Magnetic Resonance Imaging (MRI), the patient is instructed to remove
any metal objects (e.g. jewelry, hairpins) and change into a gown. During the
scan, the patient lies comfortably on a motorized table inside the scanner surrounded
by huge powerful magnets. The technician observes the patient throughout the
exam through large windows to the adjacent control room. The technician converses
with the patient by means of an intercom. Typically, the test takes up to an
hour to complete.
Magnetic resonance imaging does not require the patient to change
bodily positions. Instead the patient is instructed to be still. Magnetic resonance
imaging generates images in the sagittal (left/right), coronal (front/back),
axial (head/toe), and oblique (slanted) planes without moving the patient. Certain
MRI studies utilize a contrast medium to enhance particular body structures.
Magnetic resonance imaging produces vivid and complex images in 256 levels
of gray that characterizes the relationship between vertebrae, intervertebral
discs, spinal cord, and nerve roots. It is a valuable diagnostic and pre-surgical
planning tool, and replaces some invasive diagnostic procedures.
Important Considerations
If the patient's MRI scan is to include a contrast medium, known allergies
to intravenous dyes should be discussed with the referring physician prior to
the test.
Patients should tell their physician if their body contains any ferromagnetic
objects such as shrapnel, a pacemaker, or aneurysm clips. These patients cannot
undergo magnetic resonance imaging.. Ferromagnetic objects are attracted by
the MRI's powerful magnet.
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