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|What is an MRI?
Magnetic resonance imaging or MRI
is defined by the American College of Radiology as one of the newest and
most exciting fields of medical imaging. The MRI produces an image that
is like a visual "slice" of anatomy and is capable of generating an infinite
number of images throughout the body.
During an MRI, a large magnet, with a magnetic
field 60,000 times greater than the earth's magnetic field, surrounds the patient.
Radio frequencies and a computer are used to produce the images.
The body is made of particles called atoms.
The center of the atom are nuclei that normally spin at different angles.
When the magnetic field hits the nuclei, they begin to spin at the same
angle. A radio signal, which temporarily changes the nuclei alignment,
is sent out. When the signal is stopped, the nuclei return to the aligned
position and release a faint radio frequency of their own. The frequency
is recorded by the computer and processed into a detailed image of the
Using MRI, physicians can see the brain
and tiny nerves that makeup the spinal cord. Because of this clarity, the
MRI is often used to examine the brain, neck, and spinal cord.
Patients with cardiac pacemakers, metallic
clips in the brain and other metallic foreign bodies in the eye area cannot
undergo an MRI.