An MRI was previously named NMR, or nuclear magnetic resonance , because essentially, that is what the procedure involved, the imaging of the magnetic properties of an atom's nucleus. The term NMR is still widely used today, but is also commonly referred to as an MRI, as the word 'nuclear' tends to invoke a fear to patients of some kind of exposure to radiation.
It should be noted that there actually are imaging techniques such as various cardiovascular scans, X-Rays, or a PET (positron emission scan) that do employ the use of radioactive elements or ionizing radiation to produce an image.
So what exactly is an MRI. Not getting into a whole lot of technobabble, the MRI procedure involves laying the patient inside of an enormously powerful large magentic construct, and with the assistance of a certain low frequency radio waves, the machine scans the patient on a miniscule scale and then builds a 2 or 3-dimensional photo of the tissue region in question.
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Not everyone can be the recipient of an MRI. Because large magnetic fields are used to derive the scans and photos, people who have pacemakers or any type of metallic implant must be screened before the determination of whether or not they can receive an MRI. Anything metallic, whether inside the room or your body, will be attracted to the center of the machine at a high velocity. Also because of the radio frequency energy, very frail children and elderly run the risk of hyperthermia.
Although there is little to no evidence of deleterious effects caused by magnetic fields, pregnant women are discouraged from having MRI's performed unless deemed absolutely necessary. Also, because of the loud clicking noises that are caused by the shifting of the magnets, adequate aural protection must be taken into consideration as well.
Because of the MRI's excellent ability to distinguish between normal and abnormal tissue regions, MRI's are ideal in diagnosing a variety of different ailments. Brain tumors, bleeding or any other type of cranial damage will show up clearly on an MRI. Blood and coronary vessels that are blocked also can be located via an MRI. MRI's are used the most however when diagnosing sports related bone, joint and muscle problems.
Magnetic Resonance Imaging HowStuffWorks.com
Magnetic Resonance Imaging on Wikipedia
Magnetic Resonance Imaging on WebMD
Magnetic Resonance by Dr. Hornak MD of the Rochester Institue of Technology
MRI Unit
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MRI showing a tumor
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For educational purposes only.
