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Open MRI vs. Closed MRI
MRI stands for magnetic resonance imaging and is a way of obtaining very detailed images of organs and tissues throughout the body without the need for x-rays. Instead, it uses a powerful main magnetic field to align protons that are found in abundance in most of the body's tissues. A second electromagnetic field, which oscillates at radio frequencies, is then pulsed to push part of the protons out of alignment. As these protons drift back into alignment with the main field, they emit a detectable radiofrequency signal. These signals are then computer-processed to create very sharp images of tissues as "slices" that can be viewed in any plane or from any direction.
Since protons in different tissues (e.g. fat vs. muscle) realign at different speeds, various structures of the body can be revealed, thus indicating whether or not injury or disease is present.
MRI is used to image every part of the body, but is particularly useful in neurological conditions, disorders of the muscles and joints, for evaluating tumors and showing abnormalities in the heart and blood vessels.
To understand the difference between an open and closed (conventional) MRI it is necessary to understand a little about how an MRI scanner works. When you are in a MRI scanner, your body generates a signal that is picked by the imaging equipment. This signal is what is used to make pictures of your body. In general, the stronger the signal, the better the pictures will look. The procedure typically lasts about 30 minutes.
Open MRI’s have gained popularity because they provide more room for the patient. This is beneficial for highly claustrophobic patients who are unable to undergo a closed MRI. A closed MRI looks like a tube. Unfortunately, this tube is somewhat narrow — which is necessary to obtain high quality images. While open MRI’s are more spacious, in most cases the image quality is not comparable to a closed MRI. This is largely due to the fact that open MRI’s are significantly weaker magnets vs. closed MRI’s. And the strength of the magnet directly relates to the quality of the images.