In a traditional MRI, the patient is placed on a bed that moves inside a tube, where the MRI is done. An open MRI, an option for patients who are bothered by small spaces or are very large, does not require the patients to be placed in the tube, but is done in the "open".
MRIs are used to detect problems within the body or brain without surgery, and can identify abnormalities from outside the body.
If your physician suspects that you have a an illness or disease process, an MRI may be ordered in an attempt to identify the problem. In some cases, a diagnosis can be made with an MRI and may prevent or indicate the need for surgery.