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Positional Weight-bearing Mri: A Valuable Tool For Evaluating Musculoskeletal Trauma And Upper Cervical Spine Whiplash Injuries

Magnetic Resonance Imaging (MRI) is a noninvasive and radiation-free medical test conducted by physicians to look inside the human body. MRIs use powerful magnetic fields and radio signals to produce an image of the targeted body part. With review by a specially trained radiologist, images produced by an MRI can provide clear indicators of why the patient was having certain symptoms and lead to proper treatment.

The initial design of MRIs was tunnel-like where patients would lay down in a circular, enclosed tube.  Due to a large number of patients experiencing claustrophobia and a “sensation of being buried,” MRI manufacturers produced machines designed with magnets placed above and below with the sides open.  These machines are commonly known as “open MRIs.”  However, patients are still lying down with a very heavy magnet inches from their face and even though these machines do decrease the “buried” effect, many patients continued to complain of claustrophobia.

It is a simple, yet fundamental observation that many human musculoskeletal conditions are impacted by gravity, and that many patients experience signs and symptoms in weight bearing positions even when they do not in the recumbent one.  Conventional magnetic resonance imaging systems are limited to acquiring scans with patients in the recumbent position. Thus, recumbent imaging alone may not demonstrate the full degree of pathology, due to muscle and ligament relaxation and in the case of the spine, disc retraction.  Smith et al. (2006) performed a study on 25 patients with low back pain and sciatica.  These patients were referred for lumbar spine MRIs following at least one prior “normal” recumbent MRI within 6 months of referral. In this study, 13 patients demonstrated abnormalities in one or more of the seated postures that was not evident in the supine positioned MRI.  That’s a 52% missed rate.  Would you send a loved one to do mammography on a machine that missed pathology 52% of the time?

Positional MRI is a continued evolution in the design of this technology.  The magnets are vertically placed on the sides which results in a front open design virtually eliminating any claustrophobia as patients can watch television while the MRI exam is being performed.  From a medical perspective, a major advantage emerged from this front and top open design.  Patients can actually be placed in varying positions rather than “supine only” which is the limitation with other MRIs.  Unlike the traditional MRIs where the patient only had their injury imaged in a relaxed state while lying down, the Positional MRI system allows upright, angled (slanted) and recumbent imaging, replicating partial or full weight bearing conditions.  It also allows kinetic maneuvers of the patient’s whole body or any body part which results in images acquired in position of normal everyday stress, across the limits of normal range of motion. Most importantly, imaging is performed in the specific position of the patient’s clinical symptomatology.