Upright Multi-Position MRI Used in Evaluating the Dynamic Aspects of Chiari Malformation

A new upright multi-position magnetic resonance imaging (MRI) system was recently evaluated in the diagnosis and evaluation of Chiari malformation (CM) patients.

The study, which utilized Fonar Corp.'s (Melville, NY, USA) Upright Multi-Position MRI system, was conducted by Thomas H. Milhorat, M.D., and coworkers at the Chiari Institute, North Shore-Long Island Jewish Health Systems (Great Neck, NY, USA; www.northshorelij.com) and was published in the December 2007 issue of the Journal of Neurosurgery: Spine.

The conclusion of the study was to report a previously unrecognized association between Chiari malformation type I (CM-I) and hereditary disorders of connective tissue (HDCT). The study occurred between January 2002 and April 2007 and involved 2,813 patients, of which 45% were referred for evaluation after failed Chiari malformation surgery.

The primary diagnostic tools utilized in the study were two-dimensional (2D) reconstructed computed tomography (CT) and upright X-ray radiography. The final stage of the study included examinations of patients in the Upright MRI for comparison. The investigators described, for the first time, the phenomenon of "cranial settling,” occurring in patients with both CM-1 and HDCT.

The investigators reported, "Recent experience with vertical MR imaging has proved helpful in understanding the dynamic features of occipitoatlantoaxial hypermobility. Functional cranial settling was associated with notable displacements that included reduction of the basion-dens interval, posterior gliding of the occipital condyles, anterior flexion of the occipitoatlantal joint, increased basilar impression, and cerebellar ptosis with downward displacement of the cerebellar tonsils. These displacements are consistent with the often-pronounced symptoms and signs of lower brainstem dysfunction experienced by patients with cranial settling on assumption of the upright position.”

Dr. Raymond V. Damadian, president and chairman of Fonar, said, "We are appreciative of Dr. Milhorat and his team for recognizing the Fonar Upright MRI's power to visualize the full cranial settling, cerebellar ptosis, cerebellar tonsil descent and foramen magnum impaction that occurs in the Chiari malformation-I/HDCT patients so they can be optimally addressed surgically.”

The Chiari Institute is the world's first comprehensive, multi-disciplinary center for the management of patients suffering from Chiari malformation, a rare structural condition that affects the cerebellum; syringomyelia, a chronic disease of the spinal cord; and related disorders.


Related Links:
Fonar