As with CLM, MR imaging is necessary to consistently diagnose syringomyelia. Myelography usually does not reveal the syrinx cavity and syringomyelia is also usually difficult or impossible to discern on CT scans. Syringomyelia appears as fluid cavitations within the spinal cord and are often multiple. It has become customary to use MR to image the brain and cervical spinal cord in dogs suspected of having CLM and syringomyelia.
Most dogs with CLM and syringomyelia have syrinx cavities throughout the thoracic and lumbar spinal cord, in addition to the cervical cord region and because of this, clinicians at the CCI prefer to have whole spine images in order to document all of the syrinx cavities in a patient. Syringomyelia is almost always a secondary phenomenon, but the causative disorder is not always CLM. Other disorders that can cause a pressure differential across the craniocervical junction can lead to syringomyelia. Such disorders include inflammatory brain disease, brain tumors , intracranial arachnoid cysts, atlantoaxial instability and atlantooccipital overlap. In addition, focal syrinx cavities can form anywhere along the length of the spinal cord if there is something near the syrinx causing turbulent CSF flow. Therefore, syringomyelia is occasionally associated with compressive intervertebral disk lesions. We have imaged some patients with focal syrinxes in which the CSF signal is focally interrupted near the site of syrinx formation; we believe that this may be evidence of tethered cord syndrome, in which the spinal cord is adhered to the meninges. Possible causes of tethered cord syndrome include inflammatory disease, trauma, and congenital anomalies.
Last Updated ( Monday, 18 October 2010 16:09 )