
Kinematic MRI Views Physiologic Changes in Spinal Cord
Cervical spondylitic myelopathy, a disease of the spinal cord caused by changes in the shape of the vertebral body, is the most common disease of the spinal cord among middle-aged people.
Extension and hyperextension of the neck are considered significant movements which contribute to cervical myelopathy, although some have suggested that flexion also plays a role.
The cervical spines of 40 healthy individuals were examined in a whole-body magnetic resonance scanner to determine the functional changes in the cervical cord and the subarachnoid space that occur during flexion and extension. At flexion, a narrowing of the ventral subarachnoid space of up to 43% and a widening of the dorsal subarachnoid space of up to 89% were observed. At extension, an increase in the diameter of the ventral subarachnoid space of up to 9% was observed, whereas the dorsal subarachnoid space was reduced to 17%. At flexion, there was a reduction in the sagittal diameter of the cervical cord of up to 14%, and at extension, an increase of up to 15%.
Conclusion: Compared with functional cervical myelograms, kinematic magnetic resonance imaging can provide additional noninvasive data concerning the physiologic changes in the cervical subarachnoid space and the cervical cord during flexion and extension.

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