Tract-Specific Diffusion Tensor Imaging in Cervical Spondylotic Myelopathy Before and After Decompressive Spinal Surgery: Preliminary Results.

Purpose: Diffusion tensor imaging (DTI) metrics of the cervical spinal cord in patients with cervical spondylotic myelopathy (CSM) were compared to those measured in healthy volunteers, using tract-specific region of interests (ROIs) across all cervical intervertebral disc levels.

Methods: Magnetic resonance (MR) imaging of the cervical spinal cord was performed in four patients with CSM and in five healthy volunteers on a 3-T MR scanner. Region-specific fractional anisotropy (FA) and mean diffusivity (MD) were calculated on axial imaging with ROI placement in the anterior, lateral, and posterior regions of the spinal cord. FA and MD were also calculated on sagittal acquisitions. Nonparametric statistical tests were used to compare controls and patients before and after surgery.

Results: FA values were significantly lower (p = 0.050) and MD values were significantly higher (p = 0.014) in CSM patients measured at level of maximal compression before surgery than in healthy controls in lateral and posterior ROIs, respectively. In posterior ROIs, MD values were significantly higher in patients before surgery compared to controls at all levels except C7-T1.

Conclusion: Patients with CSM may demonstrate region-specific changes in DTI metrics when compared to healthy controls. Changes in DTI metrics may also occur at levels remote from site of compression.