Quantitative assessment of column-specific degeneration in cervical spondylotic myelopathy based on diffusion tensor tractography.

PURPOSE: Cervical spondylotic myelopathy (CSM) is a common spinal cord disorder in the elderly. Diffusion tensor imaging (DTI) has been shown to be of great value for evaluating the microstructure of nerve tracts in the spinal cord. Currently, the quantitative assessment of the degeneration on the specific tracts in CSM is still rare. The aim of the present study was to use tractography-based quantification to investigate the column-specific degeneration in CSM. METHODS: A total of 43 volunteers were recruited with written informed consent, including 20 healthy subjects and 23 CSM patients. Diffusion MRI was taken by 3T MRI scanner. Fiber tractography was performed using TrackVis to reconstruct the white matter tracts of the anterior, lateral and posterior column on the bilateral sides. The DTI metrics acquired from tractography, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD), were compared between healthy subjects and CSM patients. RESULTS: Compared to healthy subjects, FA was found significantly lower in the lateral (Healthy 0.64 ± 0.07 vs. CSM 0.53 ± 0.08) and posterior column (Healthy 0.67 ± 0.08 vs. CSM 0.47 ± 0.08) (p < 0.001), while MD, AD and RD were significantly higher in the anterior, lateral and posterior column in CSM (p < 0.05). CONCLUSION: Loss of microstructural integrity was detected in the lateral and posterior column in CSM. Tractography-based quantification was capable of evaluating the subtle pathological insult within white matter on a column-specific basis, which exhibited potential clinical value for in vivo evaluation of the severity of CSM.

Normal values of cervical spinal cord diffusion tensor in young and middle-aged healthy Chinese.

PURPOSE: Lack of normal reference value of diffusion tensor imaging parameters hinders its application in clinical practice. In this study, we aim to establish a comprehensive normal DTI database of Chinese subjects. METHODS: Sixty-five healthy subjects aged 21-61 years were recruited and underwent 3T DTI scan of cervical spine. DTI parameters were measured in whole cord, ventral, lateral and dorsal column from C2 to C7 segments. Regions, segments, gender and age-related changes of DTI parameters were analyzed. RESULTS: No significant difference was found between genders (p > 0.05). DTI parameters significantly differed among different cord levels (p < 0.05). FA value in whole cord, grey matter, dorsal and ventral column showed significant but weak correlation with age (p < 0.05). CONCLUSION: A comprehensive normal database of DTI parameters of cervical spinal cord was established. The effect of gender and age-related changes is negligible in DTI analysis of cervical spinal cord disorders.