3 T magnetic resonance diffusion tensor imaging and fibre tracking in cervical myelopathy

Aim

To analyse the characterization of diffusion tensor imaging (DTI) with 3 T magnetic resonance imaging (MRI) in cervical myelopathy.

Methods

A total of 21 healthy controls and 84 patients with cervical myelopathy underwent T2-weighted imaging and DTI. The patients were divided into four groups based on the degree of cord compression and MRI signal intensity of the compressed cord as seen on T2-weighted images. The values of apparent diffusion coefficient (ADC), fractional anisotropy (FA), and eigenvalues (λ_i) were analysed, and fibre tracking (FT) was performed.

Results

For healthy controls, the mean values from the DTI of the cervical spinal cord were ADC=0.784±0.083×10⁻³mm²/s, FA=0.721±0.027, λ₁, λ₂, and λ₃=1.509±0.145×10⁻³, 0.416±0.094×10⁻³, and 0.411±0.102×10⁻³mm²/s, respectively. Only values for λ₂ and λ₃ differed significantly between the control and A groups (p<0.05). The mean values of λ₂ and λ₃ of group A were 0.516±0.105×10⁻³ and 0.525±0.129×10⁻³mm²/s, respectively. ADC, FA, λ₁, λ₂ and λ₃ differed significantly between the control and B, C, D groups (p<0.01). The FT map for group A showed a normal spinal cord, but that for groups B, C, and D showed a distorted spinal cord at the sites of compression.

Conclusion

The values of ADC, FA, and λ_i obtained with DTI could assess subtle structural damage and changes of anisotropy in the cord of cervical myelopathy. Fibre tracking was useful in verifying changes in the compressed cord.