In vivo echo planar diffusion tensor imaging of the optic nerve in rats
Kristoffersen A, Haraldseth O, Brekken C, Vandberg T, Singstad T, Thuen M
St. Olavs Hospital HF
A protocol for in vivo echo planar diffusion tensor imaging was developed. Diffusion sensitizing gradients were applied along 12 non-collinear directions with 8 b-values in the range of 0-3000 s/mm2. The sequence was repeated 4 times, giving an acquisition time of 40 minutes. The results were high quality DTI-EPI images with few geometrical distortions, which were confirmed by manganese-enhanced MRI. Within the optic nerve, the mean diffusivity and fractional anisotropy were 1.0880.224 m2/ms and 0.7800.056, and the axial and radial diffusivities were 2.3680.447m2/ms and 0.4490.148 m2/ms. There was a statistical significant difference between the axial and radial diffusivity (p<0.001).