Abstract

*Akio Ogura PhD, Toru Takemura and Yui Taguchi

ABSTRACT

Purpose: Fiber tracking is a method that uses diffusion tensor magnetic resonance imaging (DTI) to depict nerves by measuring the strength and anisotropic direction of each voxel. The imaging parameters used in DTI analysis are important, but the degree to which individual parameters affect nerve depiction has not been studied. The purpose of this study was to compare the depiction of nerve fibers of the corticospinal tract using different DTI parameters. Materials and Methods: DTI scans of the human brain were analyzed using four different imaging parameters: voxel size, number of excitations (NEX), number of motion probing gradient (MPG) directions, and b-values. The pyramidal depictions of tractography using these imaging parameters were compared using a 1.5 T magnetic resonance imaging device. For each image, the bilateral corticospinal tracts were modeled by fiber tractography using each of the aforementioned parameters. The resulting tractographies were assessed by physical and visual evaluation to measure the effect of the parameters under investigation. Results: The number and length of fibers increased significantly with an increase in the voxel size. However, there was no significant change in the length and number by the b-value, number of MPG axes, or NEX. The visual evaluation score also increased significantly with an increase in the voxel size. Conclusion: An increased voxel size significantly improved the depiction of corticospinal tract nerves in DTI tractography.