Effects of Susceptibility Distortion and Phase Encoding Direction on Tract Consistency in Diffusion Tensor Imaging

Mustafa Okan Irfanoglu^1,2, Lindsay Walker², Carlo Pierpaoli²

The distortions on phase-encoding direction of diffusion weighted images due to magnetic susceptibility and concomitant fields greatly affect the quality and consistency of tractography using on diffusion sequences. In this work, data from a healthy population were acquired in both Right-Left and Anterior-Posterior phase encoding directions and the effects of these distortions and EPI distortion correction were analyzed on specific fiber bundles. Results indicate tracts are greatly affected by these distortions and consistency and quality of the tracts are improved with correction and that this correction process should be part of typical diffusion sequences acquired for tractography purposes.