Diffusion Simulation Tractography for High Angular Resolution Diffusion Imaging

Introduction While the standard diffusion tensor imaging (DTI) approach has proven to be a valuable tool in detecting local tissue structure and reconstructing neural fiber networks in brain, it cannot accurately reveal the white matter structure in the presence of multiple fiber orientations within a single voxel. In particular, for crossed fibers, the second-order diffusion tensor model fails to describe such a mixture of fiber orientations and the principal axis of the tensor in general will not lie along any of those directions. Recently, high angular resolution diffusion imaging (HARDI) methods [1,2] have been proposed to capture and estimate the multiple fiber populations in complex tissues, where the diffusion imaging is used with diffusion-weighting applied along many gradient directions with high sensitivity (large bvalues). Here, based on the HARDI technique, we present a novel tractography approach to map white matter connections in regions with entangled fiber tracts.