An optimal direction strategy of diffusion sensitive gradient mangnetic fields in magnetic resonance diffusion tensor imaging based on generalized Fibonacci sequence

Abstract

In order to accurately investigate the directionally anisotropic diffusion information of water molecule in tissue, the diffusion sensitive gradient fields need to be applied alone many directions in order to obtain corresponding diffusion coefficients in diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI) experiments. The problems facing to current diffusion sensitive gradient magnetic fields encoding schemes include the spatial uniformity of directions needs to be improved, there is no general direction design for arbitrary number of directions, flaw in any directions will cause failure or defect of the whole dataset. In this paper, we provide a generalized Fibonacci number based direction encoding scheme. This scheme can generate nearly uniform distribution for arbitrary number of directions and satisfy the spatial uniformity using partial directions from one raw data set. Besides, the diffusion sensitive gradients of neighboring directions are nearly opposite, which will reduce eddy current induced by rapid varying gradient magnetic fields.