1Psychology, Carnegie Mellon University, Pittsburgh, PA, United States
The brain tissue is known to be bi-exponential in diffusion weighting at a high b value. The diffusion spectrum imaging (DSI) employs a wide range of b values with a peak value greater than 5000 and hence the diffusion in DSI should be considered to be bi-exponential. However, the conventional analysis of DSI has not considered the bi-exponential diffusion weighting. The bi-exponential diffusion weighting in DSI has been accounted for by replacing the acquired b with an adjusted b* which can be obtained by a simple nonlinear curve fitting. The bi-exponentially adjusted b* was experimentally confirmed to be effective in improving the fiber tracts particularly through the multiple fiber crossing regions.