Improving the Fit of the Diffusion Kurtosis Tensor by Emphasizing the Directions of Re- Stricted Water Motion

Introduction In conventional diffusion tensor imaging (DTI), a Gaussian propagator function of the diffusing spins is postulated. In biological tissue however, substantial deviations from this Gaussian diffusion are observed [1], containing additional information on the tissue microstructure. For the quantification of these deviations, the kurtosis of the propagator function has been proposed [2]. The directional dependence of the kurtosis can be modelled using the diffusion kurtosis tensor (DKT) [3]. Usually, the DKT is calculated from the kurtosis values measured in different directions using a pseudoinverse matrix. The aim of this work was to evaluate the currently proposed kurtosis tensor model, especially considering the fit quality of the DKT and to improve the calculation if needed. This is investigated under well-defined conditions using recently developed diffusion phantoms.