Non-Gaussian diffusion imaging - A comparison of the bi-Gaussian and fourth order tenson models to diffusion tensor imaging

TL;DRAbstract

Diffusion weighted imaging (DWI) is a magnetic resonance imaging (MRI) technique that can be used to measure, in vivo, the self-diffusion of water molecules in body tissues.This reveals information about the microstructure of the underlying tissue.The simplest approach to modelling the diffusion at each voxel, known as diffusion tensor imaging (DTI), is as a Gaussian probability density function (PDF).The covariance matrix of this PDF defines a second-order tensor.Whilst this model is adequate for modelling fascicles with a single dominant orientation it is not suitable for more complex tissue architectures; e.g.crossing fascicles.This has driven the development of more sophisticated models such as high-order tensors (HOTs).The aim in fitting such models is to determine: (i) the number fascicles and their orientations and (ii) to extract scalar measures, such as fractional anisotropy (FA), to characterise the tissue microstructure.This knowledge is used for two general types of applica

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