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bioRxiv · 10.1101/2021.03.24.436786

Anisotropy Measure from Three Diffusion-Encoding Gradient Directions

Aja-Fernandez, S.·Paris, G.·Tristan-Vega, A.
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Abstract

PurposeWe propose a method that can provide information about the anisotropy and orientation of diffusion in the brain from only 3 orthogonal gradient directions without imposing additional assumptions. MethodsThe method is based on the Diffusion Anisotropy (DiA) that measures the distance from a diffusion signal to its isotropic equivalent. The original formulation based on a Spherical Harmonics basis allows to go down to only 3 orthogonal directions in order to estimate the measure. In addition, an alternative simplification and a color-coding representation are also proposed. ResultsAcquisitions from a publicly available database are used to test the viability of the proposal. The DiA succeeded in providing anisotropy information from the white matter using only 3 diffusion-encoding directions. The price to pay for such reduced acquisition is an increment in the variability of the data and a subestimation of the metric. ConclusionsThe calculation of anisotropy information from DMRI is feasible using fewer than 6 gradient directions by using DiA. The method is totally compatible with existing acquisition protocols and it may provide complementary information about orientation in fast diffusion acquisitions.

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Aja-Fernandez, S., Paris, G., Tristan-Vega, A.. 2021-03-25. Anisotropy Measure from Three Diffusion-Encoding Gradient Directions. https://doi.org/10.1101/2021.03.24.436786

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