Abstract #3929

Harmonic Analysis of Spherical Sampling in Diffusion MRI

Alessandro Daducci¹, Jason McEwen², Dimitri Van De Ville^3,4, Jean-Philippe Thiran¹, Yves Wiaux^2,4

¹Signal Processing Laboratory (LTS5), cole Polytechnique Fdrale de Lausanne (EPFL), Lausanne, Switzerland; ²Institute of Electrical Engineering, cole Polytechnique Fdrale de Lausanne (EPFL), Lausanne, Switzerland; ³Institute of Bioengineering, cole Polytechnique Fdrale de Lausanne (EPFL), Lausanne, Switzerland; ⁴Department of Radiology & Medical Informatics, University of Geneva (UniGE), Geneva, Switzerland

Diffusion MRI has become a powerful tool to non-invasively study white-matter integrity in the brain. Recently multi-shell spherical acquisitions have been advocated for mapping the diffusion signal, notably through its ODF, with a lower number of q-space samples, hence providing acceleration. In this context the spherical harmonic (SH) transform has gained a great deal of popularity. This study presents a theoretical framework and numerical simulations aiming to provide initial guidance in designing efficient multi-shell spherical sampling strategies in a model independent approach. It is based on the use of equiangular grids on the sphere, for which exact sampling theorems exist.