Alessandro Daducci1, Jason McEwen2, Dimitri Van De Ville3,4, Jean-Philippe Thiran1, Yves Wiaux2,4
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.