Importance of Multiscale Analysis in HARDI Studies

Irina Kezele¹, Cyril Poupon¹, Maxime Descoteaux¹, Fabrice Poupon¹, Jean-Franois Mangin¹

High angular resolution distribution diffusion imaging (HARDI) implicitly captures information about the structure in which the diffusion process takes place. HARDI allows examination of relatively wide range of diffusion signal angular frequencies that, due to the complexity of both diffusion process and its milieu, may spread over multiple bands. In consequence, we opt for multiscale analysis, probing all frequencies, but also favouring those frequencies that are more in concordance with our specific aims, which are to deduce and sharpen fibre distributions. Inherent HARDI signal sphericity motivated us to take on the concepts of multiscale spherical wavelet analysis. We show the importance of multiscale signal analysis, and how different angular frequency bands may capture complementary information on underlying fibre distribution.