title: VON MISES-FISHER MIXTURE MODEL OF THE DIFFUSION ODF.
abstract: High angular resolution diffusion imaging (HARDI) permits the computation of water molecule displacement probabilities over the sphere. This probability is often referred to as the orientation distribution function (ODF). In this paper we present a novel model for representing this diffusion ODF namely, a mixture of von Mises-Fisher (vMF) distributions. Our model is compact in that it requires very few parameters to represent complicated ODF geometries which occur specifically in the presence of heterogeneous nerve fiber orientations. We present a Riemannian geometric framework for computing intrinsic distances (in closed-form) and for performing interpolation between ODFs represented by vMF mixtures. We also present closed-form equations for entropy and variance based anisotropy measures that are then computed and illustrated for real HARDI data from a rat brain.
authors.affiliation: West Virginia University, Department of CSEE, Morgantown, WV.
authors.forename: Tim
authors.initials: T
authors.lastname: McGraw
authors.forename: Baba C
authors.initials: BC
authors.lastname: Vemuri
authors.forename: Bob
authors.initials: B
authors.lastname: Yezierski
authors.forename: Thomas
authors.initials: T
authors.lastname: Mareci