title: Multiple Q-shell ODF reconstruction in Q-ball imaging.
abstract: Q-ball imaging (QBI) is a high angular resolution diffusion imaging (HARDI) technique which has been proven very successful in resolving multiple intravoxel fiber orientations in MR images. The standard computation of the orientation distribution function (ODF, the probability of diffusion in a given direction) from q-ball uses linear radial projection, neglecting the change in the volume element along the ray, thereby resulting in distributions different from the true ODFs. A new technique has been recently proposed that, by considering the solid angle factor, uses the mathematically correct definition of the ODF and results in a dimensionless and normalized ODF expression from a single q-shell. In this paper, we extend this technique in order to exploit HARDI data from multiple q-shells. We consider the more flexible multi-exponential model for the diffusion signal, and show how to efficiently compute the ODFs in constant solid angle. We describe our method and demonstrate its improved performance on both artificial and real HARDI data.
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, USA. iman@umn.edu
authors.forename: Iman
authors.initials: I
authors.lastname: Aganj
authors.forename: Christophe
authors.initials: C
authors.lastname: Lenglet
authors.forename: Guillermo
authors.initials: G
authors.lastname: Sapiro
authors.forename: Essa
authors.initials: E
authors.lastname: Yacoub
authors.forename: Kamil
authors.initials: K
authors.lastname: Ugurbil
authors.forename: Noam
authors.initials: N
authors.lastname: Harel
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity