title: Estimation of the CSA-ODF using Bayesian compressed sensing of multi-shell HARDI.
abstract: OBJECTIVE
  Diffusion MRI provides important information about the brain white matter structures and has opened new avenues for neuroscience and translational research. However, acquisition time needed for advanced applications can still be a challenge in clinical settings. There is consequently a need to accelerate diffusion MRI acquisitions.
  
  
  METHODS
  A multi-task Bayesian compressive sensing (MT-BCS) framework is proposed to directly estimate the constant solid angle orientation distribution function (CSA-ODF) from under-sampled (i.e., accelerated image acquisition) multi-shell high angular resolution diffusion imaging (HARDI) datasets, and accurately recover HARDI data at higher resolution in q-space. The proposed MT-BCS approach exploits the spatial redundancy of the data by modeling the statistical relationships within groups (clusters) of diffusion signal. This framework also provides uncertainty estimates of the computed CSA-ODF and diffusion signal, directly computed from the compressive measurements. Experiments validating the proposed framework are performed using realistic multi-shell synthetic images and in vivo multi-shell high angular resolution HARDI datasets.
  
  
  RESULTS
  Results indicate a practical reduction in the number of required diffusion volumes (q-space samples) by at least a factor of four to estimate the CSA-ODF from multi-shell data.
  
  
  CONCLUSIONS
  This work presents, for the first time, a multi-task Bayesian compressive sensing approach to simultaneously estimate the full posterior of the CSA-ODF and diffusion-weighted volumes from multi-shell HARDI acquisitions. It demonstrates improvement of the quality of acquired datasets by means of CS de-noising, and accurate estimation of the CSA-ODF, as well as enables a reduction in the acquisition time by a factor of two to four, especially when "staggered" q-space sampling schemes are used. The proposed MT-BCS framework can naturally be combined with parallel MR imaging to further accelerate HARDI acquisitions.
authors: Radiology - CMRR, University of Minnesota, Minneapolis, Minnesota, USA.
authors: Julio M
authors: JM
authors: Duarte-Carvajalino
authors: Christophe
authors: C
authors: Lenglet
authors: Junqian
authors: J
authors: Xu
authors: Essa
authors: E
authors: Yacoub
authors: Kamil
authors: K
authors: Ugurbil
authors: Steen
authors: S
authors: Moeller
authors: Lawrence
authors: L
authors: Carin
authors: Guillermo
authors: G
authors: Sapiro
mesh_terms: D001499:Bayes Theorem; D044962:Data Compression; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D066127:White Matter
keywords: Bayesian compressed sensing (BCS); Dirichlet process; constant solid angle (CSA); high angular resolution diffusion imaging (HARDI); multi-task; orientation distribution function (ODF)