This paper describes an automated model selection method for analysing the relationship between the order of the spherical harmonic basis functions used to fit high angular resolution diffusion imaging (HARDI) data and the accuracy of the fitting results. The method performs statistical inference on the spherical harmonic expansion coefficients and uses a backward elimination procedure to remov...

Graph theory can be applied to matrices that represent the brain’s anatomical connections, to better understand global properties of anatomical networks, such as their clustering, efficiency and “small-world” topology. Network analysis is popular in adult studies of connectivity, but only one study – in just 30 subjects – has examined how network measures change as the brain develops. Here we a...

Introduction: With acquisition protocols such as high angular resolution diffusion imaging, head motion can become an issue. Although the misalignment between diffusion-weighted images (DWIs) can be corrected in a post-processing step [1,2], this might increase partial volume effects, because of the relatively low spatial resolution of DWIs and interpolation in the registration procedure. If ab...

Diffusion-MRI provides a unique window on brain anatomy and insights into aspects of brain structure in living humans that could not be studied previously. There is a major effort in this rapidly evolving field of research to develop algorithms that provide detailed information on the white matter fibre architecture and disorders in the brain. High angular resolution diffusion imaging (HARDI) p...

In recent years, the use of brain diffusion MRI has led to the hypothesis that children with autism spectrum disorder (ASD) show abnormally connected brains. We used the model of disease-discordant identical twins to test the hypothesis that higher-order diffusion MRI protocols are able to detect abnormal connectivity in a single subject. We studied the structural connectivity of the brain of a...

It's well known that in diffusion MRI (dMRI), fibre crossing is an important problem for most existing diffusion tensor imaging (DTI) based tractography algorithms. To overcome these limitations, High Angular Resolution Diffusion Imaging (HARDI) based tractography has been proposed with a particular emphasis on the the Orientation Distribution Function (ODF). In this paper, we advocate the use ...

Fractional anisotropy (FA), a very widely used measure of fiber integrity based on diffusion tensor imaging (DTI), is a problematic concept as it is influenced by several quantities including the number of dominant fiber directions within each voxel, each fiber's anisotropy, and partial volume effects from neighboring gray matter. With High-angular resolution diffusion imaging (HARDI) and the t...

In this paper, a new single image acquisition super-resolution method is proposed to increase image resolution of diffusion weighted (DW) images. Based on a nonlocal patch-based strategy, the proposed method uses a non-diffusion image (b0) to constrain the reconstruction of DW images. An extensive validation is presented with a gold standard built on averaging 10 high-resolution DW acquisitions...

In this paper, we present a novel variational formulation for restor­ ing high angular resolution diffusion imaging (HARDI) data. The restoration formulation involves smoothing signal measurements over the spherical do­ main and across the 3D image lattice. The regularization across the lattice is achieved using a total variation (TV) norm based scheme, while the finite ele­ ment method (FEM) w...