PURPOSE To correct distortions caused by eddy currents induced by large diffusion gradients during high angular resolution diffusion imaging without any auxiliary reference scans. MATERIALS AND METHODS Image distortion parameters were obtained by image coregistration, performed only between diffusion-weighted images with close diffusion gradient orientations. A linear model that describes dis...

INTRODUCTION: Diffusion MRI is a unique noninvasive imaging technique capable of quantifying and visualizing the angular distribution and the anisotropy of the white matter fibers. Several approaches such as diffusion tensor imaging, q-ball imaging (QBI), spherical deconvolution and many others high angular resolution diffusion imaging (HARDI) have been proposed to describe the angular distribu...

One goal of in vivo neuroimaging is the detection of neurodegenerative processes and anatomical reorganizations after spinal cord (SC) injury. Non-invasive examination of white matter fibers in the living SC can be conducted using magnetic resonance diffusion-weighted imaging. However, this technique is challenging at the spinal level due to the small cross-sectional size of the cord and the pr...

33 34 Resting state functional connectivity MRI (fcMRI) is widely used to investigate 35 brain networks that exhibit correlated fluctuations. While fcMRI does not provide direct 36 measurement of anatomic connectivity, accumulating evidence suggests it is sufficiently 37 constrained by anatomy to allow the architecture of distinct brain systems to be 38 characterized. fcMRI is particularly usef...

Resting state functional connectivity MRI (fcMRI) is widely used to investigate brain networks that exhibit correlated fluctuations. While fcMRI does not provide direct measurement of anatomic connectivity, accumulating evidence suggests it is sufficiently constrained by anatomy to allow the architecture of distinct brain systems to be characterized. fcMRI is particularly useful for characteriz...

We propose a method to create a dual tensor atlas from multiple coregistered non-HARDI datasets. Increased angular resolution is ensured by random variations of subject positioning in the scanner and different local rotations applied during coregistration resulting in dispersed gradient directions. Simulations incorporating residual coregistration misalignments show that using 10 subjects shoul...

White matter fiber clustering aims to get insight about anatomical structures in order to generate atlases, perform clear visualizations, and compute statistics across subjects, all important and current neuroimaging problems. In this work, we present a diffusion maps clustering method applied to diffusion MRI in order to segment complex white matter fiber bundles. It is well known that diffusi...

Introduction: The Orientation Distribution Function (ODF), the angular profile of the diffusion probability density function of water molecules, can be estimated from High Angular Resolution Diffusion Imaging (HARDI) data [2]. We present an extension of voxel-based morphometry to ODFs and apply it to brain asymmetry. While little is known about white matter connectivity asymmetry, several recen...

High angular resolution diffusion imaging (HARDI) has opened up new perspectives for the delineation of crossing and branching fiber pathways by orientation distribution function (ODF). The fiber orientations contained in an imaging voxel are the key factor in tractography. To extract real fiber orientations from ODF, a hybrid method is proposed for computing the principal directions of ODF by ...