QBI in 162 directions (b=4500 s/mm2). In panel a), colors encode principal sheet direction and both techniques show good qualitative agreement. However, closer inspection of the SNDFs shows intravoxel sheet crossing which cannot be resolved with conventional DTI. Panel b) illustrates this for the framed voxel from a), where the DTI sheet normal direction lies in between two distinct sheet popul...

Many recent single-shell high angular resolution diffusion imaging reconstruction techniques have been introduced to reconstruct orientation distribution functions (ODF) that only capture angular information contained in the diffusion process of water molecules. By also considering the radial part of the diffusion signal, the reconstruction of the ensemble average diffusion propagator (EAP) of ...

Diffusion tensor imaging (DTI) accurately delineates white matter pathways when the Gaussian model of diffusion is valid. However, DTI yields erroneous results when diffusion takes on a more complex distribution, as is the case in the brain when fiber tracts cross. High angular resolution diffusion imaging (HARDI) overcomes this limitation of DTI by more fully characterizing the angular depende...

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...

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...

BACKGROUND In Diffusion Tensor Imaging (DTI), Riemannian framework based on Information Geometry theory has been proposed for processing tensors on estimation, interpolation, smoothing, regularization, segmentation, statistical test and so on. Recently Riemannian framework has been generalized to Orientation Distribution Function (ODF) and it is applicable to any Probability Density Function (P...

The elastic properties of several monocrystalline and textured Nickel-base alloys were determined as a function of orientation in single crystals and of direction in textured materials by a dynamic resonance technique between 20°C and 1200°C. For the quantitative description of the elastic behavior of anisotropic solids the elastic single crystal constants, the texture, and the orientation are ...

Author(s) of this paper may load this reprint on their own web site provided that this cover page is retained. Republication of this article or its storage in electronic databases or the like is not permitted without prior permission in writing from the IUCr. The wide availability of X-ray area detectors provides an opportunity for using synchrotron radiation based X-ray diffraction for the det...

erry A. Gaige yuk Sang Kwon uangping Dai ictor C. Cabral uopeng Wang oon Sung Nam evin P. Engelward an J Wedeen eter T. C. So ichard J. Gilbert assachusetts Institute of Technology epartment of Mechanical and Biological Engineering ambridge, Massachusetts 02139 and assachusetts General Hospital thinoula A. Martinos Center for Biomedical Imaging harlestown, Massachusetts 02129 Abstract. The tong...

Diffusion tensor imaging (DTI) MRI is a noninvasive imaging method of the cerebral tissues whose fibers directions are not evaluated correctly in the regions of the crossing fibers. For the same reason the high angular resolution diffusion images (HARDI) are used for estimation of the fiber direction in each voxel. One of the main methods to specify the direction of fibers is usage of the spher...