Introduction: High-angular resolution diffusion imaging (HARDI) is a powerful extension of MRI that maps the directional diffusion of water in the brain, based on applying diffusion-sensitized gradients in 30-100 or more different directions. In the Diffusion Tensor (DT) model, a tensor is fitted to the set of diffusion images, and maps of fiber integrity such as fractional or relative anisotro...

INTRODUCTION: Many recent techniques have been introduced for high angular resolution diffusion imaging (HARDI) [1 and references therein], to infer the diffusion or fiber orientation distribution function (ODF) of the underlying tissue structure. These methods, mostly designed for fiber tractography, are normally based on a single shell acquisition and can only recover some angular information...

In this article we develop a new method to segment Q-Ball imaging (QBI) data. We first estimate the orientation distribution function (ODF) using a fast and robust spherical harmonic (SH) method. Then, we use a region-based statistical surface evolution on this image of ODFs to efficiently find coherent white matter fiber bundles. We show that our method is appropriate to propagate through regi...

Constrained spherical deconvolution (CSD) is a new technique that, based on high-angular resolution diffusion imaging (HARDI) MR data, estimates the orientation of multiple intravoxel fiber populations within regions of complex white matter architecture, thereby overcoming the limitations of the widely used diffusion tensor imaging (DTI) technique. One of its main applications is fiber tractogr...

Obtaining information about the anatomical connectivity of the human brain, noninvasively, is a difficult challenge facing neuroscientists. The adult human brain contains tens of billions of neuronal cells, each with multiple cell contacts that form a complex web. Moreover, higher-order structures, termed neural tracts or fiber bundles, form a complicated 3D network within and connecting differ...

The claustrum and the insula are closely juxtaposed in the brain of the prosimian primate, the gray mouse lemur (Microcebus murinus). Whether the claustrum has closer affinities with the cortex or the striatum has been debated for many decades. Our observation of histological sections from primate brains and genomic data in the mouse suggest former. Given this, the present study compares the co...

BACKGROUND AND PURPOSE The purpose of this work was to test the feasibility of using high angular resolution diffusion imaging (HARDI)-based multitensor tractography to depict motor pathways in patients with brain tumors. MATERIALS AND METHODS Ten patients (6 males and 4 females) with a mean age of 52 years (range, 9-77 years) were scanned using a 1.5T clinical MR unit. Single-shot echo-plana...

A global probabilistic fiber tracking approach based on the voting process provided by the Hough transform is introduced in this work. The proposed framework tests candidate 3D curves in the volume, assigning to each one a score computed from the diffusion images, and then selects the curves with the highest scores as the potential anatomical connections. The algorithm avoids local minima by pe...

Most diffusion imaging studies have used subject registration to an atlas space for enhanced quantification of anatomy. However, standard diffusion tensor atlases lack information in regions of fiber crossing and are based on adult anatomy. The degree of error associated with applying these atlases to studies of children for example has not yet been estimated but may lead to suboptimal results....

E. Ozarslan, T. M. Shepherd, B. C. Vemuri, S. J. Blackband, T. H. Mareci National Institutes of Health, Bethesda, MD, United States, University of Florida, Gainesville, FL, United States INTRODUCTION Diffusion-weighted MRI provides a non-invasive means to map the neural connections between functionally connected regions of the central nervous system. High angular resolution diffusion imaging (H...