INTRODUCTION Based on the idea that water diffuses preferably along the axonal trajectories, diffusion-weighted MRI can be used to map the neural connections between different regions of the human body. Although most methods developed to map anatomical connections employ data at low-b values, there has been recent interest to extend the acquisition scheme to larger diffusion weightings to incre...

Recently, carriers of a common variant in the autism risk gene, CNTNAP2, were found to have altered functional brain connectivity using functional MRI. Here, we scanned 328 young adults with high-field (4-Tesla) diffusion imaging, to test the hypothesis that carriers of this gene variant would have altered structural brain connectivity. All participants (209 women, 119 men, age: 23.4±2.17 SD ye...

Diffusion MRI (dMRI) is the unique technique to infer the microstructure of the white matter in vivo and noninvasively, by modeling the diffusion of water molecules. Ensemble Average Propagator (EAP) and Orientation Distribution Function (ODF) are two important Probability Density Functions (PDFs) which reflect the water diffusion. Estimation and processing of EAP and ODF is the central problem...

High angular resolution diffusion imaging is an increasingly important image modality. The nature of the diffusion data makes mixtures of probability distributions particularly suitable for modeling its signals. In this paper, we introduce Bayesian finite mixture models for studying the diffusion field. We apply a spatially variant mixture model to study prior distributions on the model paramet...

This paper introduces neurite orientation dispersion and density imaging (NODDI), a practical diffusion MRI technique for estimating the microstructural complexity of dendrites and axons in vivo on clinical MRI scanners. Such indices of neurites relate more directly to and provide more specific markers of brain tissue microstructure than standard indices from diffusion tensor imaging, such as f...

High Angular Resolution Diffusion Imaging (HARDI) improved many neurosurgical areas due to its ability to represent complex intra-voxel structures, but is limited for clinical use mainly due to long acquisition times, but also due to noise. To transcend these limits, our work addresses these problems by combining a state-of-the-art multi diffusion tensor model enhanced with spherical ridgelets....

Q-ball imaging (QBI) is a high angular resolution diffusion imaging (HARDI) technique which has been proven very successful in resolving multiple intravoxel fiber orientations in MR images. The standard computation of the orientation distribution function (ODF, the probability of diffusion in a given direction) from q-ball data uses linear radial projection, neglecting the change in the volume ...

In Diffusion Tensor Imaging (DTI) or High Angular Resolution Diffusion Imaging (HARDI), a tensor field or a spherical function field (e.g., an orientation distribution function field), can be estimated from measured diffusion weighted images. In this paper, inspired by the microscopic theoretical treatment of phases in liquid crystals, we introduce a novel mathematical framework, called Directo...

High angular resolution diffusion imaging (HARDI) demonstrates transient radial coherence of telencephalic white matter in the human fetus. Our objective was to define the neuroanatomic basis of this radial coherence through correlative HARDI- and postmortem tissue analyses. Applying immunomarkers to radial glial fibers (RGFs), axons, and blood vessels in 18 cases (19 gestational weeks to 3 pos...

Background and Aim: Diffusion Tensor Imaging (DTI)-based tractography can help us visualize the spatial relation of fiber tracts to brain lesions. Several factors may interfere with procedure diffusion-based tractography, especially in tumors. The current study aims discuss several solutions improve reconstruction adjacent or inside Illustrative cases are also presented. Methods Materials/Patie...