Going Beyond Diffusion Tensor Imaging: Local Reconstruction and Tractography in High Angular..

Speaker: Maxime Descoteaux, Ph.D. NMR Lab Neurospin / CEA Saclay
FRANCE Abstract:
At the current resolution of diffusion-weighted (DW) magnetic resonance imaging (MRI), research groups agree that there are between one third to two thirds of imaging voxels in the human brain white matter that contain multiple fiber bundles crossing. This presentation tackles the important problem of recovering crossing fiber bundles from high angular resolution diffusion imaging (HARDI) data. The main goal is to overcome the limitations of diffusion tensor imaging (DTI). It is well-known that imaging voxels where there are multiple fiber crossings are locations where DTI is limited and inadequate. In this presentation, a simple, fast and robust Q-ball imaging (QBI) reconstruction is presented using spherical harmonics. QBI is a recent HARDI technique that reconstructs the orientation distribution function (ODF) of the average diffusion of the water molecules in the underlying fiber population. It is able to describe multiple fiber populations crossing. From this diffusion ODF, we describe how we can reconstruct the fiber ODF in order to perform accurate tractography. We develop a new spherical deconvolution sharpening method that transforms the diffusion ODF into a fiber ODF. Finally, we develop a new deterministic tractography algorithm and a new probabilistic tractography algorithm exploiting the full multi-directional information of the fiber ODF. We show local reconstructions and tracking results on complex fiber regions with known fiber crossings from simulated HARDI data, from a biological phantom and from multiple human brain datasets. Most current DTI based methods neglect these complex fibers, which might lead to wrong interpretations of the brain anatomy and functioning.Host: Professor Richard Leahy

Location: Hedco Neurosciences Building (HNB) - 100

Audiences: Everyone Is Invited

Contact: Talyia Veal