DMRI Anatomical Constrained Tractography using proposed tissue maps

Abstract

Diffusion Magnetic Resonance Imaging (DMRI), is a technique used to map the brain's inside anatomy in vivo. The images gotten from DMRI can then be passed to reconstruction techniques that estimate the diffusion direction of the fibres at each voxel. Information that can be used to get a 3D model of the brain fibres using tractography algorithms. One inherent limitation of tractography is the determination of the accurate streamline termination point. To address this issue, researches in the field proposed the Anatomical Constrained Tractography (ACT), which is a technique that uses prior knowledge of brain anatomy to restrain the generated streamlines to be biologically coherent. To achieve this, partial volume estimations (PVE) of the different brain's tissues are needed, which are generally segmented from T1 images having a good contrast, especially between the White Matter (WM) and Grey Matter (GM) areas. The contribution of this project is to propose an alternative way to generate the needed PVE’s without using a T1 image. By using diffusion tensor (DT) measures such as Fractional Anisotropy (FA) and Mean Diffusivity (MD), we were able to extract the different brain tissue masks. Our results were promising, they gave masks that are close to the PVE maps provided with the test dataset.