KSEF RDE: Generalized Diffusion Simulation-Based Tractography for Mapping Human Brain

Abstract The overall goal of this project is to develop innovative mathematical models, sophisticated numerical techniques, and tailored experiments, to demonstrate the feasibility of combining diffusion simulation-based fiber tractography (DST) with generalized diffusion tensor (GDT) model on high angular diffusion weighted imaging (HARDI) datasets, to noinvasively in vivo reconstruct major and secondary white matter fiber tracts (WMFTs) of human brain. This study will develop new neuroinformatics concepts and analysis tools to advance white matter fiber tractography based on the diffusion weighted imaging (DWI) modality, and to guide the directions of developing next generation high fidelity human brain white matter tractography. Standard diffusion tensor magnetic resonance imaging (DT -MRI) based on the 2nd order tensor model has limitations in its ability to distinguish complex fiber tracts. Current version of DST is unable to reconstruct small complex WMFTs that are important for mapping human brain connectivity. We propose to use GDT to better model the diffusion process in human brain and to use DST to more accurately simulate the underlying physical diffusion process of human brain. The combination of these two superior technologies forms the framework of generalized diffusion simulation-based tractography (GDST). The hypothesis of this work is that robust fiber tracking algorithms such as DST can extract more information from the DWI data with high angular resolution. Thus, GDST advances fiber tractography in both fronts simultaneously - more sensitive tracking algorithm applied to higher resolution data, compared to standard streamlinebased tracking algorithm applied to standard DT -MRI data. The specific aims of this project are in (1) the development of mathematical models to incorporate DST with GDT, and (2) the development of numerical techniques and software tools to implement GDST. The success ofthis project will have high impact on the human brain mapping research, as well as on the possible clinical studies related to certain brain white matter disorders. Keywords: Neuroimaging, Diffusion tensor imaging, Human brain, White matter, Tractography §