Diffusion tensor imaging based analysis of neurological disorders

Diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) allow in vivo investigation of molecular motion of tissue water at a microscopic level in cerebral gray matter (GM) and white matter (WM). Quantitative analysis of GM diffusivity and/or WM fiber integrity is of significant interest and promises to have a clinical impact on the investigation of many neurological diseases. This chapter briefly reviews several selected DWI/DTI studies in neurological disorders. Then, we introduce an automated framework for analysis of GM diffusivity in 76 standard anatomic subdivisions of gray matter in order to facilitate studies of neurodegenerative and other gray matter neurological diseases. The computational framework includes three enabling technologies: (1) automatic parcellation of structuralMRIGMinto 76 precisely defined neuroanatomic subregions (“76-space”), (2) automated segmentation of GM, WM and CSF based on DTI data, and (3) automatic measurement of the average apparent diffusion coefficient(ADC)in each segmentedGMsubregion.We applied this computational framework of 76-space GM diffusivity analysis on normal brains and patient brains with Creutzfeldt-Jakob disease.