Diffusion MR Imaging of White Matter Pathways: Visualization and Quantitative Evaluation

Diffusion tensor imaging (DTI) is one of the most promising MRI techniques for characterizing microstructural changes of cerebral white matter in brain research and clinical applications. The number of DTI studies is increasing, and more than 7500 articles have been published over the last decade. DTI enables visualization and characterization of white matter tracts in vivo by providing a unique image contrast on white matter that is unavailable with routine MR techniques; this allows three-dimensional (3D) visualization of neuronal pathways and quantification of the diffusion properties of white matter. Since its introduction in 1994, DTI has been used to study the structure of white matter and changes to its integrity within normal brains and brains affected by aging, stroke, dementia, psychiatric disorder, tumor, and other conditions. In this paper, the technical aspects and clinical applications of DTI are reviewed with a focus on clinical use and in vivo studies. The strengths and weaknesses of the approach are discussed and current extensions of the technology (q-space imaging and diffusional kurtosis imaging) are summarized.