We review the normal anatomy of the white matter (WM) tracts as they appear on directional diffusion tensor imaging (DTI) color maps and tractography. Anatomic gross dissection photographs are correlated with tractography to review the anatomy of those tracts, which are readily seen in most cases. We describe the principles of diffusion contrast and anisotropy, as well as their main clinical applications in developmental abnormalities, demyelinating disease, ischemic disease, infectious diseases, neurodegenerative disordes, neoplasms andpreoperative studies. DTI MR images were obtained with a 3T system...

Diffusion magnetic resonance (MR) imaging is evolving into a potent tool in the examination of the central nervous system. Although it is often used for the detection of acute ischemia, evaluation of directionality in a diffusion measurement can be useful in white matter, which demonstrates strong diffusion anisotropy. Techniques such as diffusion-tensor imaging offer a glimpse into brain microstructure at a scale that is not easily accessible with other modalities, in some cases improving the detection and characterization of white matter abnormalities. Diffusion MR tractography...

Diffusion contrast is based on the self-diffusion of water molecules in tissue. Although a variety of sequences are now used to acquire DW images, all DW sequences include two equal and opposing motion-probing gradients. Diffusion is anisotropic (directionally dependent) in WM fiber tracts, as axonal membranes and myelin sheaths represent barriers to the motion of water molecules in directions not parallel to their own orientation. The direction of maximum diffusivity has been shown to coincide with the WM fiber tract orientation . This information is...

• Diffusion tensor imaging and tractography are a key tool in the anatomical study of white matter fibers and projection, association and commissural fibers that improves conventional magnetic resonance imaging. • Diffusion tensor imaging is able to show abnormalities in a wide variety of diseases such as developmental disorders or psychiatric disorders and is specially useful in the assessment of ischemic disease, multiple sclerosis and tumors. • The use of tensor imaging in conjunction with functional studies (motor, visual, speech or memory), cortical mapping and...

Dr. Manuel Recio Rodríguez. Hospital Quirón Madrid. [email protected]

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