Diffusion tensor imaging

Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that enables the measurement of the restricted diffusion of water in tissue in order to produce neural tract images instead of using this data solely for the purpose of assigning contrast or colors to pixels in a cross sectional image.

Overview

DTI is a type of diffusion MRI (dMRI) that measures the restricted diffusion of water. This method allows the mapping of the diffusion process of molecules, mainly water, in biological tissues, in vivo and non-invasively. Water molecule diffusion patterns can reveal microscopic details about tissue architecture, either normal or in a diseased state.

Principle

The principle behind DTI is based on the Brownian motion of water molecules. In an unrestricted medium, water molecules move randomly and equally in all directions, a phenomenon described as isotropic diffusion. However, in biological tissues, the diffusion of water molecules is often restricted by various barriers such as cell membranes, myelin sheaths, and protein fibers. This restriction leads to anisotropic diffusion, where water molecules move more in one direction than others.

Applications

DTI is used in the evaluation of several types of brain disorders, including stroke, multiple sclerosis, and Alzheimer's disease. It is also used in the pre-surgical planning for patients with brain tumors.

Limitations

While DTI provides valuable information about the microstructural changes occurring in various diseases, it has its limitations. These include the inability to resolve crossing fibers and the assumption of a Gaussian distribution of diffusion.

See also

• Magnetic resonance imaging
• Diffusion MRI
• Stroke
• Multiple sclerosis
• Alzheimer's disease

References

Diffusion tensor imaging Resources
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