Diffusion Tensor Imaging (DTI)

Diffusion tensor imaging (DTI) is a MR-based neuroimaging technique that allows us to visualize the location, the orientation, and the anisotropy of the brain's white matter tracts.

Technique

The architecture of the axons in parallel bundles and their myelin shield facilitates the diffusion of the water molecules along their main direction. If we apply diffusion gradients in at least 6 non-collinear directions, it is possible to calculate, for each pixel, a tensor (i.e. a 3*3 matrix) that describes this diffusion anisotropy. The fiber direction is indicated by the tensor’s main eigenvector. This vector can be color-coded, yielding a cartography of the tracts’ position, direction (red for RL, blue for FH, and green for AP), and anisotropy. In addition, the regional apparent diffusion coefficient (ADC) and fractional anisotropy (FA) can be quantified.

Clinical applications

• Tract-specific localization of white matter lesions
• Localization of tumors in relation to the white matter tracts (infiltration, deflection)
• Localization of the main white matter tracts for neurosurgical planning
• Assessment of the white matter maturation

Synonyms: Diffusion Tensor Imaging, DTI, Fiber Tracking, Tractography