Diffusion Tensor Imaging

Synonyms

DTI

Definition

Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that reveals the integrity of white matter tracts that link regions of the brain to each other.

DTI exploits the characteristic that water molecules are in constant motion. In regions such as the ventricles, which offer little physical constraint, movement occurs randomly in every direction. In contrast, water molecules in white matter fibers are constrained by the physical boundaries of the axon sheath, which cause greater movement along the long axis of the fiber than across it.

The diffusion properties of water molecules are studied within and between three-dimensional elements called voxels. The technique is called diffusion tensor imaging because a tensor, a mathematical description of the orientation and magnitude of diffusion, is computed for each voxel. Images acquired in different planes will highlight different white matter tracts or provide different views of them. Within a...