DIFFUSION TENSOR IMAGING [ back to Neuroimaging ]
Diffusion Tensor Imaging is a form of MRI using magnetic pulses that measures the diffusion (outward movement) of water molecules in relation to brain fibers in 6 different spatial planes. The basic premise is that if the white matter axon tracts are intact, water molecules will move parallel to them when displaced by the energy of the magnetic field; but if the brain fibers are damaged by trauma, some of the water molecules will pass through them in a perpendicular direction. DTI is an advance over the earlier imaging method known as DWI (diffusion weighted imaging) which measured movement of water molecules in just 3 planes. Increased diffusivity of brain tissue following trauma is consistent with microscopic damage.