What is diffusion tensor imaging used for?
Diffusion tensor imaging (DTI) is a promising method for characterizing microstructural changes or differences with neuropathology and treatment. The diffusion tensor may be used to characterize the magnitude, the degree of anisotropy, and the orientation of directional diffusion.
Is diffusion tensor imaging invasive?
Using MRI technology, DTI tractography is non-invasive and uses radio waves and a magnetic field to produce images of the brain, tissues and skull.
How does diffusion tensor imaging work?
In simplified terms, diffusion imaging works by introducing extra gradient pulses whose effect “cancels out” for stationary water molecules, and causes a random phase shift for molecules that diffuse. Due to their random phase, signal from diffusing molecules is lost.
Is diffusion tensor imaging expensive?
Results: The total direct costs of DTI and MR tractography for a 1.5-T system with 15 encoding directions were US $97. Variable cost was $76.80 and fixed cost was $20.20.
How is DTI performed?
The analysis of water diffusion is performed by applying magnetic field gradients to generate an image that is sensitized to diffusion in a particular direction. In other words, the DTI technique involves the delivery of external magnetic pulses to impose a random phase shift for water molecules that diffuse.
What does a DTI show?
Diffusion Tensor Imaging (DTI) is a relatively new imaging technique that can be used to evaluate white matter in the brain. Using DTI, the orientation and direction of white matter fiber tracts can be visualized and quantified (see Figure below which shows visualization of white matter fiber bundles in the brain).
How is Tractography done?
Tractography is performed using data from diffusion MRI. Bundles of axons provide a barrier to perpendicular diffusion and a path for parallel diffusion along the orientation of the fibers. Anisotropic diffusion is expected to be increased in areas of high mature axonal order.
Why Is DTI useful?
DTI measures diffusion properties and consequently allows spatial description of the medium under study. The technique is particularly useful in the study of white matter tracts in the brain since the mobility of water is restricted perpendicular to the axons oriented along the fiber tracts (anisotropic diffusion).
What is the purpose of tractography?
Magnetic resonance diffusion tractography is a method for identifying white matter pathways in the living human brain. These pathways form the substrate for information transfer between remote brain regions and are therefore central to our understanding of function in both the normal and diseased brain.
How does diffusion tractography work?
Diffusion tractography uses non-invasive brain imaging data to trace fibre bundles in the human brain in vivo. This raises immediate possibilities for clinical application but responsible use of this approach requires careful consideration of the scope and limitations of the technique.
What is diffusion tractography?
What is white matter tractography?
WHITE MATTER TRACTOGRAPHY (WMT) White Matter Tractography techniques estimate the connectivity patterns between different brain regions from the continuity in the local estimates of fiber direction at each voxel. To date, a large number of WMT algorithms have been proposed.