Differential Tractography as an Imaging Biomarker for Neurodegeneration
Diffusion MRI tractography uses the diffusion of water molecules to generate contrast in MR images, and is useful for showing brain architecture in human subjects. The structure of a patient’s brain can yield key insights that are helpful in diagnosing diseases that manifest as brain atrophy, such as multiple sclerosis and Huntington disease. However, the ability of these techniques to specify neuropathological change is limited, and a reliable and sensitive method to reveal the exact segment of fiber pathways affected by neurodegeneration is yet to be developed. A more sensitive and accurate method of imaging neurodegeneration will allow for quicker diagnosis and an earlier start to treatment for individuals with these devastating diseases.
Description
Researchers have imbued diffusion MRI tractography with four novel approaches that allow it to identify the exact segment of pathways with neurodegeneration, enabling a quantitative and objective approach to investigating neurodegeneration. A fundamental switch from the traditional use of the absolute value of anisotrophic diffusion to the difference of anisotrophic diffusion creates a novel concept of tractography termed “differential tractography.” Instead of showing only the existence of fiber bundles in the brain, differential tractography tracks the exact segments of pathways that exhibit a substantial change in anisotrophic diffusion, providing highly specific findings related to disease development while ignoring unaffected pathways. This method allows for an estimated positive predictive value of 97%, demonstrating its reliability and accuracy.Applications
· Reveal location and quantify severity of neurodegeneration· Diagnostic and prognostic evaluation
· Assessing patient’s response to treatment
Advantages
· Increased ability to track change in neurodegeneration· Ability to track only affected fiber segments, while ignoring unaffected pathways
· Can be used for early-stage, progressive, and established late-stage neurodegeneration
· Reliable and accurate