Diffusion MRI tractography can be used to evaluate for brain pathology by measuring for pathlength, for example. The pathlength constitutes neuronal brain connectivity between two specified brain locations. An abnormal pathlength could be increased or decreased. A significant change in pathlength should point to a specific brain pathology depending on the location of the path. A recent study on Traumatic Brain Injury shows a significant decrease in path length between the genu of the corpus callosum and the frontal lobe. This white matter structure is often related to diffuse axonal injury (Pannek K, etal. The average pathlength map: A diffusion MRI Tractography-derived index for study of brain pathology. NeuroImage. 55 (2011) 133-141).
Diffusion MRI Tractography is related to structural brain changes. It would be interesting to evaluate for functional brain changes and its relation to functional connectivity. Also, it would be interesting to evaluate for structural connectivity in the so-called functional brain disorders, and find out if they also have a structural component.
Adolfo Cotter, MD