Diffusion tensor imaging investigations in Alzheimer’s disease: the resurgence of white matter compromise in the cortical dysfunction of the aging brain

Abstract

Diffusion tensor imaging (DTI) is a sophisticated MRI-based neuroimaging technique that enables in vivo quantifi cation of differences in molecular diffusion at the cellular level. Owing to the highly directional architecture of white matter (WM), DTI is providing important clues of the structure and geometric organization of this neural compartment. Since DTI can detect changes even in the case of radiologically "normal" appearing WM, researchers are using the technique for the study of WM integrity at the initial stages of the most common neurodegenerative disorders. Along with a well characterized cortical pathology (neuritic plaques and intracellular neurofi brillary tangles), WM changes have been also demonstrated in Alzheimer's disease (AD). However, these changes had been for years found nonliable in the onset and progress of AD, basically due to lack of incriminatory evidence. The use of novel tools such as DTI has enabled the anatomical distribution of WM microstructural damage in the prodromal stages of AD to be gauged and determined, granting a long-delayed protagonic role to WM in the natural history of this highly prevalent neurodegenerative condition.

Structural and Functional Imaging Correlates of Cognitive and Brain Reserve Hypotheses in Healthy and Pathological Aging

“…Regarding healthy elders, we observed that CR status was only related to WM integrity in the genum of the corpus callosum. According to previous literature (Medina and Gaviria 2008 and to our earlier DTI study whereby 'age related' and 'AD-typical' topography patterns of WM loss of integrity were reported (Bosch et al 2010b), effects to this area corresponds more to typical aging and are less characteristic of early dementia.…”

The Role of Diffusion Tensor Imaging in the Study of Cognitive Aging

“…For example, in one report (Rose et al 2000), poorer MMSE score among AD patients was correlated with decreased diffusion anisotropy in the splenium of the corpus callosum. Among amnestic MCI patients and healthy age-matched controls, the same group reported that reduced FA in posterior white matter regions was associated with reduced cognitive performance, particularly in memory (Rose et al 2006;Medina and Gaviria 2008).…”

A Structural Parametrization of the Brain Using Hidden Markov Models-Based Paths in Alzheimer’s Disease

“…Finally, it might be straightforward to compare our HMM based paths to Diffusion Tensor Imaging (DTI) fibers, which has indeed proved a good tool for the diagnosis of AD [31,32]. Some could even argue that the resulting DTI tract reconstruction look similar to our computed paths (Figs.…”