A retrospective study of white matter integrity in mild cognitive impairment

摘要

Prior work has shown that white matter fiber integrity decreases in Alzheimer's disease (AD) and mild cognitive impairment (MCI). This can be achieved by quantifying anisotropic water movement in the brain using diffusion tensor imaging techniques. Since less than half (but still a considerable amount) of the MCI patients convert to AD it is important to identify features that can predict the chance of conversion to AD within a certain time frame. In this study we applied tract-based spatial statistics (TBSS) in order to perform this task, which overcomes limitations that are commonly associated with ROI-based approaches and voxel-based morphometry (VBM). Diffusion weighted images were taken from 15 healthy controls, 15 AD patients and 17 MCI patients. 8 MCI patients remained stable within 3 years of follow-up investigations ("non-converters" or MCI-nc) and 9 converted to AD ("converters" or MCI-c). Significant differences between the MCI-nc and MCI-c groups were found in large parts of the fornix, the corpus callosum and the cingulum. In comparison, the MCI-c group did not differ significantly from the AD group and the MCI-nc group exhibited features similar to the control group in most parts of the structures. These results demonstrate that, although MCI-c and MCI-nc patients were clinically similar at time of inclusion, the MCI-c group already exhibited pathologic features of fiber integrity associated with AD. This finding could lead to more powerful techniques in the early identification of AD and thus support an earlier and more successful treatment.