Brain structural changes in the course of Alzheimer’s disease (P6.214)

Objective. To investigate gray (GM) and white matter (WM) structural changes in Alzheimer’s disease (AD) patients and the relationship between CSF measures at baseline and their brain structural progressive changes over time. Background. Although AD is long known to affect both GM and WM, very few longitudinal studies investigated the AD progression of brain WM structural alterations. Methods. T1-weighted and diffusion tensor (DT) MRI from 14 patients with probable AD were obtained at baseline and after a mean follow-up of 16 months. At baseline, CSF samples from patients and MRI from 37 controls were also acquired. Regional GM volume loss and DT MRI metrics from the interhemispheric and major long-association WM tracts were obtained. MRI metrics were compared between patients and controls, and changes over time were evaluated in patients. Results. Compared to controls, patients showed GM atrophy in the medial temporal and inferior parietal regions, as well as WM damage of the corpus callosum (CC), bilateral cingulum, inferior (ILF) and superior longitudinal fasciculus (SLF), left corticospinal tract and uncinate fasciculus. At follow-up, additional damage was observed in CC, bilateral SLF, right cingulum, and left ILF. No further GM damage was detected. Patients with higher CSF total-tau levels presented greater WM damage over time in the right cingulum. Conclusions. Although AD patients already presented GM volume loss and reduced WM integrity at baseline, considerable WM changes over time were detected. Interestingly, only WM changes over time in regions typically hit by the disease were related to the baseline high levels of CSF total-tau, suggesting that DT MRI offers potential markers of neurodegeneration in AD. Funding. Italian Ministry of Health (#GR-2010-2303035).