Following the Spreading of Brain Structural Changes in Alzheimer's Disease: A Longitudinal, Multimodal MRI Study
Marina Weiler1,2, Federica Agosta1, Elisa Canu1
1Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
Background:
Longitudinal MRI studies in Alzheimer's disease (AD) are one of the most reliable way to track brain changes along the course of the disease.
Objective:
To investigate the evolution of grey matter (GM) atrophy and white matter (WM) damage in AD patients, and to assess the relationships of MRI changes with baseline clinical and cognitive variables and their evolution over time.
Methods:
Clinical, neuropsychological, and MRI assessments (T1-weighted and diffusion tensor [DT]-MRI) were obtained from 14 patients with AD at baseline and after a 16 ± 3 month period. Lumbar puncture was obtained at study entry. At baseline, AD patients were compared to 37 controls. GM atrophy progression was assessed with tensor-based morphometry and GM volumes of interest, and WM damage progression using tract-based spatial statistics and tractography.
Results:
At baseline, patients showed cortical atrophy in the medial temporal and parietal regions and a widespread pattern of WM damage involving the corpus callosum, cingulum, and temporo-occipital, parietal, and frontal WM tracts. During follow up, AD patients showed total GM atrophy, while total WM volume did not change. GM tissue loss was found in frontal, temporal, and parietal regions. In addition, AD patients showed a progression of WM microstructural damage to the corpus callosum, cingulum, fronto-parietal and temporo-occipital connections bilaterally. Patients with higher baseline cerebrospinal fluid total tau showed greater WM integrity loss at follow up. GM and WM changes over time did not correlate with each other nor with cognitive evolution.
Conclusion:
In AD, GM atrophy and WM tract damage are likely to progress, at least partially, independently. This study suggests that a multimodal imaging approach, which includes both T1-weighted and DT MR imaging, may provide additional markers to monitor disease progression.
Insights
Alzheimer's disease patients experience progressive grey matter atrophy and white matter damage, which appear to occur independently. Multimodal MRI may offer valuable markers for tracking disease progression.
Area of Science:
- Neuroimaging
- Neurology
- Medical Research
Background:
- Longitudinal MRI studies are crucial for tracking brain changes in Alzheimer's disease (AD).
- Understanding the progression of grey matter (GM) atrophy and white matter (WM) damage is vital for AD management.
Purpose of the Study:
- To investigate the evolution of GM atrophy and WM damage in AD patients.
- To assess the relationship between MRI changes and clinical/cognitive variables over time.
Main Methods:
- 14 AD patients and 37 controls underwent clinical, neuropsychological, and MRI (T1-weighted, DT-MRI) assessments at baseline and follow-up.
- GM atrophy progression was analyzed using tensor-based morphometry and GM volumes of interest.
- WM damage progression was evaluated using tract-based spatial statistics and tractography.
Main Results:
- AD patients exhibited baseline cortical atrophy and widespread WM damage.
- Over time, AD patients showed significant GM atrophy, particularly in frontal, temporal, and parietal regions.
- WM microstructural damage progressed, especially in the corpus callosum, cingulum, and fronto-parietal/temporo-occipital connections. Higher baseline tau levels correlated with greater WM integrity loss.
Conclusions:
- GM atrophy and WM tract damage in AD likely progress independently.
- Multimodal imaging, combining T1-weighted and DT-MRI, may provide enhanced markers for monitoring AD progression.
