Disruption of thalamic connectivity in Alzheimer's disease: a diffusion tensor imaging study

Area of Science:

• Neuroimaging
• Neurology
• Medical Physics

Background:

• Alzheimer's disease (AD) is a progressive neurodegenerative disorder.
• Thalamic connectivity plays a crucial role in cognitive function.
• Understanding microstructural changes in AD is vital for early diagnosis and monitoring.

Purpose of the Study:

• To evaluate the structural integrity of specific thalamic fiber tracts in different stages of Alzheimer's disease (AD) using diffusion tensor imaging (DTI).
• To identify potential DTI-based biomarkers for early AD diagnosis and disease progression monitoring.

Main Methods:

• Recruited 35 AD patients (mild, moderate, severe) and 22 normal controls (NC).
• Utilized DTI to analyze fractional anisotropy (FA), mean diffusivity (MD), and tract volume of the fornix (FX), anterior thalamic radiation (ATR), and posterior thalamic radiation (PTR).
• Employed atlas-based analysis and fiber tracking for quantitative measurements.

Main Results:

• Significant differences in FA and MD were observed in most analyzed tracts between AD patients and NC subjects.
• Progressive decline in FA and increase in MD were noted across AD severity subgroups, with the severe AD group showing widespread changes.
• Reduced tract volume in the FX and left ATR was primarily observed in the severe AD subgroup.

Conclusions:

• Thalamic connectivity integrity is progressively disrupted in Alzheimer's disease.
• DTI parameters, especially in the column and body of the fornix, show potential as early diagnostic markers for AD.
• DTI metrics can aid in monitoring disease progression in Alzheimer's disease.