Prediction of dementia using diffusion tensor MRI measures: the OPTIMAL collaboration

Area of Science:

• Neuroimaging
• White Matter Integrity
• Vascular Cognitive Impairment

Background:

• Diffusion tensor imaging (DTI) measures white matter (WM) integrity.
• WM damage is implicated in cognitive decline and dementia risk, particularly in small vessel disease (SVD).
• Predictive markers for dementia in SVD are crucial for clinical trials.

Purpose of the Study:

• To investigate the association between DTI measures and cognition cross-sectionally.
• To determine if DTI measures predict future dementia risk across varying SVD severity.
• To assess the added predictive value of DTI and other MRI markers for dementia in SVD.

Main Methods:

• Analysis of six international cohorts with prospective dementia incidence data from three cohorts.
• Testing associations between six DTI measures and cognition/dementia conversion.
• Evaluating the incremental predictive contribution of DTI and conventional MRI markers for SVD.

Main Results:

• Mean diffusivity (MD) median showed significant correlation with cognition across all cohorts.
• Baseline MD median predicted dementia conversion, with change in MD median also predictive in severe SVD.
• Multimodal MRI models incorporating DTI and other MRI markers yielded the best predictive performance.

Conclusions:

• WM alterations play a key role in dementia pathogenesis in SVD.
• DTI measures, such as MD median, are valuable clinical risk predictors for dementia.
• The utility of other MRI markers in prediction varies with SVD severity.