EVALUATING SAMPLE-SIZE EFFICIENCY AND SENSITIVITY OF TRACTOMETRY IN ALZHEIMER'S DISEASE
Yixue Feng1, Julio E Villalón-Reina1, Iyad Ba Gari1
1Imaging Genetics Center, Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Marina del Rey, CA, United States.
Biorxiv : the Preprint Server for Biology
|November 26, 2025
Summary
Tractometry analysis reveals that while coarser segments detect widespread dementia effects with fewer subjects, finer segments pinpoint subtle amyloid effects requiring larger cohorts. Study design impacts sensitivity and specificity for white matter analysis.
Area of Science:
- Neuroimaging
- White Matter Microstructure Analysis
- Computational Neuroscience
Background:
- Tractometry enables quantitative analysis of white matter.
- Impact of study design on tractometry sensitivity/specificity is unclear.
- Dementia and amyloid effects on white matter are of significant interest.
Purpose of the Study:
- Evaluate how sample size and along-tract resolution affect tractometry.
- Assess detection of dementia- and amyloid-related effects.
- Optimize study design for tractometry research.
Main Methods:
- Tractometry bootstrap analysis.
- Linear-mixed models applied to diffusion tensor imaging (DTI) metrics.
- Systematic evaluation of sample size and along-tract resolution.
Main Results:
- Coarser segments increase sensitivity and mean effect sizes.
- Finer segments yield higher peak effect sizes, showing localized effects.
- Dementia effects are widespread; amyloid effects are subtle and localized.
Conclusions:
- Tractometry offers spatial specificity for detecting fine-scale effects.
- Study design must be tailored to research questions for optimal efficiency.
- Sample size and resolution choices impact interpretability and detection of neurodegenerative changes.
