A tract-specific framework for white matter morphometry combining macroscopic and microscopic tract features.

Area of Science:

• Neuroimaging
• Biomedical Engineering
• Neuroscience

Background:

• Diffusion tensor imaging (DTI) is crucial for studying white matter in healthy and diseased brains.
• Current DTI methods primarily use diffusivity measures to assess white matter microstructure.
• A gap exists in analyzing white matter morphometry at both macroscopic and microscopic levels.

Purpose of the Study:

• To present a novel tract-specific framework for examining white matter morphometry.
• To integrate macroscopic and microscopic analyses for a more complete characterization of white matter.
• To demonstrate the framework's utility in quantifying white matter atrophy in Amyotrophic Lateral Sclerosis (ALS).

Main Methods:

• Utilizing skeleton-based modeling of white matter fasciculi with continuous medial representation.
• Defining and measuring white matter thickness as a macroscopic feature.
• Combining macroscopic thickness with existing microscopic DTI-derived features.

Main Results:

• The framework provides a natural definition of white matter thickness for cross-subject comparison.
• Macroscopic thickness complements existing microstructural analyses.
• The combined approach offers a more complete characterization of white matter atrophy in ALS compared to microscopic features alone.

Conclusions:

• The novel framework enables tract-specific examination of white matter morphometry at macro and micro scales.
• Integrating macroscopic thickness with microscopic features enhances the characterization of neurodegenerative diseases.
• This approach provides a more comprehensive understanding of white matter changes in conditions like ALS.