One diffusion acquisition and different white matter models: how does microstructure change in human early...

Area of Science:

• Neuroimaging
• Developmental Neuroscience
• Biomedical Engineering

Background:

• Healthy brain development involves complex microstructural changes in white matter during the first three years.
• Diffusion MRI models like DKI and NODDI offer insights into white matter microstructure.
• Limited clinical diffusion data presents challenges for accurate microstructural assessment.

Purpose of the Study:

• To characterize white matter microstructural changes in early childhood using WMTI and NODDI models.
• To compare the findings from WMTI and NODDI in assessing brain development.
• To investigate the feasibility of a less assumption-reliant model for diffusion MRI analysis.

Main Methods:

• Utilized White Matter Tract Integrity (WMTI) metrics from Diffusional Kurtosis Imaging (DKI).
• Employed Neurite Orientation Dispersion and Density Imaging (NODDI) for microstructural analysis.
• Analyzed data from healthy infants during the first three years of development.

Main Results:

• Both WMTI and NODDI demonstrated a non-linear age-related increase in intra-axonal water fraction.
• Increased extra-axonal space tortuosity was observed in key white matter tracts (corpus callosum, internal capsule).
• Intra- and extracellular axial diffusivities remained stable, consistent with myelination and asynchronous fiber development.

Conclusions:

• WMTI and NODDI effectively capture age-dependent white matter microstructural changes in early development.
• Observed changes align with known biological processes of myelination and fiber maturation.
• Understanding model-specific biases is crucial for accurate interpretation of diffusion MRI metrics.