Diffusion tensor imaging of white matter tract evolution over the lifespan

Area of Science:

• Neuroimaging
• Developmental Neuroscience
• Aging Research

Background:

• Diffusion tensor imaging (DTI) is crucial for understanding brain structure changes during development and aging.
• Lifespan studies connecting these processes are rare, especially those including both children and the elderly.

Purpose of the Study:

• To investigate microstructural changes in 12 major white matter tracts across the human lifespan using DTI tractography.
• To model age-related changes in fractional anisotropy (FA) and mean diffusivity (MD) and identify regional differences.

Main Methods:

• Utilized DTI tractography on 403 healthy individuals aged 5-83 years.
• Applied Poisson fits to model changes in FA and MD across the entire age span for 12 major white matter tracts.
• Analyzed the influence of tract volume on FA and MD trajectories.

Main Results:

• Significant age-related changes in FA and MD were observed across all investigated white matter tracts.
• FA increased during childhood/adolescence, peaked in adulthood (20-42 years), and then declined.
• MD exhibited an inverse pattern, decreasing to a minimum in adulthood (18-41 years) before increasing later in life.
• Regional variations in maturation and degradation timing were evident, with corpus callosum and fornix showing early reversals.

Conclusions:

• This study provides comprehensive normative data on age-related white matter microstructural changes from childhood to old age.
• Observed FA changes linked to perpendicular diffusivity suggest alterations in myelination and/or axonal density.
• The findings are valuable for future research on white matter development and pathology in various diseases and conditions.