Age-Related Modifications of Diffusion Tensor Imaging Parameters and White Matter Hyperintensities as Inter-Dependent...

Area of Science:

• Neuroimaging
• Gerontology
• Biomedical Engineering

Background:

• Aging is associated with microstructural White Matter (WM) changes, often studied using Diffusion Tensor Imaging (DTI).
• White Matter Hyperintensities (WMH) are common in older adults but their relationship with DTI changes is not fully understood.
• Few studies have investigated DTI parameters and WMH conjointly in aging.

Purpose of the Study:

• To investigate the effects of aging on DTI parameters in normal-appearing white matter (NAWM) with and without White Matter Hyperintensities (WMH).
• To explore the relationship between the burden of WMH and DTI-derived microstructural changes in NAWM.
• To determine if DTI changes and WMH represent sequential or parallel processes in aging.

Main Methods:

• Acquisition of 21-direction DTI scans from young adults and two age-matched groups of older adults (low-WMH and high-WMH).
• Analysis of DTI parameters including Fractional Anisotropy (FA) and Radial Diffusivity (RD).
• Comparison of DTI parameters between age groups and WMH levels, assessing associations between WMH burden and NAWM DTI values.

Main Results:

• Older adults with WMH showed significant DTI parameter modifications compared to younger adults (decreased FA, increased RD).
• Older adults with high WMH exhibited more pronounced DTI changes in NAWM than those with low WMH.
• In older adults with high WMH, NAWM FA and RD values correlated with WMH burden.

Conclusions:

• DTI changes and WMH are likely inter-dependent processes occurring at different stages of aging.
• DTI modifications may represent an early phase of white matter degeneration.
• WMH appear to develop as a consequence of these earlier, DTI-detectable white matter changes.