Quantitative diffusion tensor fiber tracking of age-related changes in the limbic system

Area of Science:

• Neuroimaging
• Neuroscience
• Biomedical Engineering

Background:

• Cerebral white matter integrity declines with age.
• Diffusion Tensor Imaging (DTI) is a key tool for assessing white matter health.
• Understanding age-related changes in specific white matter tracts is crucial.

Purpose of the Study:

• To quantitatively assess age-related changes in diffusivity parameters and fiber characteristics.
• To compare aging effects on the fornix and cingulum white matter tracts.
• To identify which white matter tracts are more vulnerable to aging.

Main Methods:

• Utilized 3 Tesla DTI with a 1.9-mm isotropic resolution on 38 healthy subjects (18-88 years).
• Performed quantitative 3D fiber tracking for fornix and cingulum segmentation.
• Measured fractional anisotropy (FA), mean diffusivity (MD), eigenvalues, number of fibers (NoF), and mean NoF/voxel (FpV).

Main Results:

• The fornix showed moderate correlations between age and diffusivity parameters (FA, MD, eigenvalues).
• Strong negative correlations were found for NoF and moderate for FpV in the fornix.
• The cingulum exhibited no significant correlation for FA and only weak correlations for other parameters with age.
• Significant differences in age-related correlations were observed between the fornix and cingulum for diffusivity and NoF.

Conclusions:

• The fornix demonstrates significant age-related degradation in white matter integrity and fiber characteristics.
• The cingulum appears resistant to age-related white matter changes.
• Quantitative 3D fiber tracking effectively differentiates aging effects on distinct white matter tracts.