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Updated: Aug 11, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Influence of aging on brain gray and white matter changes assessed by conventional, MT, and DT MRI
B Benedetti1, A Charil, M Rovaris
1Department of Neurology, Scientific Institute and University Ospedale San Raffaele, Milan, Italy.
Background:
Conventional MRI can reveal decreases in brain volumes with aging but fails to provide information about the underlying microstructural modifications. Magnetization transfer (MT) and diffusion tensor (DT) MRI can in part overcome these limitations.
Objective:
To investigate the influence of aging on conventional and MT and DT MRI-derived measurements in brain white (WM) and gray (GM) matter.
Methods:
Dual-echo, T1-weighted, MT and DT MR images of the brain were obtained in 89 healthy subjects (age range 11 to 76 years). Normalized GM and WM volumes were measured and MT ratio (MTR) and mean diffusivity (MD) histograms produced for both tissue compartments.
Results:
Normalized brain (r = -0.78), GM (r = -0.75), and WM (r = -0.34) volumes and the number of brain T2 hyperintensities (r = 0.49) were correlated with age. Additionally, all GM MT- and DT-derived parameters also correlated with age (r values ranging from 0.28 to 0.64), whereas only the peak height (ph) of the normal-appearing (NA) WM MD histogram did so (r = -0.34). After correcting for the number of T2 hyperintensities, gender, and the corresponding normalized tissue volumes, only the correlations between age and GM average MD (r = 0.24), GM-MD-ph (r = -0.37), and NAWM-MD-ph (r = -0.29) remained significant. A multivariate regression analysis including both brain tissues variables retained the GM volume (beta = -0.18, SE = 0.02, p < 0.001) and the GM average MD (beta = 45, SE = 19, p = 0.02) as independent predictors of subject's age.
Conclusions:
Brain white matter and gray matter have different vulnerabilities to aging. Microstructural imaging is important to achieve a complete picture of the complex changes occurring in the aging brain.
Insights
Aging affects brain gray matter (GM) and white matter (WM) differently. Advanced MRI techniques like Magnetization Transfer (MT) and Diffusion Tensor (DT) imaging reveal microstructural changes in the aging brain.
Area of Science:
- Neuroimaging
- Radiology
- Gerontology
Background:
- Conventional MRI shows brain volume loss with aging but misses microstructural details.
- Magnetization Transfer (MT) and Diffusion Tensor (DT) MRI offer insights into microstructural changes.
Purpose of the Study:
- To assess aging effects on conventional MRI and MT/DT MRI metrics in brain gray matter (GM) and white matter (WM).
Main Methods:
- Acquired dual-echo, T1-weighted, MT, and DT MR images from 89 healthy individuals (age 11-76).
- Measured normalized GM and WM volumes.
- Generated MT ratio (MTR) and mean diffusivity (MD) histograms for GM and WM.
Main Results:
- Age correlated with brain, GM, and WM volumes, and T2 hyperintensities.
- GM MT and DT parameters correlated with age; only normal-appearing WM MD histogram peak height correlated with age.
- After adjustments, GM average MD and GM/WM MD histogram peak heights remained significant predictors of age.
Conclusions:
- Brain gray and white matter exhibit distinct age-related vulnerabilities.
- Microstructural imaging is crucial for a comprehensive understanding of brain aging.
