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Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging
Published on: November 8, 2012
Absolute eigenvalue diffusion tensor analysis for human brain maturation
Yuji Suzuki1, Hitoshi Matsuzawa, Ingrid L Kwee
1Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata 951-8585, Japan.
NMR in Biomedicine
|December 4, 2003
Summary
Brain maturation significantly decreases white matter eigenvalues. This decline, particularly in smaller eigenvalues, drives the increase in fractional anisotropy during development.
Area of Science:
- Neuroimaging
- Biophysics
- Developmental Neuroscience
Background:
- White matter integrity is crucial for brain function and develops significantly from childhood to adulthood.
- Diffusion tensor imaging (DTI) measures water diffusion to probe white matter microstructure.
- Eigenvalues of the diffusion tensor provide quantitative insights into white matter properties.
Purpose of the Study:
- To investigate the developmental changes in absolute eigenvalues of the white matter diffusion tensor.
- To understand how these eigenvalue changes relate to fractional anisotropy (FA) during brain maturation.
Main Methods:
- Diffusion tensor imaging (DTI) was performed on a 3.0 T magnetic resonance (MR) system.
- Absolute eigenvalues (λ1, λ2, λ3) were calculated for white matter in two age groups: early developmental (1-10 years) and young adult (18-34 years).
- Fractional anisotropy (FA) was computed as a relative index of white matter integrity.
Main Results:
- All three eigenvalues (largest and two smaller ones) showed a significant decrease with brain maturation.
- The rate of decline was substantially higher for the two smaller eigenvalues compared to the largest eigenvalue.
- This differential decline resulted in an increase in fractional anisotropy (FA) during development.
Conclusions:
- The increase in white matter anisotropy with maturation is primarily driven by a significant reduction in the smaller eigenvalues.
- This pattern suggests a decrease in extra-axonal water and an increase in intra-axonal diffusivity during myelination.
- These microstructural changes reflect the dynamic processes occurring within the axonal environment during brain development.
