Diffusion tensor characteristics of gyrencephaly using high resolution diffusion MRI in vivo at 7T

Area of Science:

• Neuroimaging
• Human brain anatomy
• Diffusion MRI

Background:

• Human cerebral cortex gyrification expands surface area for neurons but complicates neuroimaging analysis.
• Cortical layer depth varies between gyri and sulci.
• In vivo diffusion imaging reveals radial tensor orientations in cortical fiber architecture.

Purpose of the Study:

• To investigate if diffusion tensor metrics depend on the human cerebral cortex's gyral pattern.
• To map characteristic diffusion tensor patterns across cortical curvature.
• To assess implications for neuroimaging analysis and tractography.

Main Methods:

• High-resolution diffusion-weighted MRI at 7 Tesla.
• Resampling diffusion data to cortical and white matter surfaces.
• Averaging diffusion tensor metrics over curvature bins to identify gyral patterns.

Main Results:

• Diffusivity, anisotropy, and radiality varied significantly with cortical curvature.
• Maximal radiality was observed in intermediate cortical layers near the gyrus crown.
• Tensor orientations shifted from radial to tangential in deep cortical and white matter layers within sulci.

Conclusions:

• Cortical diffusion tensor metrics are dependent on the gyral pattern.
• Analysis of cortical diffusion data must account for gyral folding.
• Tractography may be biased towards the gyral crown, necessitating careful interpretation.