Scattering Approach to Diffusion Quantifies Axonal Damage in Brain Injury
- Description
This study demonstrated that time-dependent diffusion MRI can detect subtle axonal changes in brain injury by identifying structural signatures of diffusive dynamics of water along axons. Scattering theory reveal two parameters that determine the diffusive dynamics of water along axons: the average reciprocal cross-section and the variance of long-range cross-sectional fluctuations. This theoretical development allowed the research team to predict diffusion MRI metrics sensitive to axonal alterations over tens of thousands of axons in seconds rather than months of simulations in a male rat model of traumatic brain injury.
For the study, white matter (corpus callosum and cingulum) of five rat brains, two sham-operated rats and three rats with traumatic brain injury, was imaged using 3D electron microscopy. The images were acquired ipsilateral and contralateral to the site of injury, resulting in a total of 20 electron microscopy datasets. Each 3D electron microscopy dataset included thousands of myelinated axons that were evaluated individually to draw the statistical conclusions. In addition, an ex vivo time-dependent diffusion MRI experiment was conducted on two sham-operated rats and three rats with mild traumatic brain injury, sacrificed four weeks post-surgery, to experimentally validate the theoretical predications.
Access
- Restrictions
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Free to All
- Instructions
- Segmentation of white matter microstructure in 3D electron microscopy and axonal morphology and time-dependent diffusion MRI data in brain injury are publicly available at fairdata.fi. The source code of DeepACSON software, Monte Carlo simulator, and source code used to generate the results presented in the paper are publicly available at GitHub.
- Grant Support
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Irma T. Hirschl Trust/Irma T. Hirschl Trust360360/Research Council of Finland323385/Research Council of Finland361370/Research Council of Finland358944/Research Council of Finland