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Updated: May 12, 2026
Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury
Published on: August 14, 2019
Evaluating the Influence of Injury-Induced Microstructural Variations on the Efficacy of a Diffusion MRI-Derived Axon
Hannah E Alderson1,2, Chaoqi Mu1,2,3, Li Min Chen1,2,3
1Vanderbilt University, Department of Biomedical Engineering, Nashville, Tennessee, USA.
Purpose:
To investigate the utility of a recently demonstrated diffusion MRI derived axon diameter surrogate measure (∆D⟂) under pathologic conditions induced by a spinal cord injury model.
Methods:
Contusion injuries were performed on the thoracic-lumbar spinal cord of adult male rats. Eight weeks post-injury, rats were sacrificed and their spinal cords imaged by MRI and then scanning electron microscopy (SEM). Relationships between the difference in radial diffusivity with diffusion time (∆D⟂) as well as longitudinal relaxometry based metrics and effective axon diameter from SEM were evaluated across regions of interest in slices 2-5 mm away from the injury epicenter.
Results:
∆D⟂ correlated strongly with histology derived effective axon diameter, while bound pool fraction and T1 of the free proton pool (T1f) had no significant correlations with effective axon diameter. A significant relationship was found between T1f and ∆D⟂ across slices.
Conclusion:
In the context of contusion injured rat spinal cords, ∆D⟂ serves as a robust surrogate for axon diameter and provides complementary information to longitudinal relaxometry derived metrics.
