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Updated: Mar 18, 2026
Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury
Published on: August 14, 2019
Monitoring Ischemic Cerebral Injury in Spontaneously Hypertensive Rats by Diffusion Tensor Imaging
Gregory C Kujoth1, Gabriel F Neves, Ulas Cikla
1University of Wisconsin, School of Medicine and Public Health, Department of Neurological Surgery, Madison, WI, USA.
Aim:
We have applied diffusion tensor imaging (DTI) to interrogate microstructural changes in white matter integrity in a widely used middle cerebral artery occlusion (MCAO) model of cerebral ischemia.
Material And Methods:
We performed ex vivo DTI 35 days after 60 minutes transient focal ischemia in male spontaneously hypertensive rats and generated fractional anisotropy (FA), mean, axial and radial diffusivity maps. Regions of interest corresponding to external capsule (EC), corpus callosum (CC) and internal capsule (IC) were compared among sham and stroked rats. We compared tractographic projections of white matter fiber patterns and examined white matter integrity by Luxol fast blue histological analysis. We also determined infarct lesion volumes at 24 hours post-ischemia by T2-weighted magnetic resonance imaging (MRI) or at 35 days by histological staining with cresyl violet.
Results:
We found alterations in EC and IC, but not CC, as represented by decreased FA and increased mean, axial and radial diffusivities. The size of the ischemic lesion detected subacutely by T2-weighted MRI or at 35 days by histological staining correlated with the decline in FA in the affected structures. Tractography revealed disruption of fiber trajectories through the EC and reorientation of fibers within the caudate/putamen of rats subjected to MCAO. Similarly, loss of white matter integrity in the EC and increased white matter density in the caudate/putamen along the infarct border zone was evidenced by Luxol fast blue staining.
Conclusion:
Diffusion tensor imaging therefore allows for monitoring of white matter injury and reorganization in hypertensive rats.
Insights
Diffusion tensor imaging (DTI) reveals white matter damage and reorganization after middle cerebral artery occlusion (MCAO) in rats. This technique monitors microstructural changes in the brain
Area of Science:
- Neuroscience
- Radiology
- Biomedical Engineering
Background:
- Cerebral ischemia, induced by middle cerebral artery occlusion (MCAO), causes significant white matter damage.
- Assessing microstructural white matter integrity post-stroke is crucial for understanding recovery and developing therapies.
Purpose of the Study:
- To apply diffusion tensor imaging (DTI) to investigate white matter microstructural changes in a rat model of cerebral ischemia (MCAO).
- To correlate DTI findings with lesion volume and histological assessments of white matter integrity.
Main Methods:
- Ex vivo DTI was performed 35 days after transient focal ischemia in spontaneously hypertensive rats.
- Fractional anisotropy (FA) and diffusivity maps were generated for regions including the external capsule (EC), corpus callosum (CC), and internal capsule (IC).
- Tractography, histological analysis (Luxol fast blue), and MRI/histological infarct volume measurements were utilized.
Main Results:
- Decreased FA and increased diffusivity were observed in the EC and IC, indicating white matter damage.
- Lesion volume correlated with FA decline in affected white matter tracts.
- Tractography showed disrupted EC fibers and altered fiber orientation in the caudate/putamen; histology confirmed white matter loss and density changes.
Conclusions:
- DTI is effective in monitoring white matter injury and adaptive reorganization following ischemic stroke in a rat model.
- These findings highlight DTI's potential for tracking microstructural brain changes in stroke research.
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