Related Experiment Video
Updated: Apr 18, 2026
Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury
Published on: August 14, 2019
Diffusional kurtosis and diffusion tensor imaging reveal different time-sensitive stroke-induced microstructural
Rachel A Weber1, Edward S Hui1, Jens H Jensen1
1From the Department of Neurosciences (R.A.W., M.F.F., J.A.H., D.L.A.), Center for Biomedical Imaging (J.H.J., X.N., M.F.F., J.A.H., D.L.A.), Department of Radiology and Radiological Science (J.H.J., X.N., M.F.F., J.A.H.), and Health Sciences and Research, College of Health Professions (D.L.A.), Medical University of South Carolina, Charleston; and Department of Diagnostic Radiology, University of Hong Kong, Pokfulam, Hong Kong (E.S.H.).
Background And Purpose:
Diffusion MRI is a promising, clinically feasible imaging technique commonly used to describe white matter changes after stroke. We investigated the sensitivity of diffusion MRI to detect microstructural alterations in gray matter after sensorimotor cortex stroke in adult male rats.
Methods:
The mean diffusivity (MD) and mean kurtosis of perilesional motor cortex were compared with measures in the contralesional forelimb area of sensorimotor cortex at 2 hours, 24 hours, 72 hours, or 25 days after surgery. MD and mean kurtosis were correlated to the surface densities of glia, dendrites, and axons.
Results:
Perilesional mean kurtosis was increased at 72 hours and 25 days after stroke, whereas MD was no longer different from contralesional sensorimotor cortex at 24 hours after stroke. There was a significant increase in the density of glial processes at 72 hours after stroke in perilesional motor cortex, which correlated with perilesional MD.
Conclusions:
These data support that mean kurtosis and MD provide different but complimentary information on acute and chronic changes in perilesional cortex. Glia infiltration is associated with pseudonormalization of MD in the perilesional motor cortex at 72 hours after lesion; however, this association is absent 25 days after lesion. These data suggest that there are likely several different, time-specific microstructural changes underlying these 2 complimentary diffusion measures.
Insights
Diffusion MRI detects gray matter changes after stroke. Mean kurtosis and mean diffusivity (MD) offer complementary insights into acute and chronic microstructural alterations, with glia infiltration influencing MD changes.
Area of Science:
- Neuroimaging
- Stroke Research
- Diffusion MRI
Background:
- Diffusion MRI is a clinically feasible technique for assessing white matter changes post-stroke.
- Its sensitivity in detecting gray matter microstructural alterations after stroke requires further investigation.
Purpose of the Study:
- To evaluate the sensitivity of diffusion MRI in detecting gray matter microstructural changes in the perilesional cortex following sensorimotor cortex stroke in rats.
- To compare diffusion MRI metrics (mean diffusivity and mean kurtosis) with glial and axonal densities.
Main Methods:
- Diffusion MRI metrics (mean diffusivity and mean kurtosis) were measured in the perilesional motor cortex at various time points post-stroke.
- These metrics were compared to the contralesional cortex and correlated with glial, dendritic, and axonal densities.
Main Results:
- Perilesional mean kurtosis increased at 72 hours and 25 days post-stroke.
- Mean diffusivity showed no significant difference at 24 hours but correlated with increased glial processes at 72 hours.
- Glia density changes correlated with mean diffusivity at 72 hours but not at 25 days.
Conclusions:
- Mean kurtosis and mean diffusivity provide distinct, complementary information on acute and chronic perilesional cortex changes.
- Glia infiltration is linked to MD pseudonormalization at 72 hours, an association absent at 25 days.
- Time-specific microstructural changes underlie these diffusion measures, highlighting their complex relationship.
Related Concept Videos
01:17Assessment of Diffusion and Perfusion
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this...
01:15Ischemic Stroke ll: Pathophysiology