Related Experiment Video
Updated: Jul 13, 2026
Development of an Uncomplicated Mild Traumatic Brain Injury Model Modified by Weight-Drop Method and Evidenced by Magnetic Resonance Imaging
Published on: April 11, 2025
Multi-modal magnetic resonance imaging alterations in two rat models of mild neurotrauma
Andre Obenaus1, Michael Robbins, Glen Blanco
1Department of Radiation Medicine, Loma Linda University, Loma Linda, California 92354, USA. aobenaus@dominion.llumc.edu
Abstract:
Magnetic resonance imaging (MRI) is increasingly used in the assessment of the severity and progression of neurotrauma. We evaluated temporal and regional changes after mild fluid percussion (FPI) and controlled cortical impact (CCI) injury using T2-weighted-imaging (T2WI) and diffusion-weighted imaging (DWI) MRI over 7 days. Region of interest analysis of brain areas distant to the injury site (such as the hippocampus, retrosplenial and piriform cortices, and the thalamus) was undertaken. In the hippocampus of CCI animals, we found a slow increase (51%) in apparent diffusion coefficients (ADC) over 72 h, which returned to control values. The hippocampal T2 values in the CCI animals were elevated by 18% over the 7-day time course compared to control, indicative of edema formation. Histological analysis supported the lack of overt cellular loss in most brain regions after mild CCI injury. FPI animals showed a generalized decrease in hippocampal ADC values over the first 72 h, which then returned to sham levels, with decreased T2 values over the same period, which remained depressed at 7 days. Histological assessment of FPI animals revealed numerous shrunken cells in the hippocampus and thalamus, but other regions showed little damage. Increased immunohistochemical staining for microglia and astroglia at 7 days post-injury was greater in FPI animals within the affected brain regions. In summary, traumatic brain injury is less severe in mild CCI than FPI, based on the temporal events assessed with MRI.
Insights
Mild traumatic brain injury (TBI) assessment using MRI revealed distinct patterns. Fluid percussion injury (FPI) showed more severe cellular damage and neuroinflammation than controlled cortical impact (CCI) in rodent models.
Area of Science:
- Neuroscience
- Radiology
- Pathology
Background:
- Magnetic resonance imaging (MRI) is crucial for evaluating neurotrauma severity and progression.
- Understanding temporal and regional changes in the brain after mild traumatic brain injury (TBI) is essential for effective treatment.
Purpose of the Study:
- To compare the temporal and regional changes in the brain following mild fluid percussion injury (FPI) and controlled cortical impact (CCI) using advanced MRI techniques.
- To assess the extent of edema formation and cellular damage in brain regions distant from the primary injury site.
Main Methods:
- Utilized T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) MRI over 7 days in rodent models of mild FPI and CCI.
- Conducted region of interest analysis on specific brain areas, including the hippocampus, retrosplenial cortex, piriform cortex, and thalamus.
- Correlated MRI findings with histological and immunohistochemical analyses to evaluate cellular integrity and neuroinflammation.
Main Results:
- Controlled cortical impact (CCI) induced a transient increase in apparent diffusion coefficients (ADC) and sustained T2 values in the hippocampus, indicating mild edema without significant cell loss.
- Fluid percussion injury (FPI) resulted in decreased hippocampal ADC and T2 values, accompanied by histological evidence of cellular shrinkage in the hippocampus and thalamus.
- FPI exhibited greater microglial and astroglial activation at 7 days post-injury compared to CCI, suggesting a more pronounced inflammatory response.
Conclusions:
- Mild CCI appears to cause less severe TBI than mild FPI, as evidenced by MRI, histological, and immunohistochemical assessments.
- MRI techniques, including T2WI and DWI, are valuable tools for differentiating the severity and pathological characteristics of different mild TBI models.
- The study highlights distinct temporal and regional brain responses to different mild TBI mechanisms, informing future research and clinical management.
