Browsing by Subject "mild traumatic brain injury (mTBI)"

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    Hybrid Diffusion Imaging to Detect Acute White Matter Injury after Mild TBI
    (Office of the Vice Chancellor for Research, 2016-04-08) Mustafi, Sourajit M.; Kodiweera, Chandana; Flashman, Laura A.; McAllister, Thomas W.; Wu, Yu-Chien
    Introduction: In the present study we used multi-shell Hybrid Diffusion Imaging (HYDI) to study white matter changes in the acute stage of mild traumatic brain injury (mTBI). Non-parametric diffusion analysis, q-space imaging as well as parametric analyses including conventional DTI and novel neurite orientation dispersion and density imaging (NODDI) were used to analyze the HYDI data. Method: Nineteen mTBI patients and 23 trauma-controlled subjects were recruited from the Emergency Department. Participants received T1W SPGR and HYDI in a Philips 3T Achieve TX scanner with 8-channel head coil and SENSE parallel imaging. The diffusion-weighting (DW) pulse sequence scan-time was about 24 min similar to (1). Results: Forty-eight WM ROIs were defined in the standard MNI space by intersecting subjects’ mean WM skeleton with WM atlas of Johns Hopkins University (JHU) ICBM-DTI-81(2). Linear model analysis was used to test the significance of diffusion metrics between mTBI and trauma-controlled groups with gender and age as covariates (model 3 in Table 1). Maps of DTI, q-space and NODDI diffusion metrics of an mTBI subject are shown in Figure 1. Among various diffusion metrics, only the NODDI derived parenchymal axonal density (Vic) was sensitive to mTBI with significant decreases in 60% of WM ROIs (Table 1). The mTBI subjects had an approximately 4% decrease in Vic. The affected WM tracts concentrated on pyramidal tracts and its cortical projections (bilateral corona radiatae). Most of the cerebella related tracts and hippocampal tracts are spared. Conclusion: HYDI and its diffusion metrics provide insights about microstructural changes of WM in the acute stage of mTBI and may prove useful as a marker of injury.
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    NEROPATHOLOGICAL APPROACH FOR BLAST-WAVE INDUCED MILD BRAIN INJURY
    (Office of the Vice Chancellor for Research, 2012-04-13) Meece, Callie; Chen, Jinhui; Gao, Xiang
    Veterans of Iraq and Afghanistan are extremely susceptible to complica-tions derived from blast-wave induced mild traumatic brain injury (mTBI) sustained from road-side bombs and IEDs. Furthermore, there are 1.5 mil-lion civilian incidences of TBIs annually in the United States, and as many as nearly 75% of them are mTBIs. An mTBI is an important medical concern because it can lead to long-term cognitive, emotional difficulties and behav-ioral disturbances. Neuroimaging with CT or MRI is usually negative. That is why mTBI has been called an “invisible wound.” There are no effective treatments for these disorders, partially due to the fact that the pathological basis leading to neurological disorders are poorly understood. Using a blast-wave injury model, several mice were given injuries similar to those from the front lines. The damaged brains were collected, mounted, stained, and imaged to track the dendrite and spine degeneration, both over all and by type of spine. After quantification, the results showed that the injured brain is intact without showing dramatic lesion or cell death, however, when we further assessed the morphologies of the spared neurons by using Golgi staining to visualize the individual neurons including their processes and spines in a very high resolution, we found that the dendrites of the spared neurons in the injured cortex demonstrated dramatic swelling with beading, a hallmark of dendritic injury, and there was a significant decrease in the number of mature (mushroom) spines, as well as a significant decrease in the overall number of spines. The function of the central nervous system critically relies on the synaptic connection from the different neurons be-tween the spines. The widespread synapse loss disrupts neural circuitry fol-lowing mTBI and will certainly contribute to neurological disorders. Our re-sults showed that mild blast-wave induced injury led to extensive dendrite degeneration and synapse reduction in the cortex in an animal model. This experimental study sheds light on the neuropathology of mild TBI in humans, and suggests that neurodegeneration may be a novel target for developing diagnostic methods and therapeutic approaches for mTBI in the future.