Quantitative T2 mapping as a potential marker for the initial assessment of the severity of damage after traumatic brain injury in rat.
ABSTRACT Severity of traumatic brain injury (TBI) positively correlates with the risk of post-traumatic epilepsy (PTE). Studies on post-traumatic epileptogenesis would greatly benefit from markers that at acute phase would reliably predict the extent and severity of histologic brain damage caused by TBI in individual subjects. Currently in experimental models, severity of TBI is determined by the pressure of applied load that does not directly reflect the extent of inflicted brain injury, mortality within experimental population, or impairment in behavioral tests that are laborious to perform. We aimed to compare MRI markers measured at acute post-injury phase to previously used indicators of injury severity in the ability to predict the extent of histologically determined post-traumatic tissue damage. We used lateral fluid-percussion injury model in rat that is a clinically relevant model of closed head injury in humans, and results in PTE in severe cases. Rats (48 injured, 12 controls) were divided into moderate (mTBI) and severe (sTBI) groups according to impact strength. MRI data (T2, T2*, lesion volume) were acquired 3 days post-injury. Motor deficits were analysed using neuroscore (NS) and beam balance (BB) tests 2 and 3 days post-injury, respectively. Histological evaluation of lesion volume (Fluoro-Jade B) was used as the reference outcome measure, and was performed 2 weeks after TBI. From MRI parameters studied, quantitative T2 values of cortical lesion not only correlated with histologic lesion volume (P<0.001, r=0.6, N=34), as well as NS (P<0.01, r=-0.5, N=34) and BB (P<0.01, r=-0.5, N=34) results, but also successfully differentiated animals with mTBI from those with sTBI 70.6 +/- 6.2 6.2 ms vs. 75.9 +/- 2.6 ms, P<0.001). Quantitative T2 of the lesion early after TBI can serve as an indicator of the severity of post-traumatic cortical damage and neuro-motor impairment, and has a potential as a clinical marker for identification of individuals with elevated risk of PTE.
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ABSTRACT: Prolonged epileptic seizures during status epilepticus (SE) are known to cause neuronal death and lead to brain damage. Lesions in various brain regions can result in memory and cognitive impairment, thus searching of new neuroprotective drugs is important. We evaluated effects of single and chronic administration of ginseng extract on early and late changes in MRI measurements in the rat brain after lithium-pilocarpine SE. Butanol extract of ginseng root cell culture DAN-25 was administered after termination of SE. MRI study of the rat brain was performed 2, 7, and 30 days after SE. High-resolution T2-weighed images and T2-maps were obtained, and total damaged area, hippocampal volume, and T2 relaxation time in several brain structures were calculated. Single administration of ginseng extract attenuated early changes in brain structures found on day 2 after SE. Both single and chronic treatment with ginseng extract decreased brain damage on day 7 after SE. An increase in T2-relaxation time in the hippocampus on day 2 after SE was less prominent in ginseng-treated rats than in saline-treated rats. 30 days after SE, the reduction of hippocampal volume was found both in saline-treated and ginseng-treated rats; however, it was less pronounced in ginseng-treated rats. We conclude that administration of ginseng extract after SE termination reduced brain damage caused by prolonged seizures. Ginseng extract was effective during early period after SE and had a specific protective effect on the hippocampus.Epilepsy research 12/2013; · 2.48 Impact Factor
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ABSTRACT: Mild traumatic brain injury (mTBI) has become an increasing public health concern as subsequent injuries can exacerbate existing neuropathology and result in neurological deficits. This study investigated the temporal development of cortical lesions using magnetic resonance imaging (MRI) to assess two mTBIs delivered to opposite cortical hemispheres. The controlled cortical impact model was used to produce an initial mTBI on the right cortex followed by a second injury induced on the left cortex at 3 (rmTBI 3d) or 7 (rmTBI 7d) days later. Histogram analysis was combined with a novel semi-automated computational approach to perform a voxel-wise examination of extravascular blood and edema volumes within the lesion. Examination of lesion volume 1d post last injury revealed increased tissue abnormalities within rmTBI 7d animals compared to other groups, particularly at the site of the second impact. Histogram analysis of lesion T2 values suggested increased edematous tissue within the rmTBI 3d group and elevated blood deposition in the rm TBI 7d animals. Further quantification of lesion composition for blood and edema containing voxels supported our histogram findings, with increased edema at the site of second impact in rmTBI 3d animals and elevated blood deposition in the rmTBI 7d group at the site of the first injury. Histological measurements revealed spatial overlap of regions containing blood deposition and microglial activation within the cortices of all animals. In conclusion, our findings suggest that there is a window of tissue vulnerability where a second distant mTBI, induced 7d after an initial injury, exacerbates tissue abnormalities consistent with hemorrhagic progression.NeuroImage : clinical. 01/2012; 1(1):18-28.
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ABSTRACT: Mild traumatic brain injury (mTBI) is difficult to detect as the current tools are qualitative, which can lead to poor diagnosis and treatment. The low contrast appearance of mTBI abnormalities on magnetic resonance (MR) images makes quantification problematic for image processing and analysis techniques. To overcome these difficulties, an algorithm is proposed that takes advantage of subject information and texture information from MR images. A contextual model is developed to simulate the progression of the disease using multiple inputs, such as the time post-injury and the location of injury. Textural features are used along with feature selection for a single MR modality. Results from a probabilistic support vector machine using textural features are fused with the contextual model to obtain a robust estimation of abnormal tissue. A novel rat temporal dataset demonstrates the ability of our approach to outperform other state of the art approaches.Image Processing (ICIP), 2012 19th IEEE International Conference on; 01/2012