Journal of neurotrauma
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Journal of neurotrauma · Aug 2009
Integrated imaging approach with MEG and DTI to detect mild traumatic brain injury in military and civilian patients.
Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian populations. However, mild (and some moderate) TBI can be difficult to diagnose due to lack of obvious external injuries and because the injuries are often not visible on conventional acute MRI or CT. ⋯ The present study used a neuroimaging approach integrating findings of magnetoencephalography (MEG) and diffusion tensor imaging (DTI), evaluating their utility in diagnosing mild TBI in 10 subjects in whom conventional CT and MRI showed no visible lesions in 9. The results show: (1) the integrated approach with MEG and DTI is more sensitive than conventional CT and MRI in detecting subtle neuronal injury in mild TBI; (2) MEG slow waves in mild TBI patients originate from cortical gray matter areas that experience de-afferentation due to axonal injuries in the white matter fibers with reduced fractional anisotropy; (3) findings from the integrated imaging approach are consistent with post-concussive symptoms; (4) in some cases, abnormal MEG delta waves were observed in subjects without obvious DTI abnormality, indicating that MEG may be more sensitive than DTI in diagnosing mild TBI.
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Journal of neurotrauma · Aug 2009
Predicting outcomes of traumatic brain injury by imaging modality and injury distribution.
Early prediction of outcomes after traumatic brain injury (TBI) is often difficult. To improve prognostic accuracy soon after trauma, we compared different radiological modalities and anatomical injury distribution in a group of adult TBI patients. The four methods studied were computed tomography (CT), magnetic resonance imaging (MRI) with T2-weighted imaging (T2WI), fluid-attenuated inversion recovery (FLAIR) imaging, and susceptibility weighted imaging (SWI). ⋯ In addition, T2WI and FLAIR imaging most consistently discriminated between good and poor outcomes by zonal distribution. While SWI rarely discriminated by outcome, it was very sensitive to intraparenchymal injury and its optimal use in evaluating TBI is unclear. SWI and other new imaging modalities should be further studied to fully evaluate their prognostic utility in TBI evaluation.
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Journal of neurotrauma · Aug 2009
Cauda equina repair in the rat: part 1. Stimulus-evoked EMG for identifying spinal nerves innervating intrinsic tail muscles.
Cauda equina injuries may produce severe leg and pelvic floor dysfunction, for which no effective treatments exist. We are developing a rat cauda equina injury model to allow nerve root identification and surgical repair. One possible difficulty in implementing any repair strategy after trauma in humans involves the correct identification of proximal and distal ends of nerve roots separated by the injury. ⋯ Correctly identifying the level of origin of that root was more difficult, but for ventral roots this rate still exceeded 90%. Using the rat cauda equina model, we have shown that stimulus-evoked EMG can be used to identify ventral nerve roots innervating tail muscles with a high degree of accuracy. These findings support the feasibility of using this conceptual approach for identifying and repairing damaged human cauda equina nerve roots based on stimulus-evoked recruitment of muscles in the leg and pelvic floor.
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Journal of neurotrauma · Aug 2009
Arachidonyl trifluoromethyl ketone is neuroprotective after spinal cord injury.
In spinal cord injury (SCI), neuronal and oligodendroglial loss occurs as a result of the initial trauma and the secondary damage that is triggered by excitotoxicity, free radicals, and inflammation. There is evidence that SCI ellicits increased cytosolic phospholipase A(2) (cPLA(2)) activity. The cleavage of phospholipids by cPLA(2) leads to release of fatty acids, and in particular arachidonic acid (AA), the metabolites of which have been associated with increased inflammation and oxidative stress. ⋯ The number of surviving neurons and oligodendrocytes was significantly increased in animals treated with the cPLA(2) inhibitor compared to saline controls. The behavioral analysis mirrored the neuroprotective effects and showed that the inhibitor-treated group had better locomotor recovery compared to saline controls. Our results show that AACOCF3 has neuroprotective potential, and support the idea that cPLA(2) is critically involved in acute spinal injury.
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Journal of neurotrauma · Jul 2009
Repeated traumatic brain injury affects composite cognitive function in piglets.
Cumulative effects of repetitive mild head injury in the pediatric population are unknown. We have developed a cognitive composite dysfunction score that correlates white matter injury severity in neonatal piglets with neurobehavioral assessments of executive function, memory, learning, and problem solving. Anesthetized 3- to 5-day-old piglets were subjected to single (n = 7), double one day apart (n = 7), and double one week apart (n = 7) moderate (190 rad/s) rapid non-impact axial rotations of the head and compared to instrumented shams (n = 7). ⋯ In our immature large animal model of TBI, two head rotations produced poorer outcome as assessed by neuropathology and neurobehavioral functional outcomes compared to that with single rotations. More importantly, we have observed an increase in injury severity and mortality when the head rotations occur 24 h apart compared to 7 days apart. These observations have important clinical translation to infants subjected to repeated inflicted head trauma.