Brain : a journal of neurology
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Steroid sex hormones are potential neuroprotective candidates following CNS injury. All clinical trials to date have examined the effects of oestrogen alone or oestrogen-progestin combination therapy. Experimental studies have suggested that progesterone, in its own right, is a potential neuroprotective agent following acute cerebral injury. ⋯ No studies using models of cerebral ischaemia or TBI assessed efficacy when progesterone was administered at later than 6 h following the onset of cerebral injury. Limited data were available for different groups of animals according to age/hormonal status and the full dose-response relationship was not available in all experimental groups. Although this systematic review provides some supporting evidence for a neuroprotective role of progesterone following either cerebral ischaemia or TBI importantly it highlights areas which need further pre-clinical investigation.
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Diffusion tensor imaging (DTI) has been proposed as a sensitive biomarker of traumatic white matter injury, which could potentially serve as a tool for prognostic assessment and for studying microstructural changes during recovery from traumatic brain injury (TBI). However, there is a lack of longitudinal studies on TBI that follow DTI changes over time and correlate findings with long-term clinical outcome. We performed a prospective longitudinal study of 30 adult patients admitted for subacute rehabilitation following severe traumatic brain injury. ⋯ In the cerebral peduncle and in corpus callosum, lambda(parallel) and lambda(perpendicular) both increased during the scan interval and, particularly in patients with unfavourable outcome, fractional anisotropy remained depressed. No significant DTI parameter changes over time were found in controls, or in CSF of patients. These findings support that DTI is a clinically relevant biomarker in TBI, which may have prognostic value and also might serve as a tool for revealing changes in the neural tissue during recovery.
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Children born prematurely have a high incidence of visual disorders which cannot always be explained by focal retinal or brain lesions. The aim of this study was to test the hypothesis that visual function in preterm infants is related to the microstructural development of white matter in the optic radiations. We used diffusion tensor imaging (DTI) with probabilistic diffusion tractography to delineate the optic radiations at term equivalent age and compared the fractional anisotropy (FA) to a contemporaneous evaluation of visual function. ⋯ The occurrence of mild retinopathy of prematurity did not affect the FA measures or visual scores. We then performed a secondary analysis using tract-based spatial statistics to determine whether global brain white matter development was related to visual function and found that only FA in the optic radiations was correlated with visual assessment score. Our results suggest that in preterm infants at term equivalent age visual function is directly related to the development of white matter in the optic radiations.