J P Coles

..To review the techniques for imaging cerebral blood flow and metabolism following injury to the brain...

..Future developments with such imaging techniques should improve understanding of the pathophysiology of brain injury and provide data that should improve management and prediction of functional outcome...

..The objective of this study was to assess the relationship between optic nerve sheath diameter (ONSD), as measured using MRI, and ICP...

..To examine the evidence of regional cerebral ischemia after traumatic brain injury...

..To investigate the effect of hyperventilation on cerebral blood flow in traumatic brain injury...

..To determine whether hyperventilation exacerbates cerebral ischemia and compromises oxygen metabolism (CMRO2) following closed head injury...

..New modelling and analytical approaches have been developed...

..Our data suggest that the response of pressure reactivity to hyperventilation is heterogeneous. This could be due to hyperventilation-induced changes in cerebral metabolism, or the change in CPP...

..At a voxel-based level, however (and in common with ischaemic stroke), the extent of irreversible tissue damage cannot be accurately predicted by early abnormalities of any single physiological variable...

..Further observations are required with regions of interest (microdialysis catheters positioned) adjacent to mass lesions notably contusions...

..To directly compare the cerebrovascular effects of norepinephrine and dopamine in patients with acute traumatic brain injury...

..We investigated the ability of pre-hyperventilation ICP and cerebrospinal compensatory reserve to predict the reduction in ICP achievable with moderate hyperventilation in head injured patients...

..We have used a step increase in target plasma propofol concentration in head injured patients to explore flow-metabolism coupling in these patients...

..This technique holds promise for examining disease progression, and may help define therapeutic windows for the treatment of diffuse brain injury...

..Our results suggest that the ischemic level of brain tissue oxygen may lie at a level below 14 mm Hg (1.8 kPa); however, the data do not allow us to be more specific...

..Cerebrovascular autoregulation is frequently measured in head-injured patients. We attempted to validate 4 bedside methods used for assessment of autoregulation...

..9 kPa resulted in a significant elevation of the OEF, in association with a reduction in glucose, but no significant elevation in the L/P ratio or glutamate...

..It also remains unclear whether CPP values below 65 mmHg can be safely used in this population. Clarification of the significance of a reduction in CMRO2 and neuronal electrical function will require further study...

..Conclusive evidence of cerebral ischemia following head injury has been elusive. We aimed to use (15)O and (18)Fluorodeoxyglucose positron emission tomography (PET) to investigate pathophysiological derangements following head injury...

..Pericontusional oedema on computed tomography was associated with lower absolute values of CBF and CBV but did not differ from nonoedematous tissue in the relative response to CPP elevation...

..Such pathophysiological derangements may result in selective neuronal loss and impact on functional outcome...

..The ischemic burden represented by this "traumatic penumbra" is poorly detected by bedside clinical monitors and has significant associations with outcome...

..We conclude that this technique is a valid and useful tool for quantifying ischemic burden after traumatic brain injury...

..In addition, the airway pressure generated by the valves was not affected by the magnetic field. We conclude that the tested system can be safely used in a 3 Tesla magnetic resonance environment...

..To determine the effect of normobaric hyperoxia on cerebral metabolism in patients with severe traumatic brain injury...

..Such functional improvements may be of immense importance to patients and require formal neurocognitive assessments to discriminate improvements...

..Cerebral edema is a common sequelum post traumatic brain injury (TBI). Quantification of the apparent diffusion coefficient (ADC) using diffusion tensor imaging (DTI) may help to characterize the pathophysiology of brain swelling...

..In particular, we aimed to determine the fate of glucose in terms of differential metabolism to pyruvate and lactate...

..The ability to detect such damage in vivo may have important implications for patient management, patient selection for trials, and to help understand complex neurocognitive pathways...

..To compare the effects of a cerebral perfusion pressure (CPP) intervention achieved with dopamine and norepinephrine after severe head injury...

..To present an integrated imaging solution for analysis of such datasets and report on its use in practice...

..To use a range of techniques to explore diffusion limitation as a mechanism of cellular hypoxia in the setting of head injury...

..While ideally each centre should develop its own bank of such data, the figures provided will allow initial generic approximations of sample size for such studies...

..Large propofol doses may increase the injured brain's vulnerability to secondary insults...

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..62 +/- 3.89 vs. 18.0 +/- 15.18 min, P = 0.015). CONCLUSION: Remifentanil appears to be a comparable opioid to fentanyl when supplementing isoflurane/nitrous oxide anaesthesia for carotid endarterectomy...

..Investigation of these relations requires quantitative measures of cerebral blood flow and CMRO(2), to allow assessment of oxygen supply and demand relations...

..Although the system is MR compatible and produces generally acceptable imaging even at 3 Tesla, there is significant degradation of image quality during gradient echo sequences...

..Understanding the anatomy and extent of brainstem injury, as well as its relationship to supratentorial abnormalities, will facilitate a more accurate use of early MRI as a prognostic tool and assist in the counseling of families...

..That is, in the authors' system, it can be safely used with the transmit-and-receive head coil, but when using the transmit body coil the transducer wire must be coiled into concentric loops outside of the receive-only head coil...

..We investigated the time-course of changes in middle cerebral artery mean flow velocity (FVm) and intracranial pressure (ICP) in head-injured patients during sustained moderate reductions in arterial partial pressure of CO(2) (PaCO(2))...