Articles: brain.
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Multicenter Study
Reducing between scanner differences in multi-center PET studies.
This work is part of the multi-center Alzheimer's Disease Neuroimaging Initiative (ADNI), a large multi-site study of dementia, including patients having mild cognitive impairment (MCI), probable Alzheimer's disease (AD), as well as healthy elderly controls. A major portion of ADNI involves the use of [(18)F]-fluorodeoxyglucose (FDG) with positron emission tomography (PET). The objective of this paper is the reduction of inter-scanner differences in the FDG-PET scans obtained from the 50 participating PET centers having fifteen different scanner models. ⋯ Correction factors obtained from phantom studies were applied to 95 scans from normal control subjects obtained from the participating sites. The high frequency correction reduced differences similar to the phantom studies. However, the low frequency correction did not further reduce differences; hence further refinement of the procedure is necessary.
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BMC medical imaging · May 2009
Multicenter StudyProspective multi-centre Voxel Based Morphometry study employing scanner specific segmentations: procedure development using CaliBrain structural MRI data.
Structural Magnetic Resonance Imaging (sMRI) of the brain is employed in the assessment of a wide range of neuropsychiatric disorders. In order to improve statistical power in such studies it is desirable to pool scanning resources from multiple centres. The CaliBrain project was designed to provide for an assessment of scanner differences at three centres in Scotland, and to assess the practicality of pooling scans from multiple-centres. ⋯ Our results indicate the development of scanner specific priors for SPM can assist in pooling of scan resources from different research centres. This can facilitate improvements in the statistical power of quantitative brain imaging studies.
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Brain injury : [BI] · Mar 2009
Multicenter StudyThe relation between Glasgow Coma Scale score and later cerebral atrophy in paediatric traumatic brain injury.
To examine initial Glasgow Coma Scale (GCS) score and its relationship with later cerebral atrophy in children with traumatic brain injury (TBI) using Quantitative Magnetic Resonance Imaging (QMRI) at 4 months post-injury. It was hypothesized that a lower GCS score would predict later generalized atrophy. As a guide in assessing paediatric TBI patients, the probability of developing chronic cerebral atrophy was determined based on the initial GCS score. ⋯ GCS is a commonly used measure of injury severity. It has proven to be a prognostic indicator of cognitive recovery and functional outcome and is also predictive of later parenchymal change.
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Multicenter Study Comparative Study Controlled Clinical Trial
Sample sizes for brain atrophy outcomes in trials for secondary progressive multiple sclerosis.
Progressive brain atrophy in multiple sclerosis (MS) may reflect neuroaxonal and myelin loss and MRI measures of brain tissue loss are used as outcome measures in MS treatment trials. This study investigated sample sizes required to demonstrate reduction of brain atrophy using three outcome measures in a parallel group, placebo-controlled trial for secondary progressive MS (SPMS). ⋯ SIENA and central cerebral volume are feasible outcome measures for inclusion in placebo-controlled trials in secondary progressive multiple sclerosis.
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Critical care medicine · Nov 2008
Multicenter StudyFrom laboratory science to six emergency medical services systems: New understanding of the physiology of cardiopulmonary resuscitation increases survival rates after cardiac arrest.
The purpose of this study is to: 1) describe a newly mechanism of blood flow to the brain during cardiopulmonary resuscitation using the impedance threshold device in a piglet model of cardiac arrest, and 2) describe the survival benefits in humans of applying all of the highly recommended changes in the 2005 guidelines related to increasing circulation during cardiopulmonary resuscitation, including use of the impedance threshold device, from six emergency medical services systems in the United States. ⋯ Use of the impedance threshold device in piglets increased carotid blood flow and coronary and cerebral perfusion pressures and reduced intracranial pressure during the decompression phase of cardiopulmonary resuscitation at a faster rate than controls, resulting in a longer duration of time when intracranial pressures are at their nadir. Patients in six emergency medical services systems treated with the impedance threshold device together with the renewed emphasis on more compressions, fewer ventilations, and complete chest wall recoil had a nearly 50% increase in survival rates after out-of-hospital cardiac arrest compared with historical controls.