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of 33799 results
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AbstractObjective: Magnetic Resonance Imaging (MRI) offers high spatial resolution but has poor sensitivity for visualization of molecular targets. Superparamagnetic iron oxide (SPIO) contrast agents along with antibodies are used to improve MRI sensitivity and...Nov 5, 2018
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AbstractInformation from Magnetic Resonance Imaging (MRI) can be useful for managing infrequent neurological or neuroscientific cases, provided that there are no MRI contra-indications precluding scanning. Here we report on the utility of MRI-based monitoring i...Nov 7, 2018
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Myelination, the elaboration of myelin surrounding neuronal axons, is essential for normal brain function. The development of the myelin sheath enables rapid synchronized communication across the neural systems responsible for higher order cognitive functioning. Despite this critical role, quantitative visualization of myelination in vivo is not possible with current neuroimaging techniques including diffusion tensor and structural magnetic resonance imaging (MRI). Although these techniques offer insight into structural maturation, they reflect several different facets of development, e.g., changes in axonal size, density, coherence, and membrane structure; lipid, protein, and macromolecule content; and water compartmentalization. Consequently, observed signal changes are ambiguous, hindering meaningful inferences between imaging findings and metrics of learning, behavior or cognition. Here we present the first quantitative study of myelination in healthy human infants, from 3 to 11 months of age. Using a ...Jan 12, 2011
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AbstractFunctional magnetic resonance imaging (fMRI) of sleep offers new opportunities to study the brain's functional architecture and its unique signatures during the various behavioral states across the sleep-wake cycle. Unfortunately, previous studies have ...Nov 7, 2018
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AbstractThe biological interpretations of neuroanatomical magnetic resonance imaging (MRI) are challenging. While MRI indices such as cortical thickness (CT) relate to macrostructural organization of the cortical mantle, there is evidence that CT estimates are ...Nov 11, 2021
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AbstractINTRODUCTION With the increased usage of mouse magnetic resonance imaging (MRI) there exists a need for a high resolution MRI mouse brain atlas of normal anatomy for reference. Here we describe a 3 dimensional high resolution MR atlas of the mouse brain...Nov 5, 2007
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AbstractMyelin content can be an important indicator of nerve health and disruption of myelination is associated with several peripheral nerve pathologies, e.g. Charcot-Marie-Tooth Disease. Although extensive investigation has been conducted on axonal pathology...Nov 7, 2018
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AbstractThere have been reports in the literature over the past 20 years that some muscles are not homogeneously activated (i.e. activated as subvolumes) during tasks. During the same period of time magnetic resonance (MR) imaging T2 times have started to be used to measure muscle activity. Certain potential subvolume organizations of motor units could lead to greater variability of T2 time as task effort increases (Prior et al., 1999). Prior et al tested the preceding hypothesis, but did not find any statistically significant differences in whole muscle T2 time variance with increased effort although there was a tendency for variance to increase. The purpose of this study was to look for changes in whole muscle T2 time variance in leg muscles including one purportedly compartmentalized muscle, the lateral gastrocnemius (LG; Segal et al., 1991). Able-bodied subjects carried out concentric plantarflexion contractions against loads equal to 25% and 65% of maximal voluntary contraction (MVC). All subjects had pre and...Nov 10, 2003
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AbstractReal-time in vivo imaging of grafted neural stem progenitor cells (NSPCs) is a significant advance toward understanding the fate of NSPCs after grafting. We have previously demonstrated the utility of bioluminescence imaging system for tracking grafted primary NSPCs in the injured spinal cord. Here we investigated the use of magnetic resonance imaging (MRI) to track the contrast agent-labeled primary NSPCs in the injured spinal cord. Primary NSPCs derived from E14 rodent striatum were labeled with iron oxides particles. Magnetically labeled NSPCs exhibited a similar growth rate to unlabeled cells and did not affect normal cellular differentiation. MRI was performed on an either 11.7-T Bruker Advance Spectrometer or 7.0-T Bruker Pharmascan. in vitro MRI showed that one cluster consisting of 200 single cells led to an MRI contrast sufficient to allow reliable detection. in vivo experiment, spinal cord injury was induced by Multicenter Animal Spinal Cord Injury Study (MASCIS) impactor at T10 level and NSPCs w...Nov 14, 2005
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AbstractBackground: Myelination proceeds sequentially in the developing postnatal human brain. It has been proposed that children with developmental delay (DD) have a temporal delay of this pattern. However, there are no controlled, blinded studies comparing the development of myelination in normal and DD children. Hypothesis: Delays in subcortical myelination accompany DD. Methods: Chart review identified 106 children (36 controls, 70 DD) aged 17-46 months. All children had a brain MRI for evaluation of DD or for another condition (controls). DD was defined as psychomotor retardation diagnosed by clinical examination and/or psychometric testing; only children with idiopathic DD were included. Children with diseases that affect white matter (sickle cell disease, leukodystrophies, etc) or overt intracranial lesions/malformations were excluded. Three board-certified pediatric neuroradiologists who were blinded to the patients’ diagnoses and to each others readings examined axial T2-weighted images. Two scoring syste...Oct 27, 2004