Echo Planar Imaging
Mostrando 1-12 de 15 artigos, teses e dissertações.
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1. Effect of scanner acoustic background noise on strict resting-state fMRI
Functional MRI (fMRI) resting-state experiments are aimed at identifying brain networks that support basal brain function. Although most investigators consider a ‘resting-state’ fMRI experiment with no specific external stimulation, subjects are unavoidably under heavy acoustic noise produced by the equipment. In the present study, we evaluated the influ
Braz J Med Biol Res. Publicado em: 12/04/2013
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2. Aplicação de imagens funcionais por de ressonancia magnetica adquiridas mediante estimulos de memorização no estudo de pacientes com epilepsia do lobo temporal medial e controles : analise de regiões de interesse / Application of functional magnetic resonance images acquired by means of memorization stimuli in the study of patients with both medial temporal lobe epilepsy and controls : regions of interes analysis
Este trabalho teve como objetivo a aquisição, processamento e análise de imagens funcionais por ressonância magnética através da aplicação de estímulos para o estudo de processos relacionados à memória verbal e visual em controles e em pacientes com epilepsia do lobo temporal medial associada a atrofia hipocampal. As imagens foram adquiridas pela
Publicado em: 2008
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3. Study of turbulent flow using Half-Fourier Echo-Planar imaging
The Echo-Planar Imaging technique combined with a partial Fourier acquisition method was used to obtain velocity images for liquid flows in a circular cross-section pipe at Reynolds number of up to 8000. This partial-Fourier imaging scheme is able to generate shorter echo times than the full-Fourier Echo-Planar Imaging methods, reducing the signal attenuatio
Brazilian Journal of Physics. Publicado em: 2006-03
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4. "Development and clinical applications of a high performance radio-frequency/gradient coil integrated system for Magnetic Resonance Imaging in 0.5 Tesla" / "Desenvolvimento e aplicações clínicas de um sistema integrado transdutor/bobinas de gradientes de alto desempenho para obtenção de imagens por ressonância magnética em 0.5 TESLA"
Este trabalho descreve o desenvolvimento de um sistema integrado transdutor/bobinas de gradientes de alto desempenho para Imagens por Ressonância Magnética. Este sistema é composto por um transdutor de radiofreqüência tipo sela e um conjunto de 3 bobinas locais assimétricas. No desenho do transdutor foram otimizados os parâmetros: relação sinal ruí
Publicado em: 2005
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5. Fast acquisition of images with techniques of type Echo Planar Imaging - Implementation of sequences EPI and SEPI / Aquisição rápida de imagens com técnicas tipo Echo Planar Imaging - Implementação das sequências EPI e SEPI.
The objective of this work is the development and implementation of methodologies of images for Nuclear Magnetic Resonance, for reduction of the time of acquisition, since in the conventional clinical examinations this time is very superior to the used one in these sequences, that are of the order of T_ 2 , these sequences is based on the only sweepings of t
Publicado em: 2004
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6. Images by Nuclear Magnetic Resonance: A Modified Version of the EPI Method
It is well known that data accquisition times and image reconstruction procedures in conventional magnetic resonance imaging (MRI) are usually long. For time dependent phenomena, such as sample motion, respiration, blood flow pulsation and others, faster accquision times are desirable to avoid ghosting artifacts. Over the last two decades, a great number of
Brazilian Journal of Physics. Publicado em: 2001-06
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7. Echo-planar magnetic resonance imaging studies of frontal cortex activation during word generation in humans.
Nine subjects were studied by high-speed magnetic resonance imaging while performing language-based tasks. Subjects were asked either to repeat or to generate verbs associated with nouns read by an experimenter while magnetic resonance images were obtained of the left inferior frontal lobe. The echo-planar imaging sequence was used with a gradient echo time
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8. Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation.
Neuronal activity causes local changes in cerebral blood flow, blood volume, and blood oxygenation. Magnetic resonance imaging (MRI) techniques sensitive to changes in cerebral blood flow and blood oxygenation were developed by high-speed echo planar imaging. These techniques were used to obtain completely noninvasive tomographic maps of human brain activity
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9. Imaging of H217O distribution in the brain of a live rat by using proton-detected 17O MRI
Imaging of H217O has a number of important applications. Mapping the distribution of H217O produced by oxidative metabolism of 17O-enriched oxygen gas may lead to a new method of metabolic functional imaging; regional cerebral blood flow also can be measured by measuring the H217O distribution after the injection of 17O-enriched physiological saline solution
The National Academy of Sciences.
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10. The hippocampal formation participates in novel picture encoding: evidence from functional magnetic resonance imaging.
Considerable evidence exists to support the hypothesis that the hippocampus and related medial temporal lobe structures are crucial for the encoding and storage of information in long-term memory. Few human imaging studies, however, have successfully shown signal intensity changes in these areas during encoding or retrieval. Using functional magnetic resonan
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11. Dynamic mapping of the human visual cortex by high-speed magnetic resonance imaging.
We report the use of high-speed magnetic resonance imaging to follow the changes in image intensity in the human visual cortex during stimulation by a flashing checkerboard stimulus. Measurements were made in a 2.1-T, 1-m-diameter magnet, part of a Bruker Biospec spectrometer that we had programmed to do echo-planar imaging. A 15-cm-diameter surface coil was
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12. Sodium-23 magnetic resonance imaging of the eye and lens.
In order to develop a better understanding of cataract and to evaluate the effectiveness of potential drugs, noninvasive techniques must be devised to detect early metabolic changes. As a prelude to these goals, sodium-23 imaging experiments operating at 29.8 MHz (2.7 teslas) were performed on the bovine eye and lens. A spatially localized transverse relaxat