Shimming
Mostrando 1-4 de 4 artigos, teses e dissertações.
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1. Paramagnetic shimming for high-field MRI
The diamagnetism of biological tissues reduces the homogeneity of the magnetic field and may limit the number of samples in multi-sample gradient-recalled echo (GRE) experiments. This study aims to 1) evaluate the magnetic field distortions and signal loss artifacts in GRE images of proximal water samples, and 2) develop a passive shimming device to overcome
Brazilian Journal of Physics. Publicado em: 2009-06
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2. Improving magnetic field homogeneity of a resistive magnet with iron core using passive Shimming method / Homogenização de um magneto resistivo com núcleo de ferro utilizando-se o método de Shimming passivo
Este trabalho consistiu na implementação de um método de homogeneização de campo, denominado shimming passivo. Esse método é caracterizado pela inserção de pequenas peças ferromagnéticas no interior do magneto; a interação destas peças com o campo magnético principal produz campos locais capazes de corrigir inomogeneidades indesejadas, quando
Publicado em: 2004
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3. A high spatial resolution in vivo 1H magnetic resonance spectroscopic imaging technique for the human breast at 3 T
Purpose: The technical challenges that have prevented routine proton magnetic resonance spectroscopic imaging (1H MRSI) examinations of the breast include insufficient spatial resolution, increased difficulties in shimming compared to the brain, and strong lipid contamination at short echo time (TE) at 1.5 T. The authors investigated the feasibility of high
American Association of Physicists in Medicine.
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4. Natural-abundance 13C NMR study of glycogen repletion in human liver and muscle.
Optimizing the surface-coil design and spectral-acquisition parameters has lead to the observation of the 13C NMR natural abundance glycogen signal in man at 2.1 T. Both the human muscle and hepatic glycogen signals can be detected definitively with a time resolution of approximately equal to 13 min. A 1H/13C concentric surface coil was used. The 1H outer co