• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Applied Magnetic Resonance >MR measurement technique of rapidly switched gradient magnetic fields in MR tomography
【24h】

MR measurement technique of rapidly switched gradient magnetic fields in MR tomography

机译：磁共振层析成像中快速切换梯度磁场的MR测量技术

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Gradient eddy currents, induced in the surrounding conductive structures in a magnetic resonance (MR) magnet, are a major problem in MR imaging, in localized MR spectroscopy and in many other MR experiments. We present a comparison of three methods of measuring the gradient time characteristics and the time changes of basic magnetic field B-0 after the gradient is switched off. The methods are based on the selective excitation of a thin layer of the sample and on acquiring the MR signal obtained after the end of the gradient pulse and on the computation of the instantaneous frequency of the signal. At this point, the time gradient characteristic is proportional to the instantaneous frequency of the MR signal, which has a small signal-to-noise ratio. We use the characteristics measured to set the pre-emphasis parameters in a 200 MHz/200 nun MR scanner. From the results obtained by measurement it follows that all methods are convenient for simple and quick characterization of magnetic field gradient in MR tomographic magnets.
机译：在磁共振（MR）磁体周围的导电结构中感应产生的梯度涡流是MR成像，局部MR光谱学和许多其他MR实验中的主要问题。我们比较了三种测量梯度时间特性和梯度关闭后基本磁场B-0随时间变化的方法。该方法基于样品薄层的选择性激发，并基于在梯度脉冲结束后获得的MR信号以及信号瞬时频率的计算。此时，时间梯度特性与MR信号的瞬时频率成正比，而MR信号的信噪比很小。我们使用测得的特性在200 MHz / 200尼姑MR扫描仪中设置预加重参数。从测量获得的结果可以看出，所有方法都可以方便，快速地表征MR断层扫描磁体中的磁场梯度。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号