发明授权
- 专利标题: Method for improving the signal-to-noise ratio in a nuclear magnetic resonance tomography apparatus
- 专利标题(中): 改进核磁共振成像装置中信号噪声比的方法
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申请号: US565951申请日: 1990-08-10
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公开(公告)号: US5084675A公开(公告)日: 1992-01-28
- 发明人: Hans-Erich Reinfelder , Hubertus Fischer
- 申请人: Hans-Erich Reinfelder , Hubertus Fischer
- 申请人地址: DEX Munich
- 专利权人: Siemens Aktiengesellschaft
- 当前专利权人: Siemens Aktiengesellschaft
- 当前专利权人地址: DEX Munich
- 优先权: EPX89114922.1 19890811
- 主分类号: A61B5/055
- IPC分类号: A61B5/055 ; G01R33/32 ; G01R33/56
摘要:
In the echo planar imaging (EPI) method of operating a nuclear magnetic resonance (magnetic resonance imaging) tomography apparatus, the necessary, rapid switching of gradients having a high amplitude usually cannot be achieved with square-wave gradients, and therefore a read-out gradient having a sinusoidal shape is generally used. Given a chronologically equidistant sampling of the nuclear magnetic resonance signal in the time domain, however, a sampling in the k-space with different rates is present. The bandwidth of the signal is proportional to the sampling rate in the k-space. In the method disclosed herein, bandwidth of a bandpass filter or a low-pass filter in the signal processing circuit for the nuclear magnetic resonance signal is adapted to the time dependent bandwith of the nuclear magnetic resonance signal, i.e., to the sampling rate in the k-space. The bandwidth is increased with increasing sampling rate. The signal-to-noise ratio is noticeably improved.
公开/授权文献
- US5815579A Portable speakers with phased arrays 公开/授权日:1998-09-29
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