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1. 发明授权

US4633178A Process for the excitation of a sample for NMR tomography 失效
标题翻译：用于NMR层析成像的样品激发过程
公开(公告)号：US4633178A
公开(公告)日：1986-12-30
申请号：US723807
申请日：1985-04-16
申请人： Bernhard Strobel , Dieter Ratzel
发明人： Bernhard Strobel , Dieter Ratzel
IPC分类号： A61B10/00 , A61B5/055 , G01R33/48 , G01R33/561 , G01R33/20
CPC分类号： G01R33/5615 , G01R33/5617
摘要： The use of longer 180.degree. pulse sequences for the generation of spin echos is made possible according to the invention during NMR tomography using the 2d-Fourier transformation process in that the phase position and, thus, the sense of rotation of the 180.degree. pulses is reversed after every two pulses. The mirror images which appear otherwise when using the known 180.degree. pulse sequences, e.g. the Carr-Purcell-Gill-Meiboom pulse sequence, are avoided by this measure.
摘要翻译：根据本发明，在使用二维傅立叶变换处理的NMR层析成像中，使用较长的180度脉冲序列来产生自旋回波是可能的，因为相位位置，因此180°脉冲的旋转方向为每两个脉冲后反转。当使用已知的180°脉冲序列时出现的镜像，例如， Carr-Purcell-Gill-Meiboom脉冲序列被这种措施所避免。

2. 发明授权

US5248942A Method of exciting a sample for NMR tomography 失效
标题翻译：提取核磁共振成像样品的方法
公开(公告)号：US5248942A
公开(公告)日：1993-09-28
申请号：US795510
申请日：1991-11-21
申请人： Dieter Ratzel , Erich Treiber , Bernhard Strobel
发明人： Dieter Ratzel , Erich Treiber , Bernhard Strobel
IPC分类号： G01R33/561
CPC分类号： G01R33/561
摘要： In particular with 3D tomography, it is necessary to acquire a large number of individual spectra. Therefore it is advisable to reduce the time needed for the acquisition of a single spectrum without loosing too much in signal-to-noise ratio. To a significant extent, this time is determined by the relaxation time of the spins. Prior to each excitation a significant quantity of these spins have to return into their equilibrium (z-direction of the homogeneous magnetic field) in order to create a usable signal with the next excitation. For spins with long relaxation times T.sub.2 this time can be reduced by a -90.degree. pulse 12 that coincides with the center of the last spin echo 9 with appropriate application of the gradient fields. This -90.degree. pulse returns the x-y magnetization that exists in the x-y plane into the z-direction. The diagnostic relevance can be significantly increased by such a procedure.
摘要翻译：特别是通过3D断层摄影，需要获取大量的单个光谱。因此，建议减少采集单个频谱所需的时间，而不会使信噪比过大。在很大程度上，这个时间是由旋转的松弛时间决定的。在每次激发之前，大量的这些旋转必须返回到它们的平衡（均匀磁场的z方向），以便产生具有下一个激励的可用信号。对于长松弛时间T2的自旋，此时可以通过适当应用梯度场而与最后自旋回波9的中心一致的-90°脉冲12减小。该-90°脉冲将x-y平面中存在的x-y磁化返回到z方向。通过这种程序可以显着增加诊断相关性。

3. 发明授权

US4697148A Process for the excitation of a sample for NMR tomography 失效
标题翻译：用于NMR层析成像的样品激发过程
公开(公告)号：US4697148A
公开(公告)日：1987-09-29
申请号：US723808
申请日：1985-04-16
申请人： Bernhard Strobel , Dieter Ratzel
发明人： Bernhard Strobel , Dieter Ratzel
IPC分类号： A61B10/00 , A61B5/055 , G01R33/48 , G01R33/561 , G01R33/20
CPC分类号： G01R33/5615 , G01R33/5617
摘要： The use of longer 180.degree. pulse sequences for the generation of spin echos is made possible according to the invention during NMR tomography using the 2d-Fourier transformation process in that the phase coding gradient between each pair of 180.degree. pulses is switched on in such a manner that the dephasing caused between each pair of 180.degree. pulses by the phase coding gradient is twice as great as the dephasing caused before the beginning of the first 180.degree. pulse by the phase coding gradient. The mirror images which appear otherwise when using the known 180.degree. pulse sequences, e.g. the Carr-Purcell-Gill-Meiboom pulse sequence, are avoided by this measure.
摘要翻译：根据本发明，使用更长的180°脉冲序列来产生自旋回波是可能的，在使用二维傅立叶变换过程的NMR断层摄影中，每对180°脉冲之间的相位编码梯度在这样的通过相位编码梯度在每对180°脉冲之间引起的去相位的方式是在第一180°脉冲开始之前由相位编码梯度引起的去相位的两倍。当使用已知的180°脉冲序列时出现的镜像，例如， Carr-Purcell-Gill-Meiboom脉冲序列被这种措施所避免。

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