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1. 发明授权

US4535290A Method for measuring the nuclear magnetic resonance for NMR tomography 失效
标题翻译：用于NMR层析成像的核磁共振测量方法
公开(公告)号：US4535290A
公开(公告)日：1985-08-13
申请号：US474699
申请日：1983-03-11
申请人： Hans Post , Dieter Ratzel
发明人： Hans Post , Dieter Ratzel
IPC分类号： A61B10/00 , A61B5/055 , G01R33/48 , G01R33/483 , G01R33/54 , G01R33/56 , G01R33/08
CPC分类号： G01R33/482 , G01R33/56 , G01R33/4838
摘要： In NMR tomography, the nuclear spins of a selected type present in a selected area of a body are selectively excited by applying first a selection gradient field and exciting thereafter the nuclear spins by a HF signal which initially effects a rotation of the nuclear spins situated in a selected plane by an angle .alpha. of less than 90.degree., then a rotation of all selected nuclear spins by 90.degree. and finally again a rotation of the nuclear spins contained in the selected plane by an angle of 90.degree.-.alpha.. As a result thereof, the nuclear spins contained in the selected area have resumed at the end of this excitation their original orientation determined by a homogeneous magnetic field, while nuclear spins located outside this area lie within a plane extending almost vertically thereto. Thereafter, a measuring gradient field may be switched on without disturbing the orientation of the nuclear spins contained in the selected area. With the measuring gradient field switched on, the nuclear spins are now excited by a 90.degree. pulse or usual pulse sequences to produce an induction signal. The measuring processes are carried out in pairs, with the selection gradient field applied, using different excitation signals so that the nuclear spins contained in the selected area are alternately oppositely directed which means that the induction signals generated by them are phase-shifted by 180.degree., whereas the nuclear spins situated outside the selected area are shifted in the same sense so that they supply identical signals, if any.
摘要翻译：在NMR层析成像中，存在于身体的选定区域中的所选类型的核自旋通过首先施加选择梯度场并且随后通过HF信号激励核自旋来选择性地激发，该HF信号最初影响位于所选择的平面的角度α小于90°，然后所有选定的核自旋的旋转90°，最后再次将包含在所选平面中的核自旋旋转90°-α。作为其结果，包含在所选区域中的核自旋在该激发结束时已经恢复，其原始取向由均匀的磁场确定，而位于该区域外部的核自旋位于几乎垂直于其延伸的平面内。此后，可以接通测量梯度场，而不会干扰包含在所选区域中的核自旋的取向。当测量梯度场接通时，核自旋现在被90°脉冲或通常的脉冲序列激发以产生感应信号。测量过程成对地进行，使用选择梯度场，使用不同的激发信号，使得包含在所选区域中的核自旋交替相反，这意味着它们产生的感应信号相移180° 而位于所选区域之外的核自旋以相同的意义移动，使得它们提供相同的信号（如果有的话）。

2. 发明授权

US4694249A Method for recording the nuclear magnetic resonance for use in VNMR tomography 失效
标题翻译：记录用于VNMR层析成像的核磁共振的方法
公开(公告)号：US4694249A
公开(公告)日：1987-09-15
申请号：US815118
申请日：1985-12-27
申请人： Hans Post , Dieter Ratzel , Peter Brunner , Bertold Knuttel
发明人： Hans Post , Dieter Ratzel , Peter Brunner , Bertold Knuttel
IPC分类号： A61B10/00 , A61B5/055 , G01R33/48 , G01R33/50 , G01R33/20
CPC分类号： A61B5/055 , G01R33/50
摘要： For recording the nuclear magnetic resonance in selected areas of a body for the purpose of representing body cross-sections in the form of images (NMR tomography), wherein the nuclear spins of a selected type present in the area of one plane of the body are subjected to a superimposed gradient field varying in the selected cross-sectional plane, and selectively excited, the excitation of the nuclear spins is effected by application of a pulse sequence which induces the nuclear spins to supply at one stage a number of chronologically successive induction signals. The induction signals corresponding to each other in chronolical sequence are then processed to obtain separate sets of image signals so that by one single measurement a sequence of cross-sectional images is obtained which differ from each other by the intensity of the excited nuclear spins which varies according to the relaxation times T.sub.1 or T.sub.2. The fact that all images have been obtained by one and the same measurement provides the possibility to determine the relaxation times T.sub.1 and/or T.sub.2 related to the individual image points and to use them on the one hand for purposes of selective image representation and, on the other hand, for improving the image quality.
摘要翻译：为了在身体的选定区域记录核磁共振，用于以图像形式（NMR层析成像）来表示身体横截面，其中存在于身体的一个平面区域中的选定类型的核自旋是经受在所选截面中变化的叠加梯度场，并且选择性地激发，核自旋的激发通过施加脉冲序列来实现，该脉冲序列诱导核自旋在一个阶段提供多个时间顺序的感应信号。然后处理按时间序列相互对应的感应信号以获得单独的图像信号组，使得通过一次单次测量，获得横截面图像序列，所述序列彼此不同，所述激发的核自旋的强度随着变化根据弛豫时间T1或T2。所有图像都通过一个相同的测量获得的事实提供了确定与各个图像点相关的弛豫时间T1和/或T2的可能性，并且一方面为了选择性图像表示的目的使用它们，并且在另一方面，为了提高图像质量。

3. 发明授权

US4558277A Method for measuring the nuclear magnetic resonance 失效
标题翻译：测量核磁共振的方法
公开(公告)号：US4558277A
公开(公告)日：1985-12-10
申请号：US474555
申请日：1983-03-11
申请人： Hans Post , Dieter Ratzel , Peter Brunner
发明人： Hans Post , Dieter Ratzel , Peter Brunner
IPC分类号： A61B10/00 , A61B5/055 , G01R33/48 , G01R33/483 , G01R33/56 , G01N24/08
CPC分类号： G01R33/4833 , G01R33/56
摘要： For the purpose of limiting NMR spectroscopy to a selected area of a body the said area is prepared by applying first a homogeneous magnetic field passing through the entire body and superimposing thereafter upon the said magnetic field a first magnetic field of identical orientation whose strength varies in a first sense (first field gradient), exciting thereafter all the selected nuclear spins present within the body and in addition, selectively, only the nuclear spins present in a first body plane containing the volume element and extending vertically to the said first field gradient so that the selected nuclear spins contained in this body plane are returned to the direction of the homogeneous magnetic field while the nuclear spins outside this plane receive an orientation differing from the sense of the homogeneous magnetic field. This process is repeated twice, using each time a different gradient field, so that thereafter only the nuclear spins located within the volume element selected by means of the three gradient fields are parallel to the homogeneous magnetic field and can be excited by means of one or more pulses to obtain an oscillation generating an induction signal.
摘要翻译：为了将NMR光谱限制到身体的选定区域，所述区域通过首先施加穿过整个身体的均匀磁场并在此之后叠加在所述磁场上来制备其强度变化的相同取向的第一磁场第一感觉（第一场梯度），然后激发身体内存在的所有选定的核自旋，此外，选择性地仅选择存在于包含体积元素并垂直延伸到所述第一场梯度的第一体平面中的核自旋使得包含在该体平面中的选定的核自旋返回到均匀磁场的方向，而在该平面外的核自旋接收与均匀磁场的感觉不同的取向。该过程重复两次，每次使用不同的梯度场，使得此后只有位于通过三个梯度场选择的体积单元内的核自旋平行于均匀磁场，并且可以通过一个或更多脉冲以获得产生感应信号的振荡。

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