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公开(公告)号：US5113137A
公开(公告)日：1992-05-12
申请号：US579581
申请日：1990-09-10
申请人： Hideaki Koizumi , Koichi Sano , Tetsuo Yokoyama , Kazuya Sukegawa
发明人： Hideaki Koizumi , Koichi Sano , Tetsuo Yokoyama , Kazuya Sukegawa
摘要： There is provided an image noise reduction method for improving the signal-to-noise ratio of an image when observed. The image signal of an identical region is measured twice at different times. Images obtained by respective measurements and seen from an identical visual point are so juxtaposed on an identical plane as to form two sheets. By seeing the two sheets of images with parallax changed directly or through stereo glass, the effective signal components of the images are focused on the same plane whereas only noise components are dispersed in a direction perpendicular to the plane.
摘要翻译： 提供了一种用于在观察时改善图像的信噪比的图像噪声降低方法。 相同区域的图像信号在不同时间测量两次。 通过各自的测量得到的图像和从相同的视点观察到的图像被并置在相同的平面上以形成两张纸。 通过直视或立体玻璃观看视差的两张图像，图像的有效信号分量聚焦在同一平面上，而只有噪声分量在垂直于平面的方向上分散。
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公开(公告)号：US5023553A
公开(公告)日：1991-06-11
申请号：US330835
申请日：1989-03-30
申请人： Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
发明人： Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
CPC分类号： G01R33/5676
摘要： In order to eliminate the degradation of NMR image caused by a body motion due to breathing or the like, one of measured image signals is selected as a reference, correlation is calculated between each measured image signal and the reference, and the image signal is modified on the basis of the value of correlation.
摘要翻译： 为了消除由于呼吸等引起的身体运动引起的NMR图像的劣化，选择测量图像信号之一作为参考，在每个测量的图像信号和参考之间计算相关性，并且图像信号被修改 在相关性的基础上。
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公开(公告)号：US4939462A
公开(公告)日：1990-07-03
申请号：US376216
申请日：1989-07-03
申请人： Akira Maeda , Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
发明人： Akira Maeda , Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
CPC分类号： G01R33/4833
摘要： In order to narrow the dynamic range of an NMR signal and to provide MRI of low cost and high image quality without inducing the distortions of an image other than distortion of phase which can be corrected or the degradations of the measurement accuracies of various parameters, a coil for generating an inhomogeneous magnetic field which varies slowly within region to-be-imaged is added to a coil for generating a static magnetic field of high homogeneity, and current to flow through the former coil is changed so as to control the inhomogeneous magnetic field.
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公开(公告)号：US4724388A
公开(公告)日：1988-02-09
申请号：US869976
申请日：1986-06-02
申请人： Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
发明人： Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
IPC分类号： G01R33/565 , G01R33/20
CPC分类号： G01R33/56518 , G01R33/56563
摘要： In order to measure a static field distribution with one scanning operation and to make image distortion corrections with the static field distribution and a gradient field distribution simultaneously considered, an image is reconstructed using a spin echo signal produced under the condition that a time interval between a 90.degree. pulse and a 180.degree. pulse differs from an interval between the 180.degree. pulse and the time origin of the spin echo signal, the static field distribution is evaluated from the relation of distortions to phase errors free from a phase distortion attributed to the characteristic of a detecting part and a phase distortion attributed to the dynamic characteristic of the gradient field, a relations existing between the spatial distortion and phase distortion of the reconstructed image and a magnetic field distribution including the gradient field is obtained, and the distortion magnitude of the reconstructed image is evaluated from the measured magnetic field distribution.
摘要翻译： 为了通过一次扫描操作测量静态场分布，并且同时考虑静态场分布和梯度场分布进行图像失真校正，使用自旋回波信号来重构图像，该自旋回波信号是在 90°脉冲和180°脉冲与180°脉冲与自旋回波信号的时间原点之间的间隔不同，静态场分布从失真和相位误差的关系来评估，该相位误差不包括归因于特性的相位失真 得到归因于梯度场的动态特性的检测部分和相位失真，获得重建图像的空间失真和相位失真之间存在的关系以及包括梯度场的磁场分布，并且， 从测量的磁场分布评估重建图像 。
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公开(公告)号：US5207222A
公开(公告)日：1993-05-04
申请号：US713316
申请日：1991-06-11
CPC分类号： G01R33/4804
摘要： Based on the relation that the higher the temperature of a portion to be measured, the lower becomes coherence of a nuclear spin at that portion, the present invention measures indirectly the temperature state of the portion to be measured from the change of intensity of NMR signals by utilizing this relationship. A transverse relaxation time is contained as one of the parameters in the relation between the signal intensity and the temperature; hence this transverse relaxation time is determined in advance for the portion to be measured and utilized in for the equation representing their relationship. This application discloses also an invention for determining a blood perfusion rate of the portion to be measured from the temperature data obtained in the manner described above.
摘要翻译： 基于测量部分的温度越高，该部分的核自旋的相关性越低，本发明根据NMR信号的强度的变化间接地测量待测部分的温度状态 通过利用这种关系。 横向弛豫时间作为信号强度与温度之间关系的参数之一; 因此该横向弛豫时间预先被测量的部分用于表示它们的关系的方程式。 本申请还公开了根据以上述方式获得的温度数据来确定待测量部分的血液灌注速率的发明。
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公开(公告)号：US5115812A
公开(公告)日：1992-05-26
申请号：US441972
申请日：1989-11-28
申请人： Koichi Sano , Akira Maeda , Tetsuo Yokoyama , Hideaki Koizumi
发明人： Koichi Sano , Akira Maeda , Tetsuo Yokoyama , Hideaki Koizumi
IPC分类号： G01R33/563 , G01R33/565 , G01R33/567
CPC分类号： G01R33/56316 , G01R33/56509 , G01R33/56563
摘要： To obtain a high quality image at a vascular area at high speed: (1) there is used a pulse sequence which includes a bipolar phase encoding magnetic field, dephases a stationary area, and does not generate the first order moment; (2) phase distortions are estimated from measured data and removed, without incorporating a new function for function fitting; and (3) the relationship between the application timing of a readout gradient magnetic field and the latest application time of the other slice selection and phase encoding magnetic fields is obtained using as its parameter the time T.sub.E from excitation to generation of an echo peak within a measurement signal, and using this relationship, the application timing T.sub.E is obtained which makes minimum the echo peak shift quantity.
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7.发明授权
公开(公告)号：US4996480A
公开(公告)日：1991-02-26
申请号：US418224
申请日：1989-10-06
申请人： Akira Maeda , Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
发明人： Akira Maeda , Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
IPC分类号： G01R33/54 , A61B5/055 , G01R33/32 , G01R33/485 , G01R33/565
CPC分类号： G01R33/56527 , G01R33/485
摘要： A magnetic resonance signal is detected at a plurality of different periods of time in accordance with the phase shift of a plurality of chemical shift components while varying the intensity of a gradient magnetic field with time, a plurality of magnetic resonance signal thus obtained are used for estimating a magnetic resonance signal due to only a predetermined chemical shift component, the phase rotation of the predetermined chemical shift component is corrected in the estimated resonance signal, and further a blur due to chemical shift components other than the predetermined one is corrected to obtain a tomogram formed of only the predetermined chemical shift component. Alternatively, one measured resonance signal is modified by an image reconstruction algorithm peculiar to each of a plurality of chemical shift components, to obtain tomograms corresponding to the chemical shift components.
摘要翻译： 在随时间变化梯度磁场的强度的同时，根据多个化学位移分量的相移，在多个不同的时间段检测磁共振信号，由此得到的多个磁共振信号用于 估计由于只有预定的化学位移分量而产生的磁共振信号，在估计的共振信号中校正预定化学位移分量的相位旋转，并且进一步校正由于除了预定的化学位移分量之外的化学位移分量的模糊以获得 仅由预定的化学位移分量形成的断层图像。 或者，通过对多个化学位移分量中的每一个特有的图像重构算法修改一个测量的共振信号，以获得对应于化学位移分量的断层图像。
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8.发明授权
公开(公告)号：US4901021A
公开(公告)日：1990-02-13
申请号：US262282
申请日：1988-10-25
申请人： Akira Maeda , Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
发明人： Akira Maeda , Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
IPC分类号： G01R33/485 , G01R33/565
CPC分类号： G01R33/485 , G01R33/56527
摘要： A magnetic resonance signal is detected at a plurality of different periods of time in accordance with the phase shift of a plurality of chemical shift components while varying the intensity of a gradient magnetic field with time, a plurality of magnetic resonance signals thus obtained are used for estimating a magnetic resonance signal due to only a predetermined chemical shift component, the phase rotation of the predetermined chemical shift component is corrected in the estimated resonance signal, and further a blur due to chemical shift components other than the predetermined one is corrected to obtain a tomogram formed of only the predetermined chemical shift component. Alternatively, one measured resonance signal is modified by an image construction algorithm peculiar to each of a plurality of chemical shift components, to obtain tomograms corresponding to the chemical shift components.
摘要翻译： 在随时间变化梯度磁场的强度的同时，根据多个化学位移分量的相移，在多个不同的时间段内检测磁共振信号，由此得到的多个磁共振信号用于 估计由于只有预定的化学位移分量而产生的磁共振信号，在估计的共振信号中校正预定化学位移分量的相位旋转，并且进一步校正由于除了预定的化学位移分量之外的化学位移分量的模糊以获得 仅由预定的化学位移分量形成的断层图像。 或者，一个测量的谐振信号通过多个化学位移分量中的每一个特有的图像构造算法进行修改，以获得对应于化学位移分量的断层图像。
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公开(公告)号：USRE34495E
公开(公告)日：1994-01-04
申请号：US725514
申请日：1991-07-03
申请人： Koichi Sano , Tetsuo Yokoyama , Ryuzaburo Takeda , Yasuhiko Ozawa , Shinichi Sato , Hideaki Koizumi
发明人： Koichi Sano , Tetsuo Yokoyama , Ryuzaburo Takeda , Yasuhiko Ozawa , Shinichi Sato , Hideaki Koizumi
IPC分类号： G01F1/716 , G01P5/00 , G01R33/563 , A61B5/055
CPC分类号： G01F1/716 , G01P5/00 , G01R33/56308 , G01R33/56316
摘要： A slice selection gradient magnetic field used in a pulse sequence for generating a spin echo signal is applied in such a fashion that its polarity at the time of a 90.degree. pulse becomes opposite to the one at the time of 180.degree. pulse, in order to expand a dynamic range of blood flow speed measurement. When the blood flow speed contains a component in a slice vertical direction, the gradient magnetic field in the slice vertical direction is adjusted so that the phase changes of two sets of flow encoded pulses contained in the slice vertical direction are opposite to each other.The flow speed in the direction of the readout gradient magnetic field, which is a lateral direction of the slice plane, is purely measured by canceling influences of the flow in the slice vertical direction.
摘要翻译： 施加用于产生自旋回波信号的脉冲序列中的切片选择梯度磁场，使得其在90度脉冲时的极性与180度脉冲时的极性相反，以便 扩大血流速度测量的动态范围。 当血流速度包含切片垂直方向上的分量时，调整切片垂直方向上的梯度磁场，使得包含在切片垂直方向上的两组流动编码脉冲的相位变化彼此相反。 通过消除切片垂直方向上的流动的影响，纯粹地测量作为切片平面的横向的读出梯度磁场的方向上的流速。
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公开(公告)号：US4905699A
公开(公告)日：1990-03-06
申请号：US92303
申请日：1987-09-02
申请人： Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
发明人： Koichi Sano , Tetsuo Yokoyama , Hideaki Koizumi
IPC分类号： A61B5/055
CPC分类号： A61B5/055 , A61B5/7257
摘要： In order to permit the detection of a respiratory motion and an imaging synchronized with the respiration by an NMR imaging apparatus itself without any special hardware, a sequence for detecting the respiratory motion is repeated for a short time immediately before the measurement of an image signal to detect the position and speed of the respiratory motion, and a desired image signal is measured in synchronism with the detected position. Alternatively, the respiratory motion is detected immediately after the measurement of an image signal, and the measured image signal is corrected in accordance with the detected amount to obtain a desired image signal synchronized with the respiration.
摘要翻译： 为了允许通过NMR成像设备本身检测呼吸运动和与呼吸同步的成像，而没有任何特殊的硬件，用于检测呼吸运动的顺序在测量图像信号之前的短时间内被重复到 检测呼吸运动的位置和速度，并且与检测到的位置同步地测量期望的图像信号。 或者，在测量图像信号之后立即检测呼吸运动，并且根据检测到的量校正测量的图像信号，以获得与呼吸同步的期望的图像信号。
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