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

IPC分类号： A61B5/055 ,  G01R33/48 ,  G01R33/54

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.

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.

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。

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。

公开(公告)号：US5275164A

公开(公告)日：1994-01-04

申请号：US386380

申请日：1989-07-28

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 ,  G01R33/56 ,  G01R33/561 ,  G01R33/567 ,  G06T11/00

CPC分类号： G01R33/5673 ,  G01R33/56 ,  G01R33/561

摘要： A method and apparatus for MRI imaging capable of reducing the time between end of measurement and completion of image reconstruction by performing part of image reconstruction calculation in parallel with measurement of magnetic resonance signals, which particularly performs image reconstruction calculation up to (N-1) dimensions of N-dimensional image reconstruction calculation in parallel with measurement of signals and performs the image reconstruction calculation for the remaining one-dimensional direction after the measurement has been finished. When calculation for the last one dimension is performed, the (N-1)-dimensional images for which image reconstruction has been completed are successively displayed, and the image reconstruction calculation for the remaining one-dimensional direction is carried out not by FFT but by discrete Fourier transform, or such that the order of signal measurement is made in the bit reversed order for the order of phase encoding quantity, and thereby, a further portion of the image reconstruction calculation is carried out in parallel with the signal measurement.

摘要翻译： 一种用于MRI成像的方法和装置，其能够通过与磁共振信号的测量并行地执行图像重建计算的一部分来减少测量结束和完成图像重建之间的时间，其特别地执行直到（N-1）的图像重建计算， 与维度信号并行地进行N维图像重建计算的尺寸，并且在测量完成之后对剩余的一维方向执行图像重建计算。 当执行最后一个维度的计算时，连续地显示已经完成图像重建的（N-1）维图像，并且不通过FFT进行剩余一维方向的图像重建计算，而是通过 离散傅里叶变换，或者相位编码量的顺序，以比特相反的顺序进行信号测量的顺序，从而与信号测量并行地进行图像重构计算的另一部分。

公开(公告)号：US4914727A

公开(公告)日：1990-04-03

申请号：US313439

申请日：1989-02-22

申请人： Koichi Sano ,  Akira Maeda ,  Tetsuo Yokoyama ,  Shigenobu Yanaka ,  Hideaki Koizumi

发明人： Koichi Sano ,  Akira Maeda ,  Tetsuo Yokoyama ,  Shigenobu Yanaka ,  Hideaki Koizumi

IPC分类号： G01R33/44 ,  A61B5/055 ,  A61B10/00 ,  G01R33/48 ,  G01R33/561

CPC分类号： G01R33/561 ,  G01R33/5617 ,  G01R33/5619

摘要： A method of MR dynamic imaging comprises the steps of uniformly dividing one scan which is a minimum measurement unit in generating one image data into a plurality of cycles, sequentially extracting one-scan data which are staggered by a predetermined number of cycles, from a series of data derived by repeating the scan a plurality of times in such a manner that the measurement data in each cycle includes high frequency component and low frequency component of the image, and generating image data from the extracted data.

摘要翻译： MR动态成像的方法包括以下步骤：将作为最小测量单位的一个扫描均匀地划分为将多个循环中的一个图像数据生成一个图像数据，从一系列的顺序提取以预定数量的周期交错的一个扫描数据 通过多次重复扫描得到的数据，使得每个周期中的测量数据包括图像的高频分量和低频分量，并且从提取的数据生成图像数据。

公开(公告)号：US4875012A

公开(公告)日：1989-10-17

申请号：US153199

申请日：1988-02-08

申请人： Akira Maeda ,  Koichi Sano ,  Tetsuo Yokoyama ,  Hideaki Koizumi ,  Hirotaka Mizuno

发明人： Akira Maeda ,  Koichi Sano ,  Tetsuo Yokoyama ,  Hideaki Koizumi ,  Hirotaka Mizuno

IPC分类号： F02B3/06 ,  G01R33/56 ,  G01R33/565 ,  G01R33/20

CPC分类号： G01R33/56 ,  G01R33/56527 ,  G01R33/56563 ,  F02B3/06

摘要： In an nuclear magnetic resonance imaging system for acquiring a tomographic image of an object of interest at a high speed by use of time-varying gradient magnetic fields, a weighting factor is used in reconstructing an image through the calculation of a correlation of data of a detected nuclear magnetic resonance signal with data of a reference signal, thereby controlling the point spread function and/or the signal-to-noise ratio in each point on the reconstruction image. Also, the effect of relaxation, chemical shift and/or static magnetic field inhomegeneity, which would otherwise degradate the image quality, can be corrected. Further, a velocity of the object of interest at each point on the reconstruction image can be measured.

摘要翻译： 在用于通过使用时变梯度磁场以高速获取感兴趣对象的断层图像的核磁共振成像系统中，通过计算图像的数据的相关性来使用加权因子来重建图像 检测到具有参考信号的数据的核磁共振信号，从而控制重建图像中每个点上的点扩散函数和/或信噪比。 此外，可以校正松弛，化学位移和/或静态磁场不均匀性的效果，否则会降低图像质量。 此外，可以测量重建图像上的每个点处的感兴趣对象的速度。

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。

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。

公开(公告)号：US4870362A

公开(公告)日：1989-09-26

申请号：US133069

申请日：1987-12-15

申请人： Koichi Sano ,  Shimbu Yamagata ,  Tetsuo Yokoyama ,  Hideaki Koizumi

发明人： Koichi Sano ,  Shimbu Yamagata ,  Tetsuo Yokoyama ,  Hideaki Koizumi

IPC分类号： G01P13/00 ,  A61B5/0265 ,  A61B5/055 ,  A61B10/00 ,  G01R33/44 ,  G01R33/48 ,  G01R33/563 ,  G01R33/567 ,  G06T1/00

CPC分类号： G01R33/565 ,  G01R33/56316 ,  G01R33/56563 ,  G01R33/5659

摘要： To display the information, as an image, regarding the moving portion of the object without the aid of the doctor, the image is reconstructed on the basis of the observed NMR signal and the image phase information is calculated from the image intensity information derived from the reconstructed image, and the phase information calculated is displayed as the image.

摘要翻译： 为了在没有医生帮助的情况下作为图像显示关于物体的移动部分的信息，基于观察到的NMR信号重建图像，并且根据从图像强度信息导出的图像强度信息来计算图像相位信息 重建图像，并且计算的相位信息被显示为图像。