公开(公告)号：US4812760A

公开(公告)日：1989-03-14

申请号：US78427

申请日：1987-07-27

申请人： Paul A. Bottomley ,  Christopher J. Hardy ,  Matthew O'Donnell ,  Peter B. Roemer

发明人： Paul A. Bottomley ,  Christopher J. Hardy ,  Matthew O'Donnell ,  Peter B. Roemer

IPC分类号： A61B10/00 ,  A61B5/055 ,  G01R33/48 ,  G01R33/20

CPC分类号： G01R33/446

摘要： A single rotating NMR .pi. pulse provides simultaneous spatially-selective inversion or spin-echo refocussing of nuclear pins in two orthogonal dimensions. The two-dimensional spatially-selective pulse utilizes a single RF pulse, with either a square of an amplitude-modulated or a frequency-modulated envelope, and applied in the presence of an amplitude-modulated magnetic field gradient which reorients through the desired dimensions in which selection is desired while the RF pulse is present. These rotating, or ".rho.", pulses are useful for reduction of aliasing signal artifacts is restricted field-of-view high-resolution NMR imaging and, when combined with one-dimensional-localized chemical shift spectroscpoy techniques (such as those employing surface detection coils) is especially useful for the production of three-dimensionally localized NMR spectra. Substantial suppression of undesirable residual excited signals, arising from outside the desired two-dimensional spatially selected region, can be obtained by simulated annealing optimization of both the RF and magnetic field gradient amplitude portions of the .rho. pulse and/or by use of surface coil detection. The location of the selected volume is varied by frequency modulation of the RF signal pulse, or by variation of the ratio of currents in the halves of the magnetic field gradient coils.

公开(公告)号：US4885539A

公开(公告)日：1989-12-05

申请号：US202624

申请日：1988-06-06

申请人： Peter B. Roemer ,  Paul A. Bottomley ,  William A. Edelstein

发明人： Peter B. Roemer ,  Paul A. Bottomley ,  William A. Edelstein

IPC分类号： A61B5/055 ,  G01R33/34 ,  H01F7/20

CPC分类号： G01R33/34046

摘要： A RF volume coil with optimized signal-to-noise ratio, for NMR use, has a reduced length L.sub.c, which is between about 0.3r.sub.s and about 1.5r.sub.s, where r.sub.s is the radius of a sample-to-be-investigated, contained within the cylindrical volume coil, with the volume coil radius r.sub.c being between about 1.0r.sub.s and about 1.6r.sub.s. the "short" volume coil has an improved SNR for a voxel located substantially on the central plane of the coil, relative to the SNR of a "normal"-lenth volume coil with L.sub.c .gtoreq.4r.sub.s.

公开(公告)号：US4881032A

公开(公告)日：1989-11-14

申请号：US260633

申请日：1988-10-21

申请人： Paul A. Bottomley ,  Peter B. Roemer ,  William A. Edelstein ,  Otward M. Mueller

发明人： Paul A. Bottomley ,  Peter B. Roemer ,  William A. Edelstein ,  Otward M. Mueller

IPC分类号： A61B5/055 ,  G01R33/36 ,  G01R33/48 ,  G01R33/485

CPC分类号： G01R33/485 ,  G01R33/3628

摘要： A method for NMR spectroscopy metabolite imaging utilizes the steps of: applying to a desired portion of a sample a pulsed phase-encoding linear magnetic gradient signal in at least one of the three orthogonal dimensions of a Cartesian coordinate set, prior to acquisition of free-induction-decay NMR response signals from the sample portion; substantially eliminating from at least the sample portion eddy current fields induced responsive to the phase-encoding gradient pulses; maximizing the signal-to-noise ratio of the NMR response signals; and displaying the data resulting from Fourier transformation of the received response data. A high-field NMR imaging system is provided with self-shielded gradient coils, to subsantially remove eddy-current effects, and at least one of maximized-SNR antenna, of quadrature-driven volume RF coil and/or surface RF coil types are utilized for both transmission of the excitation RF pulses and reception of the RF response signals. The acquired FID data is filtered and a Fourier transform reconstruction, of dimension d' equal to one greater than the numder d of spatial dimensions to be displayed, is performed.

公开(公告)号：US5365927A

公开(公告)日：1994-11-22

申请号：US146345

申请日：1993-11-02

申请人： Peter B. Roemer ,  Samuel M. Blumenfeld ,  Kirby G. Vosburgh ,  Harvey E. Cline ,  William D. Barber ,  William E. Lorensen ,  Richard L. St. Peters ,  John F. Schenck ,  Charles L. Dumoulin ,  Robert D. Darrow ,  Christopher J. Hardy

发明人： Peter B. Roemer ,  Samuel M. Blumenfeld ,  Kirby G. Vosburgh ,  Harvey E. Cline ,  William D. Barber ,  William E. Lorensen ,  Richard L. St. Peters ,  John F. Schenck ,  Charles L. Dumoulin ,  Robert D. Darrow ,  Christopher J. Hardy

IPC分类号： G01R33/48 ,  A61B5/055 ,  G01R33/28 ,  G01R33/38 ,  G01R33/385 ,  G01R33/54 ,  G01R33/563

CPC分类号： G01R33/385 ,  G01R33/3806 ,  G01R33/285 ,  G01R33/4804 ,  G01R33/543 ,  G01R33/563

摘要： A magnetic resonance (MR) imaging system for use in a medical procedure employs an open main magnet allowing access to a portion of a patient within an imaging volume, for producing a main magnetic field over the imaging volume; a set of open gradient coils which provide magnetic fields gradients over the imaging volume without restricting access to the imaging volume; a radiofrequency coil set for transmitting RF energy into the imaging volume to nutate nuclear spins within the imaging volume and receive an MR response signal from the nuclear spins; and a pointing device for indicating the position and orientation of a plane in which an image is to be acquired; an image control means for operating power supplies for the gradient coils and the RF coils to acquire an MR signal from the desired imaging plane; and a computation unit for constructing an image of the desired imaging plane. The MR imaging system is intended to operate to provide images to a physician during medical procedures to guide the physician in his procedures.

摘要翻译： 用于医疗过程的磁共振（MR）成像系统采用打开的主磁体，其允许进入成像体积内的患者的一部分，用于在成像体积上产生主磁场; 一组开放的梯度线圈，其在成像体积上提供磁场梯度，而不限制对成像体积的访问; 射频线圈组，用于将RF能量传输到成像体积中，以在成像体积内盘旋核自旋，并从核自旋接收MR响应信号; 以及指示装置，用于指示要获取图像的平面的位置和方位; 图像控制装置，用于操作梯度线圈和RF线圈的电源，以从期望的成像平面获取MR信号; 以及用于构造所需成像平面的图像的计算单元。 MR成像系统旨在在医疗程序期间向医生提供图像以在他的程序中指导医师。

公开(公告)号：US5027071A

公开(公告)日：1991-06-25

申请号：US489124

申请日：1990-03-05

申请人： Christopher J. Hardy ,  Peter B. Roemer ,  Otward M. Mueller

发明人： Christopher J. Hardy ,  Peter B. Roemer ,  Otward M. Mueller

IPC分类号： A61B5/055 ,  G01R33/32 ,  G01R33/36 ,  G01R33/385 ,  G01R33/387 ,  G01R33/54 ,  G01R33/565 ,  G06T1/00

CPC分类号： G01R33/385 ,  G01R33/56518 ,  G01R33/3607 ,  G01R33/3852

摘要： A method of reducing slice profile degradation due to gradient signal amplitude ripple, has steps of: sensing the gradient signal ripple amplitude; normalizing the sensed ripple signal amplitude responsive to the gradient amplitude commanded; and modulating the RF signal amplitude with the adjusted-amplitude ripple signal, to cause the RF and gradient magnetic fields to have an effective vector pointing substantially in the same direction, during the slice-selection interval, as would the effective field vector formed with a gradient field devoid of ripple. Apparatus for reducing the slice profile degradation modulates the RF signal with the ripple envelope obtained from the output of the gradient signal amplifier, by a signal controlled by the gradient amplifier input.

公开(公告)号：US5179338A

公开(公告)日：1993-01-12

申请号：US759337

申请日：1991-09-13

申请人： Evangelos T. Laskaris ,  Peter B. Roemer ,  Bizhan Dorri ,  Mark E. Vermilyea

发明人： Evangelos T. Laskaris ,  Peter B. Roemer ,  Bizhan Dorri ,  Mark E. Vermilyea

IPC分类号： G01R33/3815 ,  G01R33/385 ,  G01R33/3873 ,  G01R33/422

CPC分类号： G01R33/385 ,  G01R33/3815 ,  G01R33/3873 ,  G01R33/422

摘要： The invention relates to refrigerated superconducting MR magnets having integrated gradient coils. In particular, the amount of eddy currents produced by the magnet are substantially reduced while reducing the size and weight, and, therefore, the cost of the superconducting magnet required to produce an MR image.

摘要翻译： 本发明涉及具有积分梯度线圈的冷冻超导MR磁体。 特别地，磁体产生的涡流的量大大减小，同时减小了产生MR图像所需的超导磁体的尺寸和重量，并因此降低了超导磁体的成本。

公开(公告)号：US5017871A

公开(公告)日：1991-05-21

申请号：US407180

申请日：1989-09-14

申请人： Otward M. Mueller ,  Peter B. Roemer ,  William A. Edelstein

发明人： Otward M. Mueller ,  Peter B. Roemer ,  William A. Edelstein

IPC分类号： G01R33/20 ,  A61B5/055 ,  G01R33/385

CPC分类号： G01R33/3852

摘要： A gradient current speed-up circuit, for use in a higher-speed NMR imaging system with a gradient power amplifier and an associated gradient, coil, has a high-voltage power supply which is selectively connected to the associated gradient coil, typical via a plurality of semiconductor switching elements, to supply a pulse of a very high voltage when fast coil rise and fall times are needed. The gradient coil is connected between selected ones of semiconductors devices which are turned on and off in selected patterns, to cause the direction of coil current flow to be determined.

公开(公告)号：US4614930A

公开(公告)日：1986-09-30

申请号：US715709

申请日：1985-03-25

申请人： John S. Hickey ,  Peter B. Roemer

发明人： John S. Hickey ,  Peter B. Roemer

IPC分类号： G01R33/383 ,  A61B5/055 ,  A61B10/00 ,  G01R33/20 ,  H01F7/02

CPC分类号： H01F7/0278

摘要： A permanent magnet assembly for use in magnetic resonance imagers requires a minimum of permanent magnet material. The magnets are arranged with a radial direction of magnetization and an iron return path is used. The specific configurations of the permanent magnets provide highly uniform magnetic fields in the bore of the assembly.

摘要翻译： 用于磁共振成像器的永磁体组件需要最少的永久磁铁材料。 磁体被布置成具有径向磁化方向，并且使用铁返回路径。 永磁体的具体构造在组件的孔中提供高度均匀的磁场。

公开(公告)号：US5804969A

公开(公告)日：1998-09-08

申请号：US847431

申请日：1997-04-24

申请人： Jianyu Lian ,  Peter B. Roemer

发明人： Jianyu Lian ,  Peter B. Roemer

IPC分类号： G01R33/3415 ,  G01R33/32

CPC分类号： G01R33/3415

摘要： An MRI RF coil has two resonant rings disposed along an axis. The resonant rings are inductively coupled, but are otherwise electrically isolated from one another. In an assembly having two such MRI RF coils, a decoupling element (e.g., a decoupling capacitor or inductor) electrically connected between one ring of one coil and one ring of the other coil decouples the coils.

摘要翻译： MRI RF线圈具有沿轴线设置的两个谐振环。 谐振环感应耦合，但彼此电隔离。 在具有两个这样的MRI RF线圈的组件中，电连接在一个线圈的一个环和另一个线圈的一个环之间的去耦元件（例如，去耦电容器或电感器）使线圈解耦。

公开(公告)号：US5270657A

公开(公告)日：1993-12-14

申请号：US965131

申请日：1992-10-22

申请人： William F. Wirth ,  Thomas G. McFarland ,  Robert M. Vavrek ,  Peter B. Roemer ,  Otward M. Mueller ,  John N. Park

发明人： William F. Wirth ,  Thomas G. McFarland ,  Robert M. Vavrek ,  Peter B. Roemer ,  Otward M. Mueller ,  John N. Park

IPC分类号： G01R33/385 ,  G01V3/00

CPC分类号： G01R33/3852

摘要： A gradient amplifier for use in magnetic resonance imaging equipment employs a low voltage DC power supply connected in series between a pair of higher voltage DC power supplies, the latter supplies serving to provide increased power for rapid gradient switching and the former supply providing correction current to produce the desired voltage output. The high voltage DC power supplies preferably comprise multiple DC units which can be combined to provide finer steps of control prior to correction by the lower voltage supply. The low voltage DC power supply preferably comprise one or more linear amplifiers connected in series, or one or more switchmode amplifiers connected in series. The DC power supplies are controlled in an open loop manner from a gradient signal that designates the desired current for the gradient coil and the amplifiers are operated in a closed loop responding to to a feedback signal from the gradient coil.

摘要翻译： 用于磁共振成像设备的梯度放大器采用串联连接在一对高压直流电源之间的低压直流电源，后者用于为快速梯度切换提供增加的功率，而前一个电源提供校正电流 产生所需的电压输出。 高压DC电源优选地包括多个DC单元，其可以组合以在由较低电压源进行校正之前提供更精细的控制步骤。 低压DC电源优选地包括串联连接的一个或多个线性放大器或串联连接的一个或多个开关模式放大器。 直流电源由开路环路控制，该梯度信号指定用于梯度线圈的期望电流，并且放大器响应于来自梯度线圈的反馈信号在闭环中工作。