公开(公告)号：US5629624A

公开(公告)日：1997-05-13

申请号：US545068

申请日：1990-06-29

申请人： Joseph W. Carlson ,  Lawrence E. Crooks ,  Leon Kaufman

发明人： Joseph W. Carlson ,  Lawrence E. Crooks ,  Leon Kaufman

IPC分类号： A61B5/055 ,  G01R33/38 ,  G01R33/48 ,  G01R33/56 ,  G01R33/561 ,  G01V3/00

CPC分类号： G01R33/445 ,  G01R33/38 ,  G01R33/50 ,  G01R33/56 ,  G01R33/561 ,  G01R33/383

摘要： Switched magnetic fields (in addition to the usual pulsed magnetic gradient fields) aiding and/or opposing the usual constant static magnetic field B.sub.o are utilized so as to increase the signal-to-noise ratio for given available imaging sequence times and/or to provide special imaging effects.

摘要翻译： 利用与通常的恒定静磁场Bo相辅相和/或相反的开关磁场（除了通常的脉冲磁梯度场），以增加给定的可用成像序列时间的信噪比和/或提供 特殊成像效果。

公开(公告)号：US4820988A

公开(公告)日：1989-04-11

申请号：US105738

申请日：1987-10-07

申请人： Lawrence E. Crooks ,  Joseph W. Carlson

发明人： Lawrence E. Crooks ,  Joseph W. Carlson

IPC分类号： G01R33/20 ,  A61B5/055 ,  G01R33/38 ,  G01R33/385

CPC分类号： G01R33/385

摘要： In a gradient coil set for a magnetic resonance system, the y gradient coils are located substantially closer to the patient than are the x and z gradient coils. As a result, one may design the y gradient coils to produce a stronger y gradient, to have reduced inductance or otherwise better tailor the magnetic/electrical properties of the gradient coil set for MRI imaging sequences. In the exemplary embodiment, at least portions of the y gradient coils have a first spacing from the z-axis while the x and z gradient coils have a second substantially larger spacing from the z-axis. Furthermore, while the x and z gradient coils are centered about the z-axis in the patient access space, alternate sides of the y gradient coil set are centered about respectively off-set centers vertically displaced from the z-axis center of the patient access area. The result is a substantially rectangular or elliptical patient access opening with horizontal dimensions defined by the x, z coils sets and vertical dimensions defined by the y coil set.

公开(公告)号：US4970457A

公开(公告)日：1990-11-13

申请号：US363187

申请日：1989-06-08

申请人： Leon Kaufman ,  Lawrence E. Crooks ,  James D. Hale ,  David M. Kramer ,  Kristen Hake ,  Heckor Avram ,  Joel Wummer

发明人： Leon Kaufman ,  Lawrence E. Crooks ,  James D. Hale ,  David M. Kramer ,  Kristen Hake ,  Heckor Avram ,  Joel Wummer

IPC分类号： A61B5/055 ,  G01R33/48 ,  G01R33/565 ,  G01R33/58

CPC分类号： G01R33/583 ,  G01R33/56563

摘要： Static B.sub.o field strength is measured during each TR interval of an MRI sequence providing field calibration data used to compensate for rapid variations in B.sub.o during the MRI sequence.

公开(公告)号：US4885542A

公开(公告)日：1989-12-05

申请号：US181440

申请日：1988-04-14

申请人： Ching Yao ,  James D. Hale ,  Lawrence E. Crooks ,  Leon Kaufman

发明人： Ching Yao ,  James D. Hale ,  Lawrence E. Crooks ,  Leon Kaufman

IPC分类号： A61B5/055 ,  G01R33/48 ,  G01R33/565 ,  G01R33/58

CPC分类号： G01R33/56563 ,  G01R33/56518 ,  G01R33/583

摘要： At least one extra NMR measurement cycle is performed without any imposed magnetic gradients during readout and recordation of the NMR RF response. Calibration data derived from this extra measurement cycle or cycles can be used for resetting the RF transmitter frequency and/or for phase shifting other conventionally acquired NMR RF response data to compensate for spurious changes in magnetic fields experienced during the NMR data measuring processes. Some such spurious fields may be due to drifting of the nominally static magnetic field. Another source of spurious fields are due to remnant eddy currents induced in surrounding conductive structures by magnetic gradient pulses employed prior to the occurrence of the NMR RF response signal. Special procedures can be employed to permit the compensation data itself to be substantially unaffected by relatively static inhomogeneities in the magnetic field and/or by differences in NMR spectra of fat and water types of nuclei in imaged volumes containing both.

公开(公告)号：US4721912A

公开(公告)日：1988-01-26

申请号：US781735

申请日：1985-09-30

申请人： Leon Kaufman ,  Lawrence E. Crooks ,  Douglas A. Ortendahl

发明人： Leon Kaufman ,  Lawrence E. Crooks ,  Douglas A. Ortendahl

IPC分类号： A61B10/00 ,  A61B5/055 ,  G01R33/48 ,  G01R33/54 ,  G01R33/56 ,  G01R33/561 ,  G01R33/567 ,  G01R33/20

CPC分类号： G01R33/482 ,  G01R33/561 ,  G01R33/4824 ,  G01R33/56509

摘要： NMR imaging apparatus and method is arranged so as elicit NMR image response data in a predetermined order which provides the more significant lower spatial frequency image data during an initial portion of a relatively long complete image data acquisition cycle. The remaining higher spatial frequency image data is captured during subsequent portions of the overall image data acquisition cycle. In this manner, apparent motion artifact in the resulting image is reduced. Furthermore, such a special data acquisition sequence permits image reconstruction processes to produce a recognizable image at an earlier time in the complete data gathering cycle thus permitting a more timely image display for the apparatus operator to use in monitoring and/or controlling the NMR imaging procedure.

摘要翻译： NMR成像装置和方法被布置成以预定顺序引出NMR图像响应数据，其在较长的完整图像数据采集周期的初始部分期间提供更显着的较低空间频率图像数据。 在整个图像数据采集周期的后续部分中捕获剩余的较高空间频率图像数据。 以这种方式，所得图像中的视觉运动伪影减小。 此外，这样的特殊数据采集序列允许图像重建过程在完整的数据收集周期中在较早的时间产生可识别的图像，从而允许装置操作者更及时的图像显示用于监测和/或控制NMR成像过程 。

公开(公告)号：US4783629A

公开(公告)日：1988-11-08

申请号：US105737

申请日：1987-10-07

申请人： Mitsuaki Arakawa ,  Lawrence E. Crooks

发明人： Mitsuaki Arakawa ,  Lawrence E. Crooks

IPC分类号： G01R33/36 ,  G01R33/20

CPC分类号： G01R33/3628 ,  G01R33/34069

摘要： An RF coil for a magnetic resonance imaging device using nuclear magnetic resonance phenomena includes self-tracking ganged coupling capacitors which provide impedance matching and also tune out coil inductance to establish resonance at the RF operating frequency. At least one variable capacitor connected in parallel with the RF coil is mechanically ganged to at least one variable capacitor connected in series to the RF coil. The parallel and series capacitances are initially set to achieve resonance at a desired operating frequency. As the shaft of one variable capacitor is rotated in a first direction through a given angle, the shaft of the other variable capacitor rotates in the opposite direction through the same angle, thereby varying the ratio (but not the sum) of parallel and series capacitances. A servo controller connected to a standing wave ratio detector automatically adjusts the ratio of parallel to series capacitances to optimize impedance matching between the source and the RF coil.

摘要翻译： 用于使用核磁共振现象的磁共振成像装置的RF线圈包括提供阻抗匹配的自跟踪组合耦合电容器，并且还调出线圈电感以在RF操作频率处建立谐振。 与RF线圈并联连接的至少一个可变电容器被机械地组合到与RF线圈串联连接的至少一个可变电容器。 初始设置并联和串联电容以在期望的工作频率下实现谐振。 当一个可变电容器的轴沿第一方向旋转一定角度时，另一个可变电容器的轴沿相反的方向旋转相同的角度，从而改变并联和串联电容的比值（而不是总和） 。 连接到驻波比检测器的伺服控制器自动调节并联到串联电容的比率，以优化源极和RF线圈之间的阻抗匹配。

公开(公告)号：US4763076A

公开(公告)日：1988-08-09

申请号：US93670

申请日：1987-09-08

申请人： Mitsuaki Arakawa ,  Lawrence E. Crooks

发明人： Mitsuaki Arakawa ,  Lawrence E. Crooks

IPC分类号： G01R33/36 ,  G01R33/20

CPC分类号： G01R33/3657 ,  G01R33/3628

摘要： A detuning/decoupling arrangement for a Magnetic Resonance Imaging (MRI) system RF coil arrangement (of the typing using the nuclear magnetic resonance, or NMR, phenomenon) uses switching diodes to selectively connect and disconnect portions of an RF resonant circuit in response to a DC control signal. The DC control signal selectively forward biases and reverse biases the switching diodes. The DC control current is fed to the resonant circuit along the same RF transmission line used to feed RF signals to/from the circuit. An in-line coaxial shielded RF choke connected to the RF transmission line isolates the DC control signals from the RF signals flowing on the same transmission line--reducing the number and complexity of isolation devices required on the ends of the transmission line to separate the RF and DC signals.

摘要翻译： 用于磁共振成像（MRI）系统的解耦/去耦排列（使用核磁共振或NMR的现象进行分类）的RF线圈装置使用开关二极管来选择性地连接和断开RF谐振电路的部分，以响应于 直流控制信号。 DC控制信号选择性地向前偏置和反向偏置开关二极管。 直流控制电流沿着用于将RF信号馈送到电路的相同RF传输线馈送到谐振电路。 连接到RF传输线的同轴同轴屏蔽RF扼流器将DC控制信号与在相同传输线上流动的RF信号隔离开来 - 减少了传输线端部所需的隔离设备的数量和复杂性，从而将RF 和直流信号。

公开(公告)号：US5606258A

公开(公告)日：1997-02-25

申请号：US032647

申请日：1993-03-17

申请人： John C. Hoenninger, III ,  Lawrence E. Crooks

发明人： John C. Hoenninger, III ,  Lawrence E. Crooks

IPC分类号： G01R33/54 ,  G06F19/00 ,  G01V3/00

CPC分类号： G01R33/54 ,  G06F19/3406 ,  G01R33/543

摘要： A control interface for a magnetic resonance imaging (MRI) system provides extended, improved linker syntax/techniques that maximize reuse of program segments, allow optimal compromise between detailed representation and efficient sequence program design and maintenance, and permit uniform application of the loop syntax to link commands for MRI sequencers with a wide range of hardware implementations. The control interface provides, among other features, generalized loops at the link level; loop symbols representing loop identity can be associated with scope and/or range (with some kind of limited grammar in the link command itself that supports identification of scope and/or range); parameter tables that can be associated with loop symbols (any given table can be associated with N loop symbols in order to provide multidimensional sequences); multiple levels of loop nesting; and directed limited syntax that provides limited grammar, and range and syntax checking and requires the user to explicitly enter information into the interface.

摘要翻译： 用于磁共振成像（MRI）系统的控制界面提供扩展的改进的链接器语法/技术，其最大程度地重用程序段，允许在详细表示和有效的顺序程序设计和维护之间的最佳折中，并允许循环语法的均匀应用 用于具有广泛硬件实现的MRI定序器的链接命令。 除了其他特征之外，控制接口还提供了链路级的通用循环; 表示循环标识的循环符号可以与范围和/或范围相关联（在链接命令本身中具有支持范围和/或范围的识别的某种有限的语法）; 可以与循环符号相关联的参数表（任何给定的表可以与N个循环符号相关联，以便提供多维序列）; 多级循环嵌套; 并提供有限的语法，提供有限的语法，范围和语法检查，并要求用户明确地将信息输入到界面中。

公开(公告)号：US5529068A

公开(公告)日：1996-06-25

申请号：US260789

申请日：1994-06-16

申请人： John C. Hoenninger, III ,  Lawrence E. Crooks ,  James W. Jones

发明人： John C. Hoenninger, III ,  Lawrence E. Crooks ,  James W. Jones

IPC分类号： G01R33/36 ,  A61B5/055

CPC分类号： G01R33/3621

摘要： A multi-rate sample MRI (magnetic resonance imaging) digital receiver maintains synchronization of digitally processed signals. This multi-rate sample data system is used to demodulate and filter a digitized MRI RF signal. A phase/timing relationship is established between the signal received and processed by the digital receiver, and the physical nuclear magnetic resonance (NMR) process the body being imaged is undergoing. Once established, the phase/timing relationship is maintained for the duration of the particular NMR experiment being performed. Special logic in the digital system ensures that the data output is synchronized with an external synchronous signal controlling data acquisition within the MRI system. Optimum signal processing is performed to minimize the time between the end of the acquisition control signal and the last output from the digital signal processing system.

摘要翻译： 多速率采样MRI（磁共振成像）数字接收机保持数字处理信号的同步。 该多速率采样数据系统用于对数字化的MRI RF信号进行解调和滤波。 在由数字接收机接收和处理的信号之间建立相位/定时关系，并且正在成像的身体正在进行物理核磁共振（NMR）处理。 一旦建立，在执行特定NMR实验的持续时间内，维持相位/时间关系。 数字系统中的特殊逻辑确保数据输出与控制MRI系统内数据采集的外部同步信号同步。 执行最佳信号处理以最小化采集控制信号的结束与来自数字信号处理系统的最后输出之间的时间。

公开(公告)号：US5442290A

公开(公告)日：1995-08-15

申请号：US924508

申请日：1992-08-04

申请人： Lawrence E. Crooks

发明人： Lawrence E. Crooks

IPC分类号： A61B5/055 ,  G01R33/385 ,  G01R33/48 ,  G05F7/00

CPC分类号： G01R33/3852 ,  G05F7/00

摘要： An all digital controlled current driver is used for each pulsed electromagnet (e.g., gradient coils) in a magnetic resonance imaging (MRI) system. Such an all digital current controller may be advantageously employed in either closed loop or open loop gradient coil control circuits. The elimination of analog components decreases cost, increases operating efficiency and improves operating characteristics of the MRI system.

摘要翻译： 在磁共振成像（MRI）系统中，所有数字控制电流驱动器用于每个脉冲电磁体（例如梯度线圈）。 这种全数字电流控制器可以有利地用于闭环或开环梯度线圈控制电路中。 模拟部件的消除降低了成本，提高了运行效率，提高了MRI系统的运行特性。