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    Low eddy current radio frequency shield for magnetic resonance imaging
    4.
    发明授权
    Low eddy current radio frequency shield for magnetic resonance imaging 失效
    用于磁共振成像的低涡流射频屏蔽

    公开(公告)号：US5592087A

    公开(公告)日：1997-01-07

    申请号：US379979

    申请日：1995-01-27

    Applicant: Mark A. Richard ,  Xueming Zou ,  Michael A. Morich

    Inventor： Mark A. Richard ,  Xueming Zou ,  Michael A. Morich

    IPC: G01R33/421 ,  A61B5/055 ,  G01R33/38 ,  G01R33/422 ,  G01H3/00 ,  G01H3/14

    CPC classification number: G01R33/422 ,  G01R33/4215

    Abstract: A magnetic resonance imaging apparatus includes a magnet assembly (10) for generating a temporally constant primary magnetic field through a central bore (14). The central bore is surrounded by a gradient coil assembly (30) including a dielectric former (32) and gradient coils (34, 36, 38) for generating magnetic field gradient pulses across the examination region. A radio frequency coil assembly (50) including a birdcage coil (52) is mounted inside of the gradient coil assembly and surrounding the examination region. A radio frequency shield (60) includes a dielectric sheet (62) having a plurality of first metal foil strips (72) defined on each surface. The metal strips are defined by etching or cutting gaps (70) in a continuous sheet of copper foil, leaving bridges (74) across the gaps adjacent opposite ends of the foil strips. The foil strips on opposite faces of the dielectric sheet are offset by half the width of one strip such that each strip is capacitively coupled to two strips on the opposite surface. The radio frequency coil induces radio or megahertz frequency eddy currents to which the capacitive coupling appears as a short-circuit, allowing the induced radio frequency currents to pass circumferentially around the shield. The gradient coil assembly induces kilohertz frequency eddy currents to which the capacitive couplings appear as open circuits. The kilohertz eddy currents flow longitudinally along a strip, cross a bridge adjacent one end of the strip, and flow back longitudinally along an adjacent strip, and so forth.

    Abstract translation: 磁共振成像装置包括用于通过中心孔（14）产生时间上恒定的初级磁场的磁体组件（10）。 中心孔被包括电介质成形器（32）和梯度线圈（34,36,38）的梯度线圈组件（30）包围，用于在整个检查区域上产生磁场梯度脉冲。 包括鸟笼线圈（52）的射频线圈组件（50）安装在梯度线圈组件的内部并且围绕检查区域。 射频屏蔽（60）包括具有限定在每个表面上的多个第一金属箔条（72）的电介质片（62）。 通过在连续的铜箔片中蚀刻或切割间隙（70）来限定金属条，留下邻近箔片条相对端的间隙的桥（74）。 在电介质片的相对面上的箔片偏移一个条带的宽度的一半，使得每个条带电容耦合到相对表面上的两个条带。 射频线圈引起无线电或兆赫兹频率涡流，其中电容耦合出现为短路，允许感应射频电流围绕屏蔽周向通过。 梯度线圈组件引起千伏频率涡流，电容耦合作为开路出现。 千赫兹涡流沿着条带纵向流动，穿过邻近条带一端的桥，并且沿着相邻条带纵向流回，等等。

    Magnetic resonance imager with removable element RF coil
    5.
    发明授权
    Magnetic resonance imager with removable element RF coil 失效
    具有可拆卸元件射频线圈的磁共振成像仪

    公开(公告)号：US5457387A

    公开(公告)日：1995-10-10

    申请号：US87929

    申请日：1993-07-06

    Applicant: John L. Patrick ,  Xueming Zou ,  Nicholas J. Mastandrea ,  Paul T. Orlando

    Inventor： John L. Patrick ,  Xueming Zou ,  Nicholas J. Mastandrea ,  Paul T. Orlando

    IPC: G01R33/34 ,  G01R33/20

    CPC classification number: G01R33/34007 ,  G01R33/34

    Abstract: A primary gradient coil assembly (22) is mounted in the inner bore or cylinder (20) of a vacuum dewar (18) that surrounds a superconducting magnet assembly (10). A pair of end ring assemblies, such as electrically conductive lapped segment loops (38) are supported by the gradient coil assembly (22). The end ring segments are capacitively coupled. A plurality of removable radio frequency coil element assemblies (40) are selectively attached to and detached from the gradient coil assembly. Each of the removable RF coil element assembly includes a dielectric housing (50), a longitudinally extending conductor element (52), an electrical connector (44), and circuit components (54) which connects the longitudinal conductor element with the electrical connector. The connector is electrically connected, at radio frequencies, with the ring assembly (38). A mechanical interlock (60) mechanically locks and selectively releases the removable element assemblies (40) to the gradient coil assembly. Sets of different removable element assemblies are provided with different effective radii, i.e. different physical displacements of the electrical conductor elements (52) from the gradient coil assembly, different resonance frequencies, i.e. different reactive elements (58), and the like to adapt the different removable element assemblies for different imaging applications. The removable element assemblies may be completely removed when specialty RF coils, such as a head coil, biplanar gradient coil, or surface coil are used.

    Abstract translation: 主梯度线圈组件（22）安装在围绕超导磁体组件（10）的真空杜瓦瓶（18）的内孔或气缸（20）中。 一对端环组件，例如导电重叠的段环（38）由梯度线圈组件（22）支撑。 端环段电容耦合。 多个可移除的射频线圈元件组件（40）选择性地附接到梯度线圈组件上并与其分离。 每个可移除RF线圈元件组件包括电介质壳体（50），纵向延伸的导体元件（52），电连接器（44）以及连接纵向导体元件与电连接器的电路元件（54）。 连接器以无线电频率与环组件（38）电连接。 机械互锁（60）机械地锁定并选择性地将可拆卸元件组件（40）释放到梯度线圈组件。 不同可移除元件组件的组件具有不同的有效半径，即电导体元件（52）与梯度线圈组件的不同物理位移，不同的谐振频率，即不同的反应元件（58）等，以适应不同的可移除元件 可移动元件组件用于不同的成像应用。 当使用特殊RF线圈（例如头部线圈，双平面梯度线圈或表面线圈）时，可移除元件组件可以被完全去除。

    Biplanar RF coil for magnetic resonance imaging systems
    6.
    发明授权
    Biplanar RF coil for magnetic resonance imaging systems 失效
    用于磁共振成像系统的双平面RF线圈

    公开(公告)号：US5280248A

    公开(公告)日：1994-01-18

    申请号：US919215

    申请日：1992-07-24

    Applicant: Xueming Zou ,  John L. Patrick ,  Nicholas J. Mastandrea

    Inventor： Xueming Zou ,  John L. Patrick ,  Nicholas J. Mastandrea

    IPC: G01R33/34 ,  G01R33/385 ,  G01R33/422 ,  G01V3/00

    CPC classification number: G01R33/34061 ,  G01R33/385 ,  G01R33/422

    Abstract: A superconducting magnet (10) generates a uniform, static magnetic field through a central bore (12) along its longitudinal or z-axis. A biplanar gradient coil assembly (44) is inserted into the bore to create gradients across the static magnetic field along orthogonal x, y, and z-axes. A biplanar radio frequency coil assembly (50, 80) is inserted into the bore for transmitting radio frequency signals into a subject and receiving magnetic resonance signals from the subject. The radio frequency coil includes a first biplanar coil assembly (50) for generating RF signals in an x-direction and a second biplanar coil assembly (80) for generating RF signals in a y-direction. The two biplanar coil assemblies each include a plurality of conductors (52, 82) along a first plane and a second plurality of conductors (54, 84) along a parallel second plane. The conductors extend parallel to the z-direction. Capacitors (56, 58, 94) are connected in series with each of the conductors in order to control the current flow such that the current flow in each plane is uniform across the plane. The ends of the electrical conductors are connected together (66, 88) such that the current flows are equal and opposite in the two planes. A radio frequency transmitter (136) transmits RF signals to the quadrature biplanar coil assembly. A digital receiver (140) receives and demodulates radio frequency signals from the quadrature coil assembly. The demodulated signals are reconstructed (144) into an image representation for display on a video monitor (146).

    Abstract translation: 超导磁体（10）沿着其纵向或z轴通过中心孔（12）产生均匀的静态磁场。 将双平面梯度线圈组件（44）插入孔中以沿着正交的x，y和z轴在静态磁场上产生梯度。 将双平面射频线圈组件（50,80）插入到孔中，用于将射频信号传输到被摄体中并接收来自被摄体的磁共振信号。 射频线圈包括用于在x方向上产生RF信号的第一双平面线圈组件（50）和用于在y方向上产生RF信号的第二双平面线圈组件（80）。 两个双平面线圈组件各自包括沿着第一平面的多个导体（52,82）和沿着平行的第二平面的第二多个导体（54,84）。 导体平行于z方向延伸。 电容器（56,58,94）与每个导体串联连接，以便控制电流，使得每个平面中的电流在平面上是均匀的。 电导体的端部连接在一起（66,88），使得电流在两个平面中相等和相反。 射频发射器（136）将RF信号发送到正交双平面线圈组件。 数字接收机（140）接收并解调来自正交线圈组件的射频信号。 解调的信号被重建（144）成为用于在视频监视器（146）上显示的图像表示。

    Surface coil decoupling means for MRI systems
    8.
    发明授权
    Surface coil decoupling means for MRI systems 有权
    用于MRI系统的表面线圈去耦装置

    公开(公告)号：US06927575B2

    公开(公告)日：2005-08-09

    申请号：US10761553

    申请日：2004-01-21

    Applicant: Michael Burl ,  Mark Xueming Zou

    Inventor： Michael Burl ,  Mark Xueming Zou

    IPC: G01R33/3415 ,  G01R33/36 ,  G01V3/00

    CPC classification number: G01R33/365 ,  G01R33/3415

    Abstract: A system and method for decoupling coils in a medical imaging system are provided. The coil system includes a first coil of a medical imaging system, a second coil of the medical imaging system, and a balun device connected to the first and second coils. The balun device is configured to decouple the first and second coils of the medical imaging system.

    Abstract translation: 提供了一种用于在医学成像系统中去耦线圈的系统和方法。 线圈系统包括医疗成像系统的第一线圈，医疗成像系统的第二线圈和连接到第一和第二线圈的平衡 - 不平衡转换器件。 平衡 - 不平衡变压器装置被配置为使医疗成像系统的第一和第二线圈解耦。

    Transmit mode coil detuning for MRI systems
    10.
    发明授权
    Transmit mode coil detuning for MRI systems 有权
    MRI系统的发射模式线圈失谐

    公开(公告)号：US06850067B1

    公开(公告)日：2005-02-01

    申请号：US10440834

    申请日：2003-05-19

    Applicant: Michael Burl ,  Mark Xueming Zou

    Inventor： Michael Burl ,  Mark Xueming Zou

    IPC: G01R33/36 ,  G01V3/00

    CPC classification number: G01R33/3657 ,  G01R33/3628

    Abstract: A detuning circuit for an MRI coil having a series tuning capacitor includes: a detuning inductor and a PIN diode in parallel communication with the tuning capacitor, where the tuning capacitor has a tuning inductor node and a PIN diode node; a first diode and a second diode in parallel communication with the PIN diode, where the first, second and PIN diodes are arranged with the same serial polarity and the first and second diodes have a common node; and a reactance in communication between the common node and the tuning inductor node. The circuit detunes the MRI coil in response to an MRI transmit pulse. A detuning circuit for an MRI coil having a series tuning capacitor includes a detuning inductor; and a detuning switch in parallel combination with a secondary tuning capacitor, the detuning inductor and the parallel combination being in parallel communication with the series tuning capacitor. The secondary tuning capacitor acts to reduce current during detuning of the MRI coil.

    Abstract translation: 具有串联调谐电容器的MRI线圈的失谐电路包括：调谐电感器和与调谐电容并联连接的PIN二极管，其中调谐电容器具有调谐电感器节点和PIN二极管节点; 与PIN二极管并联连接的第一二极管和第二二极管，其中第一，第二和PIN二极管以相同的串行极性布置，并且第一和第二二极管具有公共节点; 以及在公共节点和调谐电感器节点之间的通信中的电抗。 该电路响应于MRI发射脉冲使MRI线圈断线。 具有串联调谐电容器的MRI线圈的失谐电路包括失谐电感器; 以及与二次调谐电容并联组合的失谐开关，所述失谐电感器和所述并联组合与所述串联调谐电容器并联连接。 二次调谐电容器用于在MRI线圈失谐期间减小电流。

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