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322 条记录 (耗时 0.02 秒)

    Network to cancel coupling between channels of quadrature antenna coil assembly in a magnetic resonance imaging system
    51.
    发明授权
    Network to cancel coupling between channels of quadrature antenna coil assembly in a magnetic resonance imaging system 失效
    在磁共振成像系统中消除正交天线线圈组件的通道之间的耦合的网络

    公开(公告)号：US4769605A

    公开(公告)日：1988-09-06

    申请号：US935001

    申请日：1986-11-26

    申请人： Timothy R. Fox

    发明人： Timothy R. Fox

    IPC分类号： G01R33/32 ,  A61B5/055 ,  A61B10/00 ,  G01R33/341 ,  G01R33/36 ,  G01R33/20

    CPC分类号： G01R33/365 ,  G01R33/3628 ,  G01R33/3678

    摘要： In a quadrature antenna coil assembly of a magnetic resonance imaging system, the antenna coil assembly having a first receiver coil and a second receiver coil and having external coupling between the first and second receiver coils, a coupling cancellation network has a first set of terminals connected across the first receiver coil, a second set of terminals connected across the second receiver coil, and circuitry, connected between the first and second terminal sets, for generating additional coupling between the first and second receiver coils in opposite polarity and equal magnitude to the external coupling to cancel the external coupling.

    摘要翻译： 在磁共振成像系统的正交天线线圈组件中，天线线圈组件具有第一接收器线圈和第二接收器线圈，并且在第一和第二接收器线圈之间具有外部耦合，耦合消除网络具有连接的第一组终端 跨越第一接收器线圈，连接在第二接收器线圈上的第二组端子和连接在第一和第二端子组之间的电路，用于在第一和第二接收器线圈之间产生与外部相反的极性和相等大小的附加耦合 耦合以取消外部耦合。

    Non-overlapping qd MRI RF coil
    52.
    发明授权
    Non-overlapping qd MRI RF coil 失效
    不重叠的qd MRI射频线圈

    公开(公告)号：US4740752A

    公开(公告)日：1988-04-26

    申请号：US893889

    申请日：1986-08-06

    申请人： Mitsuaki Arakawa ,  John H. Fehn

    发明人： Mitsuaki Arakawa ,  John H. Fehn

    IPC分类号： G01R33/34 ,  G01R33/341 ,  G01R33/20

    CPC分类号： G01R33/3678 ,  G01R33/34046

    摘要： A quadrature detection magnetic resonance imaging (MRI) RF coil is constructed from non-overlapping axially-extending conductors arrayed about the circumference of a cylinder in four circumferentially spaced-apart groupings. Axially-extending annular gaps in the fingers (e.g, at their mid-points) are bridged across by RF coupling capacitors. The outer ends of the fingers are also coupled by annular conductors having one or more conductive gaps bridged by coupling capacitance. First and second quadrature detection RF input/output ports are coupled to at least one respective finger element in each of two adjacent groups of elements.

    摘要翻译： 正交检测磁共振成像（MRI）RF线圈由在四个周向间隔开的组中围绕圆柱体的圆周排列的不重叠的轴向延伸的导体构成。 手指中的轴向延伸的环形间隙（例如在其中点处）被RF耦合电容器跨接。 指状物的外端还通过具有由耦合电容桥接的一个或多个导电间隙的环形导体耦合。 第一和第二正交检测RF输入/输出端口耦合到两个相邻元件组中的每一个中的至少一个相应的手指元件。

    Magnetic resonance imaging apparatus including two orthogonal r.f. coils
    53.
    发明授权
    Magnetic resonance imaging apparatus including two orthogonal r.f. coils 失效
    磁共振成像装置包括两个正交的r.f. 线圈

    公开(公告)号：US4712069A

    公开(公告)日：1987-12-08

    申请号：US841132

    申请日：1986-03-18

    申请人： Rudolf Kemner ,  Hilco T. Kalmijn

    发明人： Rudolf Kemner ,  Hilco T. Kalmijn

    IPC分类号： G01R33/36 ,  A61B5/055 ,  A61B10/00 ,  G01R33/28 ,  G01R33/341 ,  G01R33/20

    CPC分类号： G01R33/3678

    摘要： In an apparatus for performing magnetic resonance measurements by means of an orthogonal system of excitation detection coils there is provided a switching circuit for powering and reading the coil system which includes a 1/4 .lambda. coaxial conductor as a connection between the two coil assemblies and a 1/4 .lambda. coaxial conductor with a 90.degree. phase delay as a connection between the first 1/4 .lambda. conductor and the second coil assembly and a detection device. By suitable tuning of the relevant circuit components and the coils, preferably based on 50 Ohms, a simple switching circuit with appropriate matching and phase correction is thus achieved. Specifically, the r.f. power source can be connected to the circuit via an n .lambda. conductor. In the open condition during detection, the n .lambda. conductor represents an infinite impedance for the switching circuit.

    摘要翻译： 在用于通过激励检测线圈的正交系统进行磁共振测量的装置中，提供了用于为线圈系统供电和读取的开关电路，该线圈系统包括作为两个线圈组件之间的连接的1/4λ同轴导体和 1/4λ同轴导体，具有90°相位延迟，作为第一1/4λ导体和第二线圈组件之间的连接以及检测装置。 通过适当调谐相关的电路部件和线圈，优选地基于50欧姆，因此实现了具有适当的匹配和相位校正的简单的开关电路。 具体来说，r.f. 电源可以通过nλ导体连接到电路。 在检测期间的开路状态下，nλ导体代表开关电路的无限阻抗。

    Matched guadrature coils for MRI with minimized intercoil coupling
    54.
    发明授权
    Matched guadrature coils for MRI with minimized intercoil coupling 失效
    具有最小的线圈耦合的MRI的匹配的线形线圈

    公开(公告)号：US4695801A

    公开(公告)日：1987-09-22

    申请号：US827609

    申请日：1986-02-10

    申请人： Mitsuaki Arakawa ,  John H. Fehn ,  Lawrence E. Crooks

    发明人： Mitsuaki Arakawa ,  John H. Fehn ,  Lawrence E. Crooks

    IPC分类号： A61B10/00 ,  A61B5/055 ,  G01R33/34 ,  G01R33/341 ,  G01R33/36 ,  H01F7/20 ,  G01R33/20

    CPC分类号： G01R33/365 ,  G01R33/3628 ,  G01R33/3678

    摘要： First and second co-located axially extending RF coils are displaced spatially with respect to one another by 90 degrees so as to produce a pair of RF signals from the enclosed volume which are in phase quadrature. The same coils or one of them may also be utilized for transmitting NMR RF signals into the same volume. The coils have a common open-end through which objects to be imaged may be inserted and a common "closed" end for convenient location of RF coupling and feeding structures. Each of the coils has an RF feedline structure which extends across a diameter of common closed end and the two feedline structures are disposed substantially perpendicular with respect to one another so as to minimize cross coupling. The feedlines are also spatially configured to facilitate mounting of associated tuning and coupling capacitors. A fixed coupling "paddle" provides cancellation coupling between the coils and a movably mounted coupling paddle is arranged to provide variable amounts of cancellation coupling between the orthogonal feedline structures. The phase quadrature RF signals emanating from the pair of coils are preferably amplified before being combined in a 90.degree. RF hybrid circuit.

    摘要翻译： 第一和第二同轴轴向延伸的RF线圈相对于彼此空间位移90度，从而产生来自封闭体积的正对相位的一对RF信号。 相同的线圈或其中的一个也可用于将NMR RF信号传输到相同的体积中。 线圈具有通常的开放端，通过该公共开口端可以插入要成像的物体和一个共同的“闭合”端，以便于RF耦合和馈送结构的便利定位。 每个线圈具有横跨公共封闭端的直径延伸的RF馈线结构，并且两个馈线结构相对于彼此基本垂直地设置，以使交叉耦合最小化。 馈线也是空间配置的，以便于安装相关的调谐和耦合电容器。 固定耦合“桨”提供线圈之间的消除耦合，并且可移动地安装的耦合桨被布置成在正交馈线结构之间提供可变量的抵消耦合。 从一对线圈发出的相位正交RF信号优选在90°RF混合电路组合之前被放大。

    Spectrographic analysis of materials
    55.
    发明授权
    Spectrographic analysis of materials 失效
    材料光谱分析

    公开(公告)号：US3999118A

    公开(公告)日：1976-12-21

    申请号：US553725

    申请日：1975-02-27

    申请人： David Ian Hoult

    发明人： David Ian Hoult

    IPC分类号： A61B5/055 ,  G01N24/08 ,  G01R33/341 ,  G01R33/36 ,  G01R33/46 ,  G01R33/08

    CPC分类号： G01R33/3678 ,  G01R33/3607 ,  G01R33/4625

    摘要： In nuclear magnetic resonance apparatus employing detection channels in phase quadrature an excitation-pulse transmitter includes an arrangement of switches and associated delay lines to enable successive pulses to be produced in phase quadrature and alternate pulses to be produced in phase opposition. The receiver output signals corresponding to the quadrature pulse-pairs may then be processed to cancel the effects of phase error and unequal gain in the detection channels and the signals corresponding to the opposing pulse-pairs may be processed to cancel systematic noise.

    摘要翻译： 在采用相位正交的检测通道的核磁共振装置中，激发脉冲发射器包括开关和相关延迟线的布置，以使相邻正交中产生相继的脉冲并产生相位相反的交替脉冲。 然后可以处理对应于正交脉冲对的接收机输出信号以消除检测通道中的相位误差和不相等增益的影响，并且可以处理与相对的脉冲对相对应的信号以消除系统噪声。

    RF TRANSMIT SYSTEM WITH SELECTABLE DRIVE PORTS FOR MAGNETIC RESONANCE IMAGING APPARATUSES
    56.
    发明申请
    RF TRANSMIT SYSTEM WITH SELECTABLE DRIVE PORTS FOR MAGNETIC RESONANCE IMAGING APPARATUSES 审中-公开

    公开(公告)号：US20190113586A1

    公开(公告)日：2019-04-18

    申请号：US16090282

    申请日：2017-04-04

    申请人： KONINKLIJKE PHILIPS N.V.

    发明人： OLIVER LIPS ,  PETER VERNICKEL

    IPC分类号： G01R33/36 ,  G01R33/34 ,  G01R33/345

    CPC分类号： G01R33/3664 ,  G01R33/34076 ,  G01R33/3453 ,  G01R33/3678

    摘要： A radio frequency transmit system (40) for use in magnetic resonance imaging apparatuses, comprising a radio frequency driver unit (42) including at least a first radio frequency power source (44; 82) and a second radio frequency power source (46; 84), a radio frequency coil arrangement (48) for generating an RF magnetic excitation field B1, and a plurality of switching members (68, 70, 72, 74) electrically connecting the radio frequency power sources (44, 46; 82, 84) to different pairs of drive ports (58, 60, 62, 64) in a first and in at least a second switching status. The first drive port (58) of the first pair of drive ports (58, 60) and the first drive port (62) of the at least second pair of drive ports (62, 64) are arranged spaced by a fixed predetermined angular distance in the azimuthal direction (56) about the center axis (50); and a magnetic resonance imaging system (10) including such radio frequency transmit system (40).