公开(公告)号：US5602479A

公开(公告)日：1997-02-11

申请号：US512388

申请日：1995-08-08

申请人： Ravi Srinivasan ,  Haiying Liu ,  Robert A. Elek

发明人： Ravi Srinivasan ,  Haiying Liu ,  Robert A. Elek

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

CPC分类号： G01R33/34046

摘要： In a magnetic resonance imaging apparatus, a radio frequency coil (40) is disposed closely adjacent the patient's head. The radio frequency coil includes a first annular ring (80, 114) around the patient's head from which a first plurality of legs (82, 116) extend. Opposite legs are interconnected equidistant from the first annular ring to form a virtual ground connection (84, 118). In the embodiment of FIG. 6, a second annular ring (120) is disposed parallel to the first annular ring with a second plurality of legs (122) extending between the first and second annular rings. By adjusting a ratio .rho. of the current flow in the loops defined by the first legs, the first annular ring and virtual ground relative to the current loops defined by the second legs and the first and second annular rings, the linearity of the B.sub.1 field within the head coil is selectively adjustable (FIG. 8).

摘要翻译： 在磁共振成像装置中，射频线圈（40）紧邻患者头部设置。 射频线圈包括围绕患者头部的第一环形环（80,114），第一多个腿部（82,116）从该第一环形环延伸。 相对的腿与第一环形环等距离地形成虚拟接地连接（84,118）。 在图1的实施例中 如图6所示，第二环形圈（120）平行于第一环形环设置有在第一和第二环形环之间延伸的第二多个支柱（122）。 通过调节由第一腿，第一环形圈和虚拟地线相对于由第二腿部和第一和第二环形圈限定的电流回路限定的环路中的电流的比率rho，其中B1场的线性度 磁头线圈可选择性地调节（图8）。

公开(公告)号：US06029082A

公开(公告)日：2000-02-22

申请号：US976857

申请日：1997-11-24

申请人： Ravi Srinivasan ,  Haiying Liu ,  Robert A. Elek

发明人： Ravi Srinivasan ,  Haiying Liu ,  Robert A. Elek

IPC分类号： G01R33/34 ,  A61B5/055

CPC分类号： G01R33/34046 ,  G01R33/34084

摘要： A less-claustrophobic, quadrature, radio-frequency head coil (42) includes first and second broken end rings (90, 92) connected to each other in parallel by a plurality of leg conductors (94). At least two of the leg conductors are interconnected by a third arcuate conductor segment (98) axially displaced from planes of the first and second end rings to provide an opening (44) over a subject's face. The opening reduces patient claustrophobia and permits access to the patient for life-support devices or the practice of interventional medicine. The end rings have a fixed capacitance (C.sub.1, C.sub.2) between each pair of leg conductors. The fixed capacitance C.sub.1 between at least one pair of leg conductors and the fixed capacitance C.sub.2 between at least the pair of leg conductors adjacent the opening, where C.sub.2 >C.sub.1. A two-port feed (66, 68) circumferentially attached to the coil generally opposite the opening matches the individual linear modes. Thus, the radio frequency coil is able to maintain two preferred principal linear modes (A, B) across the open area of the coil.

摘要翻译： 较不幽闭的正交射频头线圈（42）包括通过多个腿导体（94）并联连接的第一和第二断开端环（90,92）。 至少两个腿导体通过从第一和第二端环的平面轴向移位的第三弓形导体段（98）互连，以在对象的表面上提供开口（44）。 开幕式可减少患者幽闭恐惧症，并允许进入患者的生命支持设备或介入医学的实践。 端环在每对腿导体之间具有固定电容（C1，C2）。 在至少一对腿导体之间的固定电容C1和固定电容C2之间至少一对腿导体相邻开口，其中C2> C1。 周向地连接到与开口相对的线圈的两端口馈送（66,68）与各个线性模式匹配。 因此，射频线圈能够在线圈的开放区域上保持两个优选的主线性模式（A，B）。

公开(公告)号：US5680047A

公开(公告)日：1997-10-21

申请号：US514396

申请日：1995-08-11

申请人： Ravi Srinivasan ,  Haiying Liu ,  Robert A. Elek

发明人： Ravi Srinivasan ,  Haiying Liu ,  Robert A. Elek

IPC分类号： G01R33/48 ,  A61B5/055 ,  G01R33/36 ,  G01V3/00

CPC分类号： G01R33/3635

摘要： A magnetic resonance system is used to excite high .gamma. dipoles, such as hydrogen, and lower .gamma. dipoles, such as phosphorous, to resonate concurrently. A multiply-tuned radio frequency coil (40) is disposed around the region of interest. The multiply-tuned radio frequency coil is tuned to the resonance frequency of the high .gamma. dipoles and the resonance frequency of the low .gamma. dipoles. The coil has an inner coil section, defined by a first leg or ring (92) and a second leg or ring (94), which is tuned by added capacitance substantially to the resonance frequency of the low .gamma. dipole. A first outer coil section which is defined by a third leg or ring (90) and the first leg or ring. A second outer coil section defined by the second leg or ring (94) and a fourth leg or ring (96). The first and second outer sections, together with the inner coil section define a coil which has a co-rotating mode and a counter-rotating mode. Added capacitance is sized such that one of the co-rotating and counter-rotating modes is at the high .gamma. resonance frequencies. In this manner, a multiply-tuned radio frequency coil is defined which is simultaneously tuned to at least two resonance frequencies. Separate pick-ups (130, 132) for the high and low resonance frequencies enable both signals to be received (66, 70) simultaneously for reconstruction (74) into image representations.

摘要翻译： 磁共振系统用于激发高伽马偶极子（例如氢）和较低伽马偶极子（例如磷），以同时谐振。 多重调谐射频线圈（40）围绕感兴趣的区域设置。 多调谐射频线圈被调谐到高伽马偶极子的共振频率和低伽马偶极子的共振频率。 线圈具有由第一腿或环（92）和第二腿或环（94）限定的内部线圈段，其通过基本上与低伽马偶极子的谐振频率相加的电容来调谐。 由第三腿或环（90）和第一腿或环限定的第一外部线圈段。 由第二支腿或环（94）和第四支腿或环（96）限定的第二外线圈段。 第一和第二外部部分与内部线圈部分一起限定具有同向旋转模式和反向旋转模式的线圈。 增加的电容的尺寸使得同向旋转模式和反向旋转模式之一处于高伽马共振频率。 以这种方式，定义了被调谐到至少两个谐振频率的多调谐射频线圈。 用于高和低共振频率的单独拾取（130,132）使得两个信号能够同时被接收（66,70）用于重建（74）成图像表示。

公开(公告)号：US5664568A

公开(公告)日：1997-09-09

申请号：US512722

申请日：1995-08-08

申请人： Ravi Srinivasan ,  Robert G. Henderson ,  Robert A. Elek

发明人： Ravi Srinivasan ,  Robert G. Henderson ,  Robert A. Elek

IPC分类号： A61B5/055 ,  G01R33/34 ,  G01R33/36

CPC分类号： G01R33/3657 ,  G01R33/34046 ,  G01R33/34007 ,  G01R33/3685

摘要： A coil assembly (40) includes a first, birdcage type head coil assembly (42) dimensioned to receive a patient's head and a second, neck coil assembly (44) including an anterior coil portion (44a) and a posterior coil portion (44b) dimensioned to receive the patient's neck region. The head and neck coils are partially overlapped. A first cable extends (98a) from the anterior coil portion past the birdcage head coil assembly and a second coaxial cable (98b) extends from the posterior portion past the birdcage head coil assembly. A first decoupling circuit (104a) is disposed in the first coaxial cable beyond a guard ring (106) and a second decoupling circuit (104b) is disposed in the second coaxial cable adjacent the region of overlap between the head and neck coil assemblies. The decoupling circuits are positioned and tuned to prevent radio frequency communication along the coaxial cable sheath between the head and neck coil assemblies. The head and neck coil assemblies are mounted in the mechanical housing which is openable such that an upper half of the guard ring and the birdcage coil and the anterior coil are removable as a unit from the lower half of the guard ring and birdcage coil and the posterior neck coil to facilitate patient access.

摘要翻译： 线圈组件（40）包括第一鸟笼型头部线圈组件（42），其尺寸设置成接收病人的头部;以及包括前部线圈部分（44a）和后部线圈部分（44b）的第二颈部线圈组件（44） 尺寸用于接收患者的颈部区域。 头颈部线圈部分重叠。 第一缆线从前线圈部分延伸穿过鸟笼头线圈组件（98a），并且第二同轴电缆（98b）从后部延伸穿过鸟笼头线圈组件。 第一去耦电路（104a）设置在第一同轴电缆中超过保护环（106），并且第二去耦电路（104b）设置在邻近头颈线圈组件之间的重叠区域的第二同轴电缆中。 去耦电路被定位和调谐以防止头颈线圈组件之间沿同轴电缆护套的射频通信。 头颈线圈组件安装在机械壳体中，其可打开，使得保护环的上半部分和鸟笼线圈和前线圈作为一个单元可从保护环和鸟笼线圈的下半部分移除，并且 后颈线圈以方便患者进入。

公开(公告)号：US5543711A

公开(公告)日：1996-08-06

申请号：US343635

申请日：1994-11-22

申请人： Ravi Srinivasan ,  Robert A. Elek ,  Haiying Liu

发明人： Ravi Srinivasan ,  Robert A. Elek ,  Haiying Liu

IPC分类号： G01R33/34 ,  G01V3/00

CPC分类号： G01R33/34046

摘要： A birdcage coil (42) and a quadrature coil pair which are disposed in a partially overlapping but electrically isolated relationship within a static magnetic field generated by a main field magnet (10). The birdcage coil preferably has twelve legs, has eight-fold symmetry, and is tuned to have two linear modes aligned with first and second orthogonal axes. The quadrature coil includes a first or upper coil portion (90) having an even-number of legs and a mode aligned with a third axis. A second or bottom quadrature coil (92) has an odd-number of legs and has a mode which is aligned with a fourth axis, preferably orthogonal to the third axis. Received resonance signals of the two modes of the birdcage coil are combined (66) and digitized (64); resonance signals received in the first and second modes of the quadrature coil pair are combined (66) and digitized (64). The digitized magnetic resonance signals are reconstructed (72) into an image representation, selective portions of which are displayed on a video monitor (52). Biasing voltages (106) are selectively applied to the birdcage and quadrature coils in order to deactivate one of the coils such that only the other coil receives resonance signals.

摘要翻译： 在由主磁场磁体（10）产生的静态磁场内以部分重叠但电隔离的关系设置的鸟笼线圈（42）和正交线圈对。 鸟笼线圈优选地具有十二个腿部，具有八对称性，并被调谐为具有与第一和第二正交轴对准的两个线性模式。 正交线圈包括具有偶数个腿的第一或上部线圈部分（90）和与第三轴对齐的模式。 第二或下部正交线圈（92）具有奇数个腿部，并且具有与第四轴线对准的模式，优选地与第三轴线正交。 鸟笼线圈的两种模式的接收共振信号被组合（66）并数字化（64）; 在正交线圈对的第一和第二模式中接收的谐振信号被组合（66）并数字化（64）。 将数字化的磁共振信号重建（72）成图像表示，其选择性部分显示在视频监视器（52）上。 偏置电压（106）被选择性地施加到鸟笼和正交线圈，以便去激活线圈中的一个，使得只有另一个线圈接收到谐振信号。