公开(公告)号：US4649348A

公开(公告)日：1987-03-10

申请号：US642613

申请日：1984-08-20

申请人： David C. Flugan

发明人： David C. Flugan

IPC分类号： G01R33/34 ,  G01R33/20

CPC分类号： G01R33/34069 ,  G01R33/3657 ,  Y10S505/844

摘要： A family of high Q radio frequency coils for an NMR imaging system is provided. The coil family includes a transmitting coil for transmitting an r.f. field aligned with a given plane. The transmitting coil is used with one of the described receiving coils, each of which is responsive to NMR signals in a plane oriented orthogonally to said given plane. The receiving coils employ an open, arcuate configuration, which alleviates sensations of confinement characteristic of fully enclosing coil forms. Arcuate sections of the receiving coils are curved away from the patient, to decrease signal reception at areas from which meaningful signals cannot be gathered. To prevent interaction between the transmitting and receiving coils, means are provided for rendering each coil nonresponsive to NMR and radio signal frequencies when the coils are not being operated.

摘要翻译： 提供了一个用于NMR成像系统的高Q射频线圈系列。 线圈系列包括用于传输r.f的发射线圈。 场与给定平面对齐。 发射线圈与所述接收线圈中的一个一起使用，每个接收线圈在与所述给定平面正交定向的平面中响应于NMR信号。 接收线圈采用开放的弓形结构，其减轻完全包围线圈形式的限制特性的感觉。 接收线圈的弧形部分从患者身体弯曲，以减少无法收集有意义的信号的区域的信号接收。 为了防止发送和接收线圈之间的相互作用，提供了当线圈未被操作时使每个线圈不响应于NMR和无线电信号频率的装置。

公开(公告)号：US5170123A

公开(公告)日：1992-12-08

申请号：US392649

申请日：1989-08-11

申请人： G. Neil Holland ,  Douglas M. Blakeley ,  John R. Stauber ,  David C. Flugan ,  Kenneth S. Denison

发明人： G. Neil Holland ,  Douglas M. Blakeley ,  John R. Stauber ,  David C. Flugan ,  Kenneth S. Denison

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

CPC分类号： G01R33/3607

摘要： A magnetic resonance imaging apparatus includes one or more digital transmitters (B), one or more digital receivers (C), and digital data processing circuitry (D) which are all clocked and controlled by a single clock (F). Each digital transmitter includes a numerically controlled modulated oscillator (20) which processes digital phase and frequency signals to produce an output which addresses a wave-form map stored in a PROM (22). Each wave-form output of the PROM is multiplied (24) by a digital amplitude profile signal to generate a phase, frequency, and amplitude modulated digital RF signals. A clock gate (30) controls clocking of the digital modulation to create RF pulses. A digital-to-analog converter (28) converts the digital information to an analog RF pulse which is applied to a subject in an image region. The receivers each include an analog-to-digital converter (60) which digitizes the magnetic resonance signal emanating from the subject in the image region with four fold oversampling. A pair of FIR filters (62a, 62b) multiply the digital resonance signal by digital sine and cosine filter coefficients to create in-phase and out-of-phase digital magnetic resonance signal components. After additional digital filtering (64a, 64b), the digital in-phase and quadrature components are Fourier transformed (70) and accumulated in an image memory (72) to form an image representation.

公开(公告)号：US4717881A

公开(公告)日：1988-01-05

申请号：US798669

申请日：1985-11-15

申请人： David C. Flugan

发明人： David C. Flugan

IPC分类号： G01R33/34 ,  G01R33/36 ,  G01R33/20

CPC分类号： G01R33/3657 ,  G01R33/34069 ,  G01R33/3628 ,  G01R33/3671

摘要： Radio frequency apparatus for a magnetic resonance system is provided which includes an r.f. coil and DC controlled circuitry for selectively altering the characteristics of the coil. A loading coil is provided which is selectively activated to de-Q the coil during r.f. transmission so as to minimize the loading effects of the subject and their effect on coil impedance. A switched network is provided which selectively destroys the normal resonant condition of the coil when a second r.f. coil is operative to minimize interaction between the two coils.

摘要翻译： 提供了一种用于磁共振系统的射频装置，其包括一个r.f. 线圈和直流控制电路，用于选择性地改变线圈的特性。 提供一个加载线圈，其被选择性地激活以在r.f期间使线圈去Q。 传输，以最小化被摄体的负载效应及其对线圈阻抗的影响。 提供了一种交换网络，其选择性地破坏线圈的正常谐振状态，当第二r.f. 线圈可操作以最小化两个线圈之间的相互作用。

公开(公告)号：US5323776A

公开(公告)日：1994-06-28

申请号：US961150

申请日：1992-10-15

申请人： Douglas M. Blakeley ,  Robert C. Gauss ,  David C. Flugan

发明人： Douglas M. Blakeley ,  Robert C. Gauss ,  David C. Flugan

IPC分类号： A61B5/024 ,  G01R33/465 ,  A61B5/0245 ,  A61B5/055

CPC分类号： G01R33/465 ,  A61B5/02416 ,  Y10S128/901

摘要： Magnetic resonance imaging hardware (A) defines a patient receiving region (20) that is surrounded by a bore liner (22). A socket (50) is mounted in the bore liner with an appropriate receptacle for receiving a standard plug (52) of a conventional pulse oximetry system. Conventional pulse oximetry systems include a sensor unit (54) connected with a cable (56) having the plug (52) at one end thereof. A notch filter (62) attenuates currents near the resonance frequency of the imager. A preamplifier (60) amplifies signals from the sensor unit. Within the shielding (66) of the preamplifier, a low pass filter (68) is provided to remove induced radio frequency components from the preamplified sensor unit signal. A radio frequency filter (70) mounted at the shield of the shielded room (B) prevents radio frequency signals from reaching an exterior processing and display unit (E) and prevents radio frequency signals from a clock (72) of the processing and display unit from being conveyed into the shielded room (B). The processing and display unit processes the signal received from the preamplifier to generate a pulse rate display (78) and a blood oxygen concentration display (80).

摘要翻译： 磁共振成像硬件（A）限定由孔衬套（22）包围的患者接收区域（20）。 插座（50）用适当的插座安装在孔衬里中，用于接收常规脉搏血氧仪系统的标准插头（52）。 传统的脉搏血氧饱和度测量系统包括与其一端具有插头（52）的电缆（56）连接的传感器单元（54）。 陷波滤波器（62）衰减成像器谐振频率附近的电流。 前置放大器（60）放大来自传感器单元的信号。 在前置放大器的屏蔽（66）内，提供了一个低通滤波器（68），以从前置放大的传感器单元信号中去除感应射频分量。 安装在屏蔽室（B）的屏蔽处的射频滤波器（70）防止射频信号到达外部处理和显示单元（E），并防止来自处理和显示单元的时钟（72）的射频信号 从被传送到屏蔽室（B）。 处理和显示单元处理从前置放大器接收的信号以产生脉搏率显示（78）和血氧浓度显示（80）。

公开(公告)号：US4585995A

公开(公告)日：1986-04-29

申请号：US601897

申请日：1984-04-19

申请人： David C. Flugan

发明人： David C. Flugan

IPC分类号： G01R33/385 ,  G01R33/421 ,  G01R33/22

CPC分类号： G01R33/385 ,  G01R33/421

摘要： Compensation is provided for a gradient field of an NMR imaging system which compensates for the effects of eddy fields developed in the static magnetic field from metallic components during gradient field switching. The compensation comprises providing current overshoot to the gradient coil during gradient switching. The overshoot current decays with a time constant chosen to substantially offset the decay of eddy fields following gradient switching. In a preferred embodiment, a time constant network representative of eddy field decay is coupled in combination with a feedback signal from a current sampling resistor of the gradient coil.

摘要翻译： 为NMR成像系统的梯度场提供补偿，补偿了梯度场切换期间来自金属成分的静磁场中产生的涡流的影响。 补偿包括在梯度切换期间向梯度线圈提供电流过冲。 过冲电流衰减时间常数，以选择梯度切换以大体上抵消涡流衰减。 在优选实施例中，代表涡流衰减的时间常数网络与来自梯度线圈的电流采样电阻器的反馈信号相结合。