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58 条记录 (耗时 0.018 秒)

    Correction for gradient amplifier hysteresis in acquired MRI data
    1.
    发明授权
    Correction for gradient amplifier hysteresis in acquired MRI data 有权
    获取MRI数据中梯度放大器迟滞的校正

    公开(公告)号：US06291997B1

    公开(公告)日：2001-09-18

    申请号：US09452440

    申请日：1999-12-02

    申请人： Kevin F. King ,  Alexander Ganin ,  Neville D. Gai

    发明人： Kevin F. King ,  Alexander Ganin ,  Neville D. Gai

    IPC分类号： G01V300

    CPC分类号： G01R33/56518 ,  G01R33/3852

    摘要： Image artifacts produced by residual magnetization in elements of the gradient field amplifier system are reduced by driving the residual magnetization to a preselected value at the end of each imaging pulse sequence. Reset gradient pulses are produced by the gradient field amplifier system after each signal is acquired to drive the residual magnetization to a selected value. A number of different reset gradient waveforms may be used, and they may be produced in a number of different ways.

    摘要翻译： 通过在每个成像脉冲序列结束时将残余磁化驱动到预选值，减少梯度场放大器系统的元件中由残余磁化产生的图像伪影。 在获取每个信号之后，由梯度场放大器系统产生复位梯度脉冲以将剩余磁化驱动到所选择的值。 可以使用多个不同的复位梯度波形，并且它们可以以多种不同的方式产生。

    MRI system with modular gradient system
    2.
    发明授权
    MRI system with modular gradient system 失效
    具有模块梯度系统的MRI系统

    公开(公告)号：US06466017B1

    公开(公告)日：2002-10-15

    申请号：US09453274

    申请日：1999-12-02

    申请人： Alexander Ganin ,  Kevin F. King

    发明人： Alexander Ganin ,  Kevin F. King

    IPC分类号： G01V300

    CPC分类号： G01R33/482

    摘要： A magnetic resonance imaging system has a primary set of whole-body gradient coils and a supplemental set of gradient coils. The supplemental gradient coils are employed to produce imaging gradients when fast imaging pulse sequences are performed, and the primary set of gradient coils are employed when interleaved saturation or navigator signals pulse sequences are performed during a scan.

    摘要翻译： 磁共振成像系统具有一组全身梯度线圈和一组补充梯度线圈。 当执行快速成像脉冲序列时，补充梯度线圈用于产生成像梯度，并且当在扫描期间执行交错饱和度或导航信号脉冲序列时采用梯度线圈的主要集合。

    Method and apparatus for calibration of RF and gradient field time delays
    4.
    发明授权
    Method and apparatus for calibration of RF and gradient field time delays 有权
    用于校准RF和梯度场时间延迟的方法和装置

    公开(公告)号：US06288545B1

    公开(公告)日：2001-09-11

    申请号：US09274468

    申请日：1999-03-22

    申请人： Kevin F. King ,  Alexander Ganin

    发明人： Kevin F. King ,  Alexander Ganin

    IPC分类号： G01V300

    CPC分类号： G01R33/58

    摘要： A technique is disclosed for calibrating time delays between RF and gradient frequency pulses in a magnetic resonance imaging system. The calibration procedure includes the formation of calibration images of a phantom positioned in the gradient field system. Calibration images are processed and compared to one another to determine deviation between locations in the gradient field system and the impact of radio frequency-to-gradient waveform time delays on the deviations. Optimal time delays are identified which minimize the deviations between the calibration images. Multiple axes of the system may be calibrated through the use of symmetrical phantoms and similar pulse sequences of each axis. A spectral-spatial pulse sequence is employed bearing the calibration routine.

    摘要翻译： 公开了一种用于校准磁共振成像系统中RF和梯度频率脉冲之间的时间延迟的技术。 校准过程包括形成位于梯度场系统中的体模的校准图像。 校准图像被处理并相互比较以确定梯度场系统中的位置之间的偏差以及射频到梯度波形时间延迟对偏差的影响。 识别最佳时间延迟，其最小化校准图像之间的偏差。 可以通过使用每个轴的对称体模和类似的脉冲序列校准系统的多个轴。 采用校准程序的谱空间脉冲序列。

    Modular gradient system for MRI system
    6.
    发明授权
    Modular gradient system for MRI system 失效
    MRI系统模块化梯度系统

    公开(公告)号：US06313630B1

    公开(公告)日：2001-11-06

    申请号：US09382905

    申请日：1999-08-25

    申请人： Alexander Ganin ,  Kevin F. King

    发明人： Alexander Ganin ,  Kevin F. King

    IPC分类号： G01U300

    CPC分类号： G01R33/385 ,  G01R33/3852

    摘要： An MRI system has two sets of gradient coils driven by two corresponding sets of gradient amplifiers. Logical gradient waveforms produced during a pulse sequence are rotated to produce corresponding physical gradient waveforms and these are distributed to drive both sets of coils simultaneously. Each distributed set of physical gradient waveforms is separately compensated for Eddy current errors, and a polarizing field Eddy current compensation signal is produced and used to modulate the RF reference frequency of the system transceiver.

    摘要翻译： MRI系统具有由两组对应的梯度放大器驱动的两组梯度线圈。 在脉冲序列期间产生的逻辑梯度波形被旋转以产生相应的物理梯度波形，并且它们被分配以同时驱动两组线圈。 每个分布的物理梯度波形组分别补偿涡流电流误差，并产生偏振场涡流补偿信号，并用于调制系统收发器的RF参考频率。

    Automatic measurement of gradient field distortion
    7.
    发明授权
    Automatic measurement of gradient field distortion 失效
    自动测量梯度场失真

    公开(公告)号：US06211675B1

    公开(公告)日：2001-04-03

    申请号：US09191862

    申请日：1998-11-12

    申请人： Alexander Ganin ,  Kevin F. King

    发明人： Alexander Ganin ,  Kevin F. King

    IPC分类号： G01V300

    CPC分类号： G01R33/56518 ,  G01R33/58

    摘要： An MRI system automatically performs a calibration procedure to calculate optimal compensation parameter values for all three gradient pre-emphasis filters. A single fixture is employed to measure the errors caused by gradient pulses produced by each of the three gradient systems. The measured errors are used to calculate a gradient error function and the optimal compensation parameter values are calculated for each pre-emphasis filter by finding the minimum in the gradient error function.

    摘要翻译： MRI系统自动执行校准程序，以计算所有三个梯度预加重滤波器的最佳补偿参数值。 采用单个夹具来测量由三个梯度系统中的每一个产生的梯度脉冲引起的误差。 测量误差用于计算梯度误差函数，并通过求出梯度误差函数中的最小值，为每个预加重滤波器计算最优补偿参数值。

    Method for compensating an MRI system for time dependent gradient field distortion
    8.
    发明授权
    Method for compensating an MRI system for time dependent gradient field distortion 失效
    用于补偿MRI系统的时间依赖梯度场失真的方法

    公开(公告)号：US6025715A

    公开(公告)日：2000-02-15

    申请号：US990610

    申请日：1997-12-15

    申请人： Kevin F. King ,  Alexander Ganin

    发明人： Kevin F. King ,  Alexander Ganin

    IPC分类号： G01R33/387 ,  A61B5/055 ,  G01R33/385 ,  G01R33/48 ,  G01V3/00

    CPC分类号： G01R33/385

    摘要： An MRI system performs a calibration procedure to calculate optimal compensation parameter values for a pre-emphasis filter that alters the shape of gradient waveforms. The gradient field errors are measured using a series of pulse sequences in which different compensation parameter values are sampled. The measured errors are used to calculate a gradient error function and the optimal compensation parameter values are calculated by finding the minimum in the gradient error function.

    摘要翻译： MRI系统执行校准程序，以计算改变梯度波形形状的预加重滤波器的最佳补偿参数值。 使用其中对不同的补偿参数值进行采样的一系列脉冲序列来测量梯度场误差。 测量误差用于计算梯度误差函数，并通过求出梯度误差函数中的最小值来计算最优补偿参数值。

    SYSTEM AND METHOD FOR MULTI-SPECTRAL MR IMAGING NEAR METAL
    9.
    发明申请
    SYSTEM AND METHOD FOR MULTI-SPECTRAL MR IMAGING NEAR METAL 有权
    用于多金属MR成像的系统和方法

    公开(公告)号：US20100308827A1

    公开(公告)日：2010-12-09

    申请号：US12860272

    申请日：2010-08-20

    申请人： Kevin M. Koch ,  Kevin F. King ,  Graeme C. McKinnon ,  Brian Hargreaves

    发明人： Kevin M. Koch ,  Kevin F. King ,  Graeme C. McKinnon ,  Brian Hargreaves

    IPC分类号： G01R33/48

    CPC分类号： G01R33/56563 ,  G01R33/243 ,  G01R33/4822 ,  G01R33/5608

    摘要： A system and method for multi-spectral MR imaging near metal include a computer programmed to calculate an MR pulse sequence comprising a plurality of RF pulses configured to excite spins in an imaging object and comprising a plurality of volume selection gradients and determine a plurality of distinct offset frequency values. For each respective determined offset frequency value, the computer is programmed to execute the MR pulse sequence having a central transmit frequency and a central receive frequency of the MR pulse sequence set to the respective determined offset frequency value. The computer is also programmed to acquire a three-dimensional (3D) MR data set for each MR pulse sequence execution and generate a composite image based on data from each of the acquired 3D MR data sets.

    摘要翻译： 用于金属附近的多光谱MR成像的系统和方法包括被编程为计算MR脉冲序列的计算机，该计算机包括被配置为激励成像对象中的自旋的多个RF脉冲，并且包括多个体积选择梯度并且确定多个不同的 偏移频率值。 对于每个相应确定的偏移频率值，计算机被编程为执行MR脉冲序列，该MR脉冲序列具有被设置为相应确定的偏移频率值的MR脉冲序列的中心发射频率和中心接收频率。 计算机还被编程为获取每个MR脉冲序列执行的三维（3D）MR数据集，并且基于来自每个获取的3D MR数据集的数据生成合成图像。

    Hybrid k-t method of dynamic imaging with improved spatiotemporal resolution
    10.
    发明授权
    Hybrid k-t method of dynamic imaging with improved spatiotemporal resolution 有权
    动态成像的混合k-t方法具有改进的时空分辨率

    公开(公告)号：US07592809B1

    公开(公告)日：2009-09-22

    申请号：US11287184

    申请日：2005-11-23

    申请人： Kevin F. King ,  Dan Xu ,  Zhi-Pei Liang

    发明人： Kevin F. King ,  Dan Xu ,  Zhi-Pei Liang

    IPC分类号： G01V3/00

    CPC分类号： G01R33/5611 ,  G01R33/56308

    摘要： Variable-density (VD), sequentially-interleaved sampling of k-space coupled with the acquisition of reference frames of data is carried out to improve spatiotemporal resolution, image quality, and signal-to-noise ratio (SNR) of dynamic images. In one example, ktSENSE is implemented with a non-static regularization image, such as that provided by RIGR or similar technique, to acquire and reconstruct dynamic images. The integration of ktSENSE and RIGR, for example, provides dynamic images with higher spatiotemporal resolution and lower image artifacts compared to dynamic images acquired and reconstructed using ktSENSE alone.

    摘要翻译： 执行可变密度（VD），与数据参考帧的采集相结合的k空间的顺序交错采样，以改善动态图像的时空分辨率，图像质量和信噪比（SNR）。 在一个示例中，ktSENSE通过诸如由RIGR或类似技术提供的非静态正则化图像来实现以获取和重建动态图像。 例如，与使用ktSENSE单独获取和重建的动态图像相比，ktSENSE和RIGR的集成提供了具有更高时空分辨率和较低图像伪影的动态图像。