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。

公开(公告)号：US07466131B1

公开(公告)日：2008-12-16

申请号：US11738225

申请日：2007-04-20

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

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

IPC分类号： G01V3/00

CPC分类号： G01R33/4836 ,  G01R33/4824 ,  G01R33/4833

摘要： A system and method are provided for designing RF pulses for multi-channel and/or multi-dimensional spatially-selective applications using a linear approximation. Embodiments of the system and method may use a generalized linear-class large tip angle approximation to design RF pulses for multi-channel and parallel transmission. Further, some of these approximations allow for the design of arbitrarily large flip angles, irregularly-shaped flip angle profiles, or arbitrary initial magnetization values. Embodiments of the system and method may also provide for the design of k-space trajectories which aid in maintaining assumptions of the various linear class approximations.

摘要翻译： 提供了一种系统和方法，用于使用线性近似来设计用于多通道和/或多维空间选择性应用的RF脉冲。 该系统和方法的实施例可以使用广义线性级大尖角近似来设计用于多通道和并行传输的RF脉冲。 此外，这些近似中的一些允许设计任意大的翻转角，不规则形状的翻转轮廓或任意的初始磁化值。 系统和方法的实施例还可以提供有助于维持各种线性类近似的假设的k空间轨迹的设计。

公开(公告)号：US20080238425A1

公开(公告)日：2008-10-02

申请号：US11694617

申请日：2007-03-30

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

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

IPC分类号： G01R33/32

CPC分类号： G01R33/4833

摘要： A system and method are provided for designing RF pulses which have improved magnetization profiles. By utilizing an optimal control approach as an alternative to, or in combination with, non-iterative approximations, RF pulses generated by the system and method described herein will exhibit less deviation from that of “ideal” Bloch solutions. Consequently, the magnetization profiles produced by the RF pulses generated by the system and method described herein will be closer to the desired profiles. In addition, limitations of non-iterative approximations, such as maximum tip angle limits and linearity constraints, can be avoided.

摘要翻译： 提供了一种用于设计具有改进的磁化分布的RF脉冲的系统和方法。 通过利用最优控制方法作为非迭代近似的替代方案或与非迭代近似组合，由本文描述的系统和方法产生的RF脉冲将表现出与“理想”Bloch解决方案的偏差较小的偏差。 因此，由本文所述的系统和方法产生的RF脉冲产生的磁化曲线将更接近所需的轮廓。 此外，可以避免非迭代近似的限制，例如最大尖角限制和线性约束。

公开(公告)号：US07705594B2

公开(公告)日：2010-04-27

申请号：US11694617

申请日：2007-03-30

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

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

IPC分类号： G01V3/00

CPC分类号： G01R33/4833

摘要： A system and method are provided for designing RF pulses which have improved magnetization profiles. By utilizing an optimal control approach as an alternative to, or in combination with, non-iterative approximations, RF pulses generated by the system and method described herein will exhibit less deviation from that of “ideal” Bloch solutions. Consequently, the magnetization profiles produced by the RF pulses generated by the system and method described herein will be closer to the desired profiles. In addition, limitations of non-iterative approximations, such as maximum tip angle limits and linearity constraints, can be avoided.

摘要翻译： 提供了一种用于设计具有改进的磁化分布的RF脉冲的系统和方法。 通过利用最优控制方法作为非迭代近似的替代方案或与非迭代近似组合，由本文描述的系统和方法产生的RF脉冲将显示出与“理想”Bloch解决方案的偏差较小的偏差。 因此，由本文所述的系统和方法产生的RF脉冲产生的磁化曲线将更接近所需的轮廓。 此外，可以避免非迭代近似的限制，例如最大尖角限制和线性约束。

公开(公告)号：US08717024B2

公开(公告)日：2014-05-06

申请号：US13342857

申请日：2012-01-03

申请人： Kevin F. King ,  Dan Xu

发明人： Kevin F. King ,  Dan Xu

IPC分类号： G01R33/44

CPC分类号： G01R33/5611

摘要： A method for generating a magnetic resonance image includes acquiring a first k-space data set from each of a plurality of RF coils. The first k-space data set includes calibration data and randomly undersampled data. For each RF coil, a fully randomly sampled k-space data set is generated by removing a portion of the calibration data. A compressed sensing reconstruction technique is applied to the fully randomly sampled k-space data set to generate an aliased image, which is used to generate a uniformly undersampled k-space data set. A second k-space data set is generated by inserting the portion of the calibration data and a parallel imaging reconstruction technique is applied to the second k-space data set to synthesize unacquired data. The second k-space data set and the synthesized data are combined to generate a complete k-space data set for the RF coil.

摘要翻译： 用于产生磁共振图像的方法包括从多个RF线圈中的每一个获取第一k空间数据集。 第一个k空间数据集包括校准数据和随机欠采样数据。 对于每个RF线圈，通过去除一部分校准数据来生成完全随机采样的k空间数据集。 将压缩感测重构技术应用于完全随机采样的k空间数据集，以生成用于生成统一欠采样的k空间数据集的混叠图像。 通过插入校准数据的一部分来生成第二k空间数据集，并且将并行成像重构技术应用于第二k空间数据集合以合成未查询的数据。 第二k空间数据组和合成数据被组合以产生用于RF线圈的完整的k空间数据集。

公开(公告)号：US08680860B2

公开(公告)日：2014-03-25

申请号：US12962945

申请日：2010-12-08

申请人： Dan Xu ,  Jian Zhang ,  Richard Scott Hinks ,  Kevin F. King

发明人： Dan Xu ,  Jian Zhang ,  Richard Scott Hinks ,  Kevin F. King

IPC分类号： G01V3/00

CPC分类号： G01R33/4838 ,  G01R33/5607

摘要： A system and method is disclosed for eliminating localized fluctuation artifacts caused by fat signal contamination in MR images, the system includes a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a bore of a magnet, and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images, and a computer programmed to apply a spectral-spatial fat saturation pulse, apply a slice selection gradient pulse, acquire imaging data of an imaging slice of interest, and generate an image.

摘要翻译： 公开了一种用于消除由MR图像中的脂肪信号污染引起的局部波动伪影的系统和方法，该系统包括具有围绕磁体的孔定位的多个梯度线圈的磁共振成像（MRI）系统，以及RF收发器系统 以及由脉冲模块控制的RF开关以将RF信号传输到RF线圈组件以获取MR图像，以及被编程为应用频谱 - 空间脂肪饱和脉冲的计算机，应用切片选择梯度脉冲，获取成像的成像数据 切片感兴趣，并生成图像。

公开(公告)号：US20120271584A1

公开(公告)日：2012-10-25

申请号：US13364003

申请日：2012-02-01

申请人： Dan Xu ,  Joseph K. Maier ,  Kevin F. King ,  Bruce David Collick

发明人： Dan Xu ,  Joseph K. Maier ,  Kevin F. King ,  Bruce David Collick

IPC分类号： G01R35/00

CPC分类号： G01R33/56518 ,  G01R33/5616 ,  G01R33/56341

摘要： A computer is programmed to acquire calibration data from a calibration scan, the calibration data configured to characterize high order eddy current (HOEC) generated magnetic field error of an imaging system. The computer is also programmed to process the calibration data to generate a plurality of basis coefficients and a plurality of time constants and to calculate a plurality of basis correction coefficients based on the plurality of basis coefficients, the plurality of time constants, and gradient waveforms in a given pulse sequence. The computer is further programmed to execute a diffusion-weighted imaging scan that comprises application of a DW-EPI pulse sequence to acquire MR data from an imaging subject and reconstruction of an image based on the acquired MR data. The computer is also programmed to apply HOEC-generated magnetic field error correction during application of the DW-EPI pulse sequence configured to reduce HOEC-induced distortion in the reconstructed image.

摘要翻译： 计算机被编程为从校准扫描获取校准数据，校准数据被配置为表征成像系统产生的高阶涡流（HOEC）产生的磁场误差。 计算机还被编程为处理校准数据以产生多个基准系数和多个时间常数，并且基于多个基准系数，多个时间常数和梯度波形来计算多个基准校正系数 给定的脉冲序列。 计算机还被编程为执行扩散加权成像扫描，其包括应用DW-EPI脉冲序列以从成像对象获取MR数据并且基于所获取的MR数据重建图像。 计算机还被编程为在应用DW-EPI脉冲序列期间应用HOEC产生的磁场误差校正，其被配置为减少重建图像中HOEC引起的失真。

公开(公告)号：US20100264926A1

公开(公告)日：2010-10-21

申请号：US12424797

申请日：2009-04-16

申请人： Dan Xu ,  Kevin F. King ,  Graeme C. McKinnon

发明人： Dan Xu ,  Kevin F. King ,  Graeme C. McKinnon

IPC分类号： G01R33/20

CPC分类号： G01R33/5612

摘要： Techniques for designing RF pulses may be configured to produce improved magnitude profiles of the resulting magnetization by relaxing the phase constraint and optimizing the phase profiles. In one embodiment, a spinor-based, optimal control, optimal phase technique may be used to design arbitrary-tip-angle (e.g., large and small tip angle) RF pulses (both parallel transmission and single channel). In another embodiment, small tip angle RF pulses (both parallel transmission and single channel) may be designed using a small-tip-angle (STA) pulse design without phase constraint that is formulated as a parameter optimization problem.

摘要翻译： 用于设计RF脉冲的技术可以被配置为通过放松相位约束并优化相位曲线来产生所得到的磁化的改善的幅度分布。 在一个实施例中，可以使用基于旋转器的最优控制最佳相位技术来设计任意尖角（例如，大和小尖角）RF脉冲（并行传输和单通道）。 在另一个实施例中，可以使用没有相位约束的小尖角（STA）脉冲设计来设计小尖端角度RF脉冲（并行传输和单通道），其被配置为参数优化问题。

公开(公告)号：US07737690B2

公开(公告)日：2010-06-15

申请号：US11750478

申请日：2007-05-18

申请人： Dan Xu ,  Kevin F. King

发明人： Dan Xu ,  Kevin F. King

IPC分类号： G01V3/00

CPC分类号： G01R33/4836 ,  A61B5/055 ,  G01R33/4824 ,  G01R33/4833

摘要： A system and method are provided for adjusting RF pulses and gradient waveforms to reduce B1 field magnitude in MR imaging sequences. When an RF pulse is presented which has a high amplitude segment that would exceed a maximum B1 magnitude, the system and method provided herein can apply a variable slew rate design technique. A slew rate of at least one gradient waveform can be varied to reduce a B1 field magnitude during transmission of the high amplitude segment of the RF pulse. By controlling the slew rate of gradient waveforms for non-Cartesian k-space trajectories according to a calculated maximum allowable slew rate function, embodiments of the system and method can, in effect, reduce gradient amplitude.

摘要翻译： 提供了一种用于调整RF脉冲和梯度波形以减少MR成像序列中的B1场强的系统和方法。 当提供具有超过最大B1幅度的高幅度段的RF脉冲时，本文提供的系统和方法可以应用可变转换速率设计技术。 可以改变至少一个梯度波形的转换速率，以在RF脉冲的高幅度段的传输期间减小B1场幅度。 通过根据计算出的最大允许转换速率函数控制非笛卡尔k空间轨迹的梯度波形的转换速率，该系统和方法的实施例实际上可以减小梯度幅度。

公开(公告)号：US08942945B2

公开(公告)日：2015-01-27

申请号：US13364003

申请日：2012-02-01

申请人： Dan Xu ,  Joseph K. Maier ,  Kevin F. King ,  Bruce David Collick

发明人： Dan Xu ,  Joseph K. Maier ,  Kevin F. King ,  Bruce David Collick

IPC分类号： G01R33/565 ,  G01R33/563 ,  G01R33/561

CPC分类号： G01R33/56518 ,  G01R33/5616 ,  G01R33/56341

摘要： A computer is programmed to acquire calibration data from a calibration scan, the calibration data configured to characterize high order eddy current (HOEC) generated magnetic field error of an imaging system. The computer is also programmed to process the calibration data to generate a plurality of basis coefficients and a plurality of time constants and to calculate a plurality of basis correction coefficients based on the plurality of basis coefficients, the plurality of time constants, and gradient waveforms in a given pulse sequence. The computer is further programmed to execute a diffusion-weighted imaging scan that comprises application of a DW-EPI pulse sequence to acquire MR data from an imaging subject and reconstruction of an image based on the acquired MR data. The computer is also programmed to apply HOEC-generated magnetic field error correction during application of the DW-EPI pulse sequence configured to reduce HOEC-induced distortion in the reconstructed image.

摘要翻译： 计算机被编程为从校准扫描获取校准数据，校准数据被配置为表征成像系统产生的高阶涡流（HOEC）产生的磁场误差。 计算机还被编程为处理校准数据以产生多个基准系数和多个时间常数，并且基于多个基准系数，多个时间常数和梯度波形来计算多个基准校正系数 给定的脉冲序列。 计算机还被编程为执行扩散加权成像扫描，其包括应用DW-EPI脉冲序列以从成像对象获取MR数据并且基于所获取的MR数据重建图像。 计算机还被编程为在应用DW-EPI脉冲序列期间应用HOEC产生的磁场误差校正，其被配置为减少重建图像中HOEC引起的失真。