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    • 2. 发明授权
    • System and method for generating a magnetic resonance image using compressed sensing and parallel imaging
    • 使用压缩感测和并行成像产生磁共振图像的系统和方法
    • US08717024B2
    • 2014-05-06
    • US13342857
    • 2012-01-03
    • Kevin F. KingDan Xu
    • Kevin F. KingDan Xu
    • G01R33/44
    • G01R33/5611
    • 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.
    • 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。
    • 4. 发明申请
    • SYSTEM AND METHOD FOR PROSPECTIVE CORRECTION OF HIGH ORDER EDDY-CURRENT-INDUCED DISTORTION IN DIFFUSION-WEIGHTED ECHO PLANAR IMAGING
    • 用于扩展加权ECHO平面成像中高阶EDDY电流诱导失真的前瞻性校正的系统和方法
    • US20120271584A1
    • 2012-10-25
    • US13364003
    • 2012-02-01
    • Dan XuJoseph K. MaierKevin F. KingBruce David Collick
    • Dan XuJoseph K. MaierKevin F. KingBruce David Collick
    • G01R35/00
    • G01R33/56518G01R33/5616G01R33/56341
    • 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.
    • 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。
    • 5. 发明申请
    • SYSTEM AND METHOD FOR PHASE RELAXED RF PULSE DESIGN
    • 相位放大射频脉冲设计的系统与方法
    • US20100264926A1
    • 2010-10-21
    • US12424797
    • 2009-04-16
    • Dan XuKevin F. KingGraeme C. McKinnon
    • Dan XuKevin F. KingGraeme C. McKinnon
    • G01R33/20
    • G01R33/5612
    • 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.
    • 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。
    • 6. 发明授权
    • System and method for amplitude reduction in RF pulse design
    • RF脉冲设计幅度减小的系统和方法
    • US07737690B2
    • 2010-06-15
    • US11750478
    • 2007-05-18
    • Dan XuKevin F. King
    • Dan XuKevin F. King
    • G01V3/00
    • G01R33/4836A61B5/055G01R33/4824G01R33/4833
    • 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.
    • 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。
    • 7. 发明授权
    • System and method for designing multi-channel RF pulses for MR imaging
    • 用于MR成像设计多通道RF脉冲的系统和方法
    • US07466131B1
    • 2008-12-16
    • US11738225
    • 2007-04-20
    • Dan XuKevin F. KingZhi-Pei Liang
    • Dan XuKevin F. KingZhi-Pei Liang
    • G01V3/00
    • G01R33/4836G01R33/4824G01R33/4833
    • 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.
    • 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。
    • 8. 发明申请
    • SYSTEM AND METHOD FOR DESIGNING IMPROVED RF PULSE PROFILES
    • 用于设计改进的RF脉冲轮廓的系统和方法
    • US20080238425A1
    • 2008-10-02
    • US11694617
    • 2007-03-30
    • Dan XuKevin F. KingZhi-Pei Liang
    • Dan XuKevin F. KingZhi-Pei Liang
    • G01R33/32
    • G01R33/4833
    • 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.
    • 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。
    • 9. 发明授权
    • System and method for prospective correction of high order eddy-current-induced distortion in diffusion-weighted echo planar imaging
    • 扩散加权回波平面成像中高阶涡流诱导失真的前瞻性校正系统和方法
    • US08942945B2
    • 2015-01-27
    • US13364003
    • 2012-02-01
    • Dan XuJoseph K. MaierKevin F. KingBruce David Collick
    • Dan XuJoseph K. MaierKevin F. KingBruce David Collick
    • G01R33/565G01R33/563G01R33/561
    • G01R33/56518G01R33/5616G01R33/56341
    • 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.
    • 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。
    • 10. 发明授权
    • Apparatus and method for parallel transmission of RF pulses in a spin echo sequence
    • 用于在自旋回波序列中并行传输RF脉冲的装置和方法
    • US08482281B2
    • 2013-07-09
    • US12752368
    • 2010-04-01
    • Kevin F. KingDan Xu
    • Kevin F. KingDan Xu
    • G01V3/00
    • G01R33/5612G01R33/5617G01R33/5659
    • A method, system, and apparatus including a magnetic resonance imaging (MRI) apparatus that includes an MRI system having a plurality of gradient coils, a radio-frequency (RF) transceiver system, an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly, and a computer. The computer is programmed to implement a spin echo sequence to acquire magnetic resonance (MR) data, where the spin echo sequence includes an excitation RF pulse and at least one refocusing pulse per repetition time (TR) of the excitation pulse. The computer is also programmed to transmit at least two component RF pulses in parallel channels during implementation of the spin echo sequence to produce a first refocusing RF pulse and programmed to reconstruct an image from spin echo sequence image data.
    • 一种包括磁共振成像(MRI)装置的方法,系统和装置,其包括具有多个梯度线圈的MRI系统,射频(RF)收发器系统,由脉冲模块控制的RF开关以发送RF信号 到RF线圈组件和计算机。 计算机被编程以实现自旋回波序列以获取磁共振(MR)数据,其中自旋回波序列包括激励RF脉冲和每个激励脉冲的每个重复时间(TR)的至少一个再聚焦脉冲。 计算机还被编程为在实现自旋回波序列期间在并行通道中传送至少两个分量RF脉冲,以产生第一重聚焦RF脉冲并被编程以从自旋回波序列图像数据重建图像。