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1.发明申请Coil Array Mode Compression For Parallel Transmission Magnetic Resonance Imaging 有权线圈阵列模式压缩用于并行传输磁共振成像公开(公告)号：US20100052679A1
公开(公告)日：2010-03-04
申请号：US12550074
申请日：2009-08-28
IPC分类号： G01R33/48
CPC分类号： G01R33/5611 , G01R33/3664 , G01R33/4833 , G01R33/4836 , G01R33/5612
摘要： A method for target-dependent, sparsity-enforced selection for choosing a substantially optimal connection of radiofrequency (“RF”) transmitters to the elements of the RF coil array is provided. In particular, a method is provided that selects the linear combinations of the “N” spatial mode profiles of a transmission RF coil array, such that the k-space trajectory and pulse duration acceleration capabilities of the array are advantageously utilized. A sparsity-enforcement method that determines a subset of the available spatial modes for a parallel transmission RF coil array is employed to this end. In this manner, the utilization of the encoding power of a highly-parallel N-mode coil array in a system with only “P” available excitation channels is enabled.
摘要翻译： 提供了用于选择用于选择射频（RF））发射机到RF线圈阵列的元件的基本上最佳连接的目标依赖，稀疏执行选择的方法。 具体地，提供了一种选择发射RF线圈阵列的“N”个空间模式分布的线性组合的方法，使得有利地利用阵列的k空间轨迹和脉冲持续时间加速能力。 为此，采用了稀疏执行方法来确定并行传输RF线圈阵列的可用空间模式的子集。 以这种方式，能够在仅具有“P”可用激励信道的系统中利用高并行N模式线圈阵列的编码功率。
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2.发明授权Coil array mode compression for parallel transmission magnetic resonance imaging 有权线圈阵列模式压缩用于并行传输磁共振成像公开(公告)号：US08085046B2
公开(公告)日：2011-12-27
申请号：US12550074
申请日：2009-08-28
IPC分类号： G01V3/00
CPC分类号： G01R33/5611 , G01R33/3664 , G01R33/4833 , G01R33/4836 , G01R33/5612
摘要： A method for target-dependent, sparsity-enforced selection for choosing a substantially optimal connection of radiofrequency (“RF”) transmitters to the elements of the RF coil array is provided. In particular, a method is provided that selects the linear combinations of the “N” spatial mode profiles of a transmission RF coil array, such that the k-space trajectory and pulse duration acceleration capabilities of the array are advantageously utilized. A sparsity-enforcement method that determines a subset of the available spatial modes for a parallel transmission RF coil array is employed to this end. In this manner, the utilization of the encoding power of a highly-parallel N-mode coil array in a system with only “P” available excitation channels is enabled.
摘要翻译： 提供了用于选择用于选择射频（RF））发射机到RF线圈阵列的元件的基本上最佳连接的目标依赖，稀疏执行选择的方法。 具体地，提供了一种选择发射RF线圈阵列的“N”个空间模式分布的线性组合的方法，使得有利地利用阵列的k空间轨迹和脉冲持续时间加速能力。 为此，采用了稀疏执行方法来确定并行传输RF线圈阵列的可用空间模式的子集。 以这种方式，能够在仅具有“P”可用激励信道的系统中利用高并行N模式线圈阵列的编码功率。
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3.发明授权Method for joint sparsity-enforced k-space trajectory and radiofrequency pulse design 有权联合稀疏强制k空间轨迹和射频脉冲设计方法公开(公告)号：US08154289B2
公开(公告)日：2012-04-10
申请号：US12422512
申请日：2009-04-13
IPC分类号： G01V3/00
CPC分类号： G01R33/561 , G01R33/4824 , G01R33/4836 , G01R33/5611 , G01R33/5612
摘要： A system and method is provided for simultaneously designing a radiofrequency (“RF”) pulse waveform and a magnetic field gradient waveform in a magnetic resonance imaging (“MRI”) system. The method includes determining a desired pattern of RF excitation and determining, from the desired pattern of RF excitation, a plurality of k-space locations indicative of the magnetic field gradient waveform and a plurality of complex weighting factors indicative of RF energy deposited at each k-space location. The method also includes calculating, from the determined k-space locations, the magnetic field gradient waveform and calculating, from the complex weighting factors, the RF pulse waveform that will produce the desired pattern of RF excitation when produced with the calculated magnetic field gradient.
摘要翻译： 提供了一种在磁共振成像（“MRI”）系统中同时设计射频（“RF”）脉冲波形和磁场梯度波形的系统和方法。 该方法包括确定期望的RF激励模式，并根据所需的RF激励模式确定表示磁场梯度波形的多个k空间位置以及指示在每个k处沉积RF能量的多个复加权系数 - 空间位置。 该方法还包括从确定的k空间位置计算磁场梯度波形，并从复数加权因子计算当用所计算的磁场梯度产生时将产生期望的RF激励模式的RF脉冲波形。
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4.发明申请Method For Joint Sparsity-Enforced K-Space Trajectory and Radiofrequency Pulse Design 有权联合稀疏强制K空间轨迹和射频脉冲设计方法公开(公告)号：US20090256570A1
公开(公告)日：2009-10-15
申请号：US12422512
申请日：2009-04-13
IPC分类号： G01R33/32
CPC分类号： G01R33/561 , G01R33/4824 , G01R33/4836 , G01R33/5611 , G01R33/5612
摘要： A system and method is provided for simultaneously designing a radiofrequency (“RF”) pulse waveform and a magnetic field gradient waveform in a magnetic resonance imaging (“MRI”) system. The method includes determining a desired pattern of RF excitation and determining, from the desired pattern of RF excitation, a plurality of k-space locations indicative of the magnetic field gradient waveform and a plurality of complex weighting factors indicative of RF energy deposited at each k-space location. The method also includes calculating, from the determined k-space locations, the magnetic field gradient waveform and calculating, from the complex weighting factors, the RF pulse waveform that will produce the desired pattern of RF excitation when produced with the calculated magnetic field gradient.
摘要翻译： 提供了一种在磁共振成像（“MRI”）系统中同时设计射频（“RF”）脉冲波形和磁场梯度波形的系统和方法。 该方法包括确定期望的RF激励模式，并根据所需的RF激励模式确定表示磁场梯度波形的多个k空间位置以及指示在每个k处沉积RF能量的多个复加权系数 - 空间位置。 该方法还包括从确定的k空间位置计算磁场梯度波形，并从复数加权因子计算当用所计算的磁场梯度产生时将产生期望的RF激励模式的RF脉冲波形。
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5.发明授权Method for reducing maximum local specific absorption rate in magnetic resonance imaging 有权降低磁共振成像最大局部比吸收率的方法公开(公告)号：US08148985B2
公开(公告)日：2012-04-03
申请号：US12580076
申请日：2009-10-15
IPC分类号： G01V3/00
CPC分类号： G01R33/583 , G01R33/288 , G01R33/5612
摘要： A method for reducing maximum local specific absorption rate (“SAR”) in a magnetic resonance imaging (“MRI”) system is disclosed. More specifically, a plurality of candidate radio frequency (“RF”) pulses are designed and the manner in which they are applied to a subject is determined such that the maximum local SAR is substantially reduced relative to applying the candidate RF pulse that produces the lowest maximum local SAR alone. Put another way, this “time-multiplexing” of a set of RF pulses that each produce approximately the same excitation pattern yields a lower maximum local SAR than does transmitting the individual RF pulse having the lowest local SAR over many repetition times (“TRs”). A convex optimization method is utilized to determine the manner in which the RF pulses are multiplexed in time such that a substantially lower maximum local SAR is achieved.
摘要翻译： 公开了一种在磁共振成像（“MRI”）系统中降低最大局部比吸收率（“SAR”）的方法。 更具体地，设计多个候选射频（“RF”）脉冲，并且确定它们被施加到被摄体的方式，使得最大局部SAR相对于施加产生最低的候选射频脉冲而显着减小 最大的地方特区。 换句话说，每个产生大致相同的激励模式的一组RF脉冲的这种“时间复用”产生比在许多重复时间（“TR”）发送具有最低局部SAR的单个RF脉冲的最小局部SAR更低的最小局部SAR， ）。 使用凸优化方法来确定RF脉冲在时间上多路复用的方式，使得实现基本上较低的最大局部SAR。
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6.发明申请Method For Reducing Maximum Local Specific Absorption Rate In Magnetic Resonance Imaging 有权降低磁共振成像最大局部比吸收率的方法公开(公告)号：US20100134105A1
公开(公告)日：2010-06-03
申请号：US12580076
申请日：2009-10-15
IPC分类号： G01R33/48
CPC分类号： G01R33/583 , G01R33/288 , G01R33/5612
摘要： A method for reducing maximum local specific absorption rate (“SAR”) in a magnetic resonance imaging (“MRI”) system is disclosed. More specifically, a plurality of candidate radio frequency (“RF”) pulses are designed and the manner in which they are applied to a subject is determined such that the maximum local SAR is substantially reduced relative to applying the candidate RF pulse that produces the lowest maximum local SAR alone. Put another way, this “time-multiplexing” of a set of RF pulses that each produce approximately the same excitation pattern yields a lower maximum local SAR than does transmitting the individual RF pulse having the lowest local SAR over many repetition times (“TRs”). A convex optimization method is utilized to determine the manner in which the RF pulses are multiplexed in time such that a substantially lower maximum local SAR is achieved.
摘要翻译： 公开了一种在磁共振成像（“MRI”）系统中降低最大局部比吸收率（“SAR”）的方法。 更具体地，设计多个候选射频（“RF”）脉冲，并且确定它们被施加到被摄体的方式，使得最大局部SAR相对于施加产生最低的候选射频脉冲而显着减小 最大的地方特区。 换句话说，每个产生大致相同的激励模式的一组RF脉冲的这种“时间复用”产生比在许多重复时间（“TR”）发送具有最低局部SAR的单个RF脉冲的最小局部SAR更低的最小局部SAR， ）。 使用凸优化方法来确定RF脉冲在时间上多路复用的方式，使得实现基本上较低的最大局部SAR。
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公开(公告)号：US20120256626A1
公开(公告)日：2012-10-11
申请号：US13083342
申请日：2011-04-08
CPC分类号： G01R33/5612 , G01R33/288
摘要： A method of designing a parallel transmission radio frequency (RF) pulse for a magnetic resonance imaging (MRI) system includes compressing a model for a subject to be scanned by the MRI system into a plurality of voxel clusters, each voxel cluster defining a virtual observation point with a peak sensitivity to local specific absorption rate (SAR) for the voxel cluster, and defining the parallel transmission RF pulse based on an approximation of a minimization criterion having a local SAR component based on the peak sensitivity of each virtual observation point, the approximation comprising a weighted sum of the local SAR values for each virtual observation point.
摘要翻译： 设计用于磁共振成像（MRI）系统的并行传输射频（RF）脉冲的方法包括将由MRI系统扫描的对象的模型压缩成多个体素簇，每个体素簇定义虚拟观察 点对于体素簇具有对局部比吸收率（SAR）的峰值灵敏度，并且基于基于每个虚拟观测点的峰值灵敏度的具有局部SAR分量的最小化准则的近似来定义并行发射RF脉冲， 近似值包括每个虚拟观测点的局部SAR值的加权和。
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8.发明授权Method for producing spectral-spatial parallel RF excitation pulses for magnetic resonance imaging 有权用于产生用于磁共振成像的频谱 - 空间并联RF激励脉冲的方法公开(公告)号：US08085044B2
公开(公告)日：2011-12-27
申请号：US12544714
申请日：2009-08-20
申请人： Kawin Setsompop , Borjan A. Gagoski , Elfar Adalsteinsson , Vijayanand Alagappan , Lawrence L Wald
发明人： Kawin Setsompop , Borjan A. Gagoski , Elfar Adalsteinsson , Vijayanand Alagappan , Lawrence L Wald
IPC分类号： G01V3/00
CPC分类号： G01R33/583 , G01R33/246 , G01R33/4833 , G01R33/485 , G01R33/543 , G01R33/5612 , G01R33/5635 , G01R33/56509
摘要： A method for producing a spatially and spectrally selective radiofrequency (“RF”) excitation pulse includes establishing a desired spatial RF excitation pattern and establishing a desired spectral RF excitation pattern. The method also includes estimating an RF transmission profile map indicative of the transmission characteristics of an RF coil and determining, from the desired spatial and spectral excitation patterns and the estimated RF transmission profile map, at least one magnetic field gradient waveform indicative of locations in k-space to which RF energy is to be deposited. The method further includes determining, from the established spatial and spectral excitation patterns, the estimated RF transmission profile map, and the determined at least one gradient waveform, at least one RF excitation pulse waveform that will produce the desired spatial and spectral excitation patterns.
摘要翻译： 用于产生空间和频谱选择性射频（“RF”）激励脉冲的方法包括建立期望的空间RF激励模式并建立期望的频谱RF激励模式。 该方法还包括估计指示RF线圈的传输特性的RF传输分布图，并根据期望的空间和频谱激励模式以及估计的RF传输分布图确定表示k中的位置的至少一个磁场梯度波形 - 空间，RF能量将被放置到该空间。 该方法还包括根据建立的空间和频谱激励模式，确定估计的RF传输概况图和所确定的至少一个梯度波形，至少一个RF激励脉冲波形，其将产生期望的空间和频谱激励模式。
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公开(公告)号：US08653818B2
公开(公告)日：2014-02-18
申请号：US13083342
申请日：2011-04-08
IPC分类号： G01V3/00
CPC分类号： G01R33/5612 , G01R33/288
摘要： A method of designing a parallel transmission radio frequency (RF) pulse for a magnetic resonance imaging (MRI) system includes compressing a model for a subject to be scanned by the MRI system into a plurality of voxel clusters, each voxel cluster defining a virtual observation point with a peak sensitivity to local specific absorption rate (SAR) for the voxel cluster, and defining the parallel transmission RF pulse based on an approximation of a minimization criterion having a local SAR component based on the peak sensitivity of each virtual observation point, the approximation comprising a weighted sum of the local SAR values for each virtual observation point.
摘要翻译： 设计用于磁共振成像（MRI）系统的并行传输射频（RF）脉冲的方法包括将由MRI系统扫描的对象的模型压缩成多个体素簇，每个体素簇定义虚拟观察 点对于体素簇具有对局部比吸收率（SAR）的峰值灵敏度，并且基于基于每个虚拟观测点的峰值灵敏度的具有局部SAR分量的最小化准则的近似来定义并行发射RF脉冲， 近似值包括每个虚拟观测点的局部SAR值的加权和。
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10.发明授权Local SAR reduction in multi-slice pTx via SAR-hopping between excitations 有权通过激发之间的SAR跳跃，多层pTx中的局部SAR减少公开(公告)号：US09417298B2
公开(公告)日：2016-08-16
申请号：US13827700
申请日：2013-03-14
IPC分类号： G01R33/28 , G01R33/561 , G01R33/483
CPC分类号： G01R33/288 , G01R33/4835 , G01R33/5612
摘要： Described here are a system and method for designing radio frequency (“RF”) pulses for parallel transmission (“pTx”) applications, and particularly pTx applications in multislice magnetic resonance imaging (“MRI”). The concept of “SAR hopping” is implemented by framing the concept between slice-selective excitations as a constrained optimization problem that attempts designing multiple pulses simultaneously subject to an overall local SAR constraint. This results in the set of RF waveforms that yield the best excitation profiles for all pulses while ensuring that the local SAR of the average of all pulses is below the regulatory limit imposed by the FDA. Pulses are designed simultaneously while constraining local SAR, global SAR, and peak power, and average power explicitly.
摘要翻译： 这里描述了用于并行传输（“pTx”）应用的射频（“RF”）脉冲的设计，特别是在多层磁共振成像（“MRI”）中的pTx应用的系统和方法。 “跳频跳频”的概念是通过将切片选择性激励之间的概念构成一个受约束的优化问题来实现的，这个约束优化问题在总体局域SAR约束下同时尝试同时设计多个脉冲。 这产生了一组RF波形，其产生所有脉冲的最佳激励曲线，同时确保所有脉冲的平均值的局部SAR低于FDA规定的限制。 同时设计脉冲，明确地限制局部SAR，全局SAR和峰值功率，平均功率。
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