公开(公告)号：US20130038326A1

公开(公告)日：2013-02-14

申请号：US13126922

申请日：2011-04-12

申请人： Alexis Amadon ,  Martijn Cloos

发明人： Alexis Amadon ,  Martijn Cloos

IPC分类号： G01R33/48

CPC分类号： G01R33/4836 ,  G01N24/08 ,  G01R33/246 ,  G01R33/34046 ,  G01R33/44 ,  G01R33/4818 ,  G01R33/4822 ,  G01R33/4833 ,  G01R33/5659 ,  G01R33/586

摘要： A method of exciting nuclear spins in a body, the method comprising the steps of: (a) immerging said body (PB) in a static magnetic field (B0) for aligning nuclear spins along a magnetization axis (z), said static magnetic field being substantially uniform over at least a volume of interest (VOI) of said body; (b) exposing said body, or at least said volume of interest, to a time-varying magnetic field gradient having components (Gx, Gy, Gz) directed along at least three non-coplanar directions (x, y, z) and to a transverse radio-frequency field (B1), whereby said time-varying magnetic field gradient defines a three-dimensional trajectory in k-space constituted by segments linking discrete points (kT1−kT9), and said transverse radio-frequency field deposits radio-frequency energy along at least part of said trajectory for flipping said nuclear spins by a same predetermined flip angle, independently from their position within said volume of interest. A method of performing magnetic resonance imaging comprising a step of exciting nuclear spins in a body to be imaged, characterized in that said step is performed by carrying out a method. A magnetic resonance imaging scanner for carrying out such a method.

摘要翻译： 一种激发身体中的核自旋的方法，所述方法包括以下步骤：（a）将所述体（PB）浸入静磁场（B0）中，用于沿着磁化轴（z）对准核自旋，所述静磁场 在所述身体的至少一个感兴趣体积（VOI）上基本均匀; （b）使所述身体或至少所述感兴趣的体积暴露于具有沿着至少三个非共面方向（x，y，z）指向的分量（Gx，Gy，Gz）的时变磁场梯度，并且 横向射频场（B1），其中所述时变磁场梯度定义由链接离散点（kT1-kT9）和所述横向射频场存储无线电场的段构成的k空间中的三维轨迹， 沿着所述轨迹的至少一部分的频率能量，用于将所述核自旋翻转相同的预定翻转角，独立于所述感兴趣体积内的位置。 一种执行磁共振成像的方法，包括激发要成像的身体中的核自旋的步骤，其特征在于，所述步骤通过执行方法进行。 一种用于执行这种方法的磁共振成像扫描仪。

公开(公告)号：US20110037465A1

公开(公告)日：2011-02-17

申请号：US12540411

申请日：2009-08-13

申请人： Seung-Kyun Lee

发明人： Seung-Kyun Lee

IPC分类号： G01R33/44

CPC分类号： G01R33/4836 ,  G01R33/4833

摘要： A magnetic resonance imaging apparatus having a static magnetic field source, a plurality of radio frequency magnetic field sources and a plurality of gradient magnetic field sources for generating a gradient magnetic field is provided. The static magnetic field source generates a static magnetic field for aligning a spin vector of an object in a direction of the magnetic field and plurality of radio frequency magnetic field sources generate a radio frequency magnetic field for rotating the spin vector by an angle. The apparatus further includes a processor for generating a plurality of radio frequency excitation pulses for the plurality of radio frequency magnetic field sources and a plurality of gradient excitation pulses for the plurality of gradient magnetic field sources. The second half of each of the plurality of radio frequency excitation pulses comprises a time-reversed first half of a respective one of the plurality of radio frequency excitation pulses and the second half of each of the plurality of gradient excitation comprises a time-reversed and sign-reversed first half of a respective one of the plurality of gradient excitation pulses. The average value of each of the plurality of gradient excitation pulses is zero.

摘要翻译： 提供一种具有静态磁场源，多个射频磁场源和用于产生梯度磁场的多个梯度磁场源的磁共振成像装置。 静磁场源产生用于使物体在磁场方向上的自旋向量对准的静磁场，并且多个射频磁场源产生用于使旋转矢量旋转角度的射频磁场。 该装置还包括用于产生多个射频磁场源的多个射频激励脉冲和多个梯度磁场源的多个梯度激励脉冲的处理器。 多个射频激励脉冲中的每一个的后半部分包括多个射频激励脉冲中的相应一个的时间反转的前半部分，并且多个梯度激励中的每一个的后半部分包括时间反转和 符号反转多个梯度激励脉冲中的相应一个梯形激励脉冲的前半部分。 多个梯度激励脉冲的平均值为零。

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：US07385396B2

公开(公告)日：2008-06-10

申请号：US11379403

申请日：2006-04-20

申请人： Yudong Zhu

发明人： Yudong Zhu

IPC分类号： G01V3/00

CPC分类号： G01R33/583 ,  G01R33/288 ,  G01R33/3415 ,  G01R33/4833 ,  G01R33/4836 ,  G01R33/5611 ,  G01R33/5612 ,  G01R33/5659

摘要： A computer readable storage medium in an example has a computer program stored thereon and represents a set of instructions that when executed by a computer during MR imaging causes the computer to: acquire a B1 field map for each transmit coil of a parallel RF transmit coil array; determine with a computational algorithm an excitation pulse scheme for a target excitation profile based on at least one effective B1 field map for a plurality of transmit coils of the parallel RF transmit coil array; and generate at least one SAR-reduced RF pulsing sequence for a respective transmit coil of the plurality of transmit coils of the parallel RF transmit coil array. The parallel RF transmit coil array is capable of having any parallel RF transmit coil array geometry. Each effective B1 field map reflects inductive coupling effects present between a transmit coil and at least another transmit coil.

摘要翻译： 示例中的计算机可读存储介质具有存储在其上的计算机程序，并且表示一组指令，当在MR成像期间由计算机执行时，计算机执行以下操作：获取并行RF发射线圈阵列的每个发射线圈的B1场映射 ; 基于用于所述并行RF发射线圈阵列的多个发射线圈的至少一个有效B1场图，利用计算算法确定用于目标激励分布的激励脉冲方案; 并且为并联RF发射线圈阵列的多个发射线圈中的相应发射线圈产生至少一个SAR降低的RF脉冲序列。 并联RF发射线圈阵列能够具有任何并联RF发射线圈阵列几何形状。 每个有效的B1场映射反映了在发射线圈和至少另一个发射线圈之间存在的电感耦合效应。

公开(公告)号：US09891304B2

公开(公告)日：2018-02-13

申请号：US13898701

申请日：2013-05-21

申请人： Siemens Aktiengesellschaft

发明人： Josef Pfeuffer ,  Thorsten Speckner

IPC分类号： G01R33/58 ,  G01R33/483 ,  G01R33/565

CPC分类号： G01R33/583 ,  G01R33/4836 ,  G01R33/56509 ,  G01R33/56572 ,  G01R33/5659

摘要： In a method and magnetic resonance apparatus to continuously correct phase errors in a magnetic resonance measurement sequence in which multiple sequentially radiated, multidimensional, spatially-selective radio-frequency excitation pulses are used, multiple calibration gradient echoes are acquired in a calibration acquisition sequence and a correction value for a phase response and a correction value for a phase difference are calculated from the multiple calibration gradient echoes. Furthermore, an additional radio-frequency excitation pulse is radiated takes into account the correction values.

公开(公告)号：US09891303B2

公开(公告)日：2018-02-13

申请号：US13898667

申请日：2013-05-21

申请人： Siemens Aktiengesellschaft

发明人： Josef Pfeuffer ,  Thorsten Speckner

IPC分类号： G01R33/58 ,  G01R33/483 ,  G01R33/565

CPC分类号： G01R33/583 ,  G01R33/4836 ,  G01R33/56509 ,  G01R33/56572 ,  G01R33/5659

摘要： In a method and magnetic resonance system to correct phase errors in multidimensional, spatially selective radio-frequency excitation pulses in a pulse sequence used to operate the system to acquire magnetic resonance data, a multidimensional, spatially selective radio-frequency excitation pulse is radiated and multiple calibration gradient echoes are acquired. A phase correction and a time correction of the multidimensional, spatially selective radio-frequency excitation pulse is then calculated.

公开(公告)号：US09797969B2

公开(公告)日：2017-10-24

申请号：US14484576

申请日：2014-09-12

申请人： Siemens Aktiengesellschaft

发明人： Josef Pfeuffer ,  Rainer Schneider

IPC分类号： G01R33/36 ,  G01R33/48 ,  G01R33/483 ,  G01R33/56

CPC分类号： G01R33/4818 ,  G01R33/36 ,  G01R33/4833 ,  G01R33/4836 ,  G01R33/5608

摘要： In a method to generate a spatially selective excitation in an imaging region of a magnetic resonance apparatus that precedes an acquisition of magnetic resonance data, in the course of the excitation an excitation trajectory in k-space is traversed, the excitation trajectory having a symmetry relative to the k-space center in at least one direction of k-space in the sense that a first traversed extreme value in this direction corresponds to the negative of the other extreme value traversed in this direction, so the excitation trajectory is shortened in the at least one directions on one side of the zero point between the extreme values, and the shortened excitation trajectory is used for excitation.

公开(公告)号：US20150301143A1

公开(公告)日：2015-10-22

申请号：US14258376

申请日：2014-04-22

申请人： General Electric Company

发明人： Suchandrima Banerjee ,  Emine Ulku Saritas

IPC分类号： G01R33/56 ,  G01R33/38 ,  G01R33/483 ,  G01R33/34

CPC分类号： G01R33/4835 ,  G01R33/4836 ,  G01R33/561 ,  G01R33/5615 ,  G01R33/56341

摘要： A method for reduced field of view magnetic resonance (MR) imaging includes applying a pulse sequence using a plurality of gradient coils and at least one RF coil of a magnetic resonance imaging system. The pulse sequence includes a two dimensional (2D) echo-planar RF excitation pulse with a plurality of side lobes along a slice select axis and a multiband RF refocusing pulse. MR data is acquired in response to the application of the pulse sequence and at least one MR image is reconstructed based on the MR data. The at least one MR image may then be displayed.

摘要翻译： 降低视野磁共振（MR）成像的方法包括使用多个梯度线圈和磁共振成像系统的至少一个RF线圈施加脉冲序列。 脉冲序列包括具有沿片选择轴的多个旁瓣和多频带RF重聚焦脉冲的二维（2D）回波平面RF激励脉冲。 响应于脉冲序列的应用获取MR数据，并且基于MR数据重建至少一个MR图像。 然后可以显示至少一个MR图像。

公开(公告)号：US09069048B2

公开(公告)日：2015-06-30

申请号：US13141089

申请日：2009-11-23

申请人： Thomas S. Cull ,  William McLemore

发明人： Thomas S. Cull ,  William McLemore

IPC分类号： G01R33/46 ,  G01N24/08 ,  G01R33/36 ,  G01R33/483

CPC分类号： G01R33/4608 ,  G01N24/088 ,  G01R33/3614 ,  G01R33/4633 ,  G01R33/4836

摘要： A magnetic resonance apparatus includes a magnet that generates a static magnetic field, e.g., 7T, and a resonance excitation system that induces resonance in an observed nuclear species such as 13C or 31P. A decoupling delay generator introduces pauses between adjacent pulses of a decoupling pulse train configured to decouple a coupled species such as 1H. An RF amplifier whose energy shortage capacity would be exceeded by the pulse train without the pauses amplifies the pulse train with the pauses. The pauses are sufficiently short that decoupling and Nuclear Overhauser Effect enhancement are not adversely affected, but long enough to provide recovery time to the RF amplifier, e.g., 0.2 msec.

摘要翻译： 磁共振装置包括产生静态磁场（例如7T）的磁体和在观察到的核物质如13C或31P中引起共振的共振激励系统。 解耦延迟发生器在解耦脉冲串的相邻脉冲之间引入暂停，其被配置为使耦合的物质例如1H去耦。 如果没有暂停的脉冲串能够超出能量短缺的RF放大器，则会在暂停时放大脉冲串。 暂停时间足够短，使得去耦和核超越效应增强不会受到不利影响，但长度足以为RF放大器提供恢复时间，例如0.2毫秒。

公开(公告)号：US20150070011A1

公开(公告)日：2015-03-12

申请号：US14484576

申请日：2014-09-12

申请人： Siemens Aktiengesellschaft

发明人： Josef Pfeuffer ,  Rainer Schneider

IPC分类号： G01R33/48 ,  G01R33/56 ,  G01R33/483 ,  G01R33/36

CPC分类号： G01R33/4818 ,  G01R33/36 ,  G01R33/4833 ,  G01R33/4836 ,  G01R33/5608

摘要： In a method to generate a spatially selective excitation in an imaging region of a magnetic resonance apparatus that precedes an acquisition of magnetic resonance data, in the course of the excitation an excitation trajectory in k-space is traversed, the excitation trajectory having a symmetry relative to the k-space center in at least one direction of k-space in the sense that a first traversed extreme value in this direction corresponds to the negative of the other extreme value traversed in this direction, so the excitation trajectory is shortened in the at least one directions on one side of the zero point between the extreme values, and the shortened excitation trajectory is used for excitation.

摘要翻译： 在磁共振装置获取之前在磁共振装置的成像区域产生空间选择性激励的方法中，在激发过程中，遍历k空间中的激发轨迹，激励轨迹具有对称相对 在k空间的至少一个方向上到k空间中心，这意味着该方向上的第一个经过的极值对应于在该方向上穿过的另一极值的负值，因此激励轨迹在at 在极值之间的零点的一侧上的至少一个方向，并且缩短的激励轨迹用于激励。