Apparatus and method for decreasing magnetic field sensitivity of long
RF pulses
    1.
    发明授权
    Apparatus and method for decreasing magnetic field sensitivity of long RF pulses 失效
    降低长RF脉冲的磁场灵敏度的装置和方法

    公开(公告)号:US5488298A

    公开(公告)日:1996-01-30

    申请号:US351572

    申请日:1994-12-06

    IPC分类号: G01R33/48

    CPC分类号: G01R33/446

    摘要: A long RF pulse is segmented into a plurality of RF pulses segments with nuclei spin refocusing pulses provided after each RF pulse segment to maintain phase coherence off resonance and decrease nuclei spin sensitivity to magnetic field inhomogeneity. The refocusing pulses are preferably 180.degree. rectangular pulses. Magnetic gradient segments associated with the RF pulse segments have supplemental gradients at the beginning and at the end of the gradient segment to ensure that the position in k-space for the segment corresponds to the k-space position of the gradient waveform before division into segments.

    摘要翻译: 将长RF脉冲分段成具有在每个RF脉冲段之后提供的具有核自旋重聚焦脉冲的多个RF脉冲段,以保持相位相干失谐共振,并降低对磁场不均匀性的核自旋灵敏度。 重聚焦脉冲优选为180°矩形脉冲。 与RF脉冲段相关联的磁梯度段在梯度段的开始和结束处具有补充梯度,以确保该段的k空间中的位置对应于分割成段之前的梯度波形的k空间位置 。

    Method of autocalibrating parallel imaging interpolation from arbitrary K-space sampling with noise correlations weighted to reduce noise of reconstructed images
    2.
    发明授权
    Method of autocalibrating parallel imaging interpolation from arbitrary K-space sampling with noise correlations weighted to reduce noise of reconstructed images 有权
    从任意K空间采样中自动校准平行成像插值的方法,加权噪声相关,以减少重构图像的噪声

    公开(公告)号:US08638096B2

    公开(公告)日:2014-01-28

    申请号:US12907764

    申请日:2010-10-19

    IPC分类号: G01R33/56

    CPC分类号: G01R33/5611 G01R33/4824

    摘要: A computer implemented method for magnetic resonance imaging is provided. A 3D Fourier Transform acquisition is performed with two phase encode directions, wherein phase code locations are chosen so that a total number of phase encodes is less than a Nyquist rate, and closest distances between phase encode locations takes on a multiplicity of values. Readout signals are received through a multi-channel array of a plurality of receivers. An autocalibrating parallel imaging interpolation is performed and a noise correlation is generated. The noise correlation is used to weight a data consistency term of a compressed sensing iterative reconstruction. An image is created from the autocalibration parallel imaging using the weighted data consistency term. The image is displayed.

    摘要翻译: 提供了一种用于磁共振成像的计算机实现方法。 使用两个相位编码方向执行3D傅立叶变换采集,其中选择相位位置使得相位编码的总数小于奈奎斯特速率,并且相位编码位置之间的最近距离具有多个值。 通过多个接收器的多通道阵列接收读出信号。 执行自动校准并行成像内插,并产生噪声相关。 噪声相关用于加权压缩感测迭代重建的数据一致性项。 使用加权数据一致性项从自动校准并行成像创建图像。 显示图像。

    Distortion-free magnetic resonance imaging near metallic implants
    3.
    发明授权
    Distortion-free magnetic resonance imaging near metallic implants 有权
    在金属植入物附近的无畸变磁共振成像

    公开(公告)号:US07928729B2

    公开(公告)日:2011-04-19

    申请号:US12188031

    申请日:2008-08-07

    IPC分类号: G01V3/00

    摘要: A method for 3D magnetic resonance imaging (MRI) with slice-direction distortion correction is provided. One or more selective cross-sections with a thickness along a first axis is excited using a RF pulse with a bandwidth, wherein a selective cross-section is either a selective slice or selective slab. A refocusing pulse is applied to form a spin echo. One or more 2D encoded image signals are acquired with readout along a second axis and phase encoding along a third axis. Slice-direction distortion is corrected by resolving the position by resolving the frequency offset.

    摘要翻译: 提供了一种具有切片方向失真校正的3D磁共振成像(MRI)方法。 使用具有带宽的RF脉冲激发具有沿着第一轴的厚度的一个或多个选择性横截面,其中选择性截面是选择性切片或选择性板。 应用重聚焦脉冲以形成自旋回波。 一个或多个2D编码图像信号是沿第二轴读出并沿第三轴进行相位编码的。 通过解析频率偏移来解决位置来校正切片方向失真。

    DISTORTION-FREE MAGNETIC RESONANCE IMAGING NEAR METALLIC IMPLANTS
    4.
    发明申请
    DISTORTION-FREE MAGNETIC RESONANCE IMAGING NEAR METALLIC IMPLANTS 有权
    无损磁性共振成像近金属植入物

    公开(公告)号:US20100033179A1

    公开(公告)日:2010-02-11

    申请号:US12188031

    申请日:2008-08-07

    IPC分类号: G01R33/56

    摘要: A method for 3D magnetic resonance imaging (MRI) with slice-direction distortion correction is provided. One or more selective cross-sections with a thickness along a first axis is excited using a RF pulse with a bandwidth, wherein a selective cross-section is either a selective slice or selective slab. A refocusing pulse is applied to form a spin echo. One or more 2D encoded image signals are acquired with readout along a second axis and phase encoding along a third axis. Slice-direction distortion is corrected by resolving the position by resolving the frequency offset.

    摘要翻译: 提供了一种具有切片方向失真校正的3D磁共振成像(MRI)方法。 使用具有带宽的RF脉冲激发具有沿着第一轴的厚度的一个或多个选择性横截面,其中选择性截面是选择性切片或选择性板。 应用重聚焦脉冲以形成自旋回波。 一个或多个2D编码图像信号是沿第二轴读出并沿第三轴进行相位编码的。 通过解析频率偏移来解决位置来校正切片方向失真。

    RF FIELD MAPPING FOR MAGNETIC RESONANCE IMAGING
    5.
    发明申请
    RF FIELD MAPPING FOR MAGNETIC RESONANCE IMAGING 有权
    用于磁共振成像的射频场映射

    公开(公告)号:US20080150528A1

    公开(公告)日:2008-06-26

    申请号:US11614798

    申请日:2006-12-21

    IPC分类号: G01V3/14

    摘要: For in vivo magnetic resonance imaging at high field (≧3 T) it is essential to consider the homogeneity of the active B1 field (B1+), particularly if surface coils are used for RF transmission. A new method is presented for highly rapid B1+ magnitude mapping. It combines the double angle method with a B1-insensitive magnetization-reset sequence such that the choice of repetition time (TR) is independent of T1 and with a multi-slice segmented (spiral) acquisition to achieve volumetric coverage with adequate spatial resolution in a few seconds.

    摘要翻译: 对于在高场(> = 3T)下的体内磁共振成像,必须考虑活性B 1区域(B 1 + 1)的均匀性,特别是如果 表面线圈用于RF传输。 提出了一种用于高度快速的B< 1> +幅度映射的新方法。 它将双重角度方法与B 1敏感磁化复位序列相结合,使得重复时间(TR)的选择与T 1> 1不相关, 切片分段(螺旋)采集,在几秒钟内实现足够的空间分辨率的体积覆盖。

    Functional magnetic resonance imaging using steady state free precession
    7.
    发明授权
    Functional magnetic resonance imaging using steady state free precession 有权
    功能磁共振成像使用稳态自由进动

    公开(公告)号:US07096056B2

    公开(公告)日:2006-08-22

    申请号:US10463008

    申请日:2003-06-16

    IPC分类号: A61B5/05 G01V3/00

    摘要: A method for functional magnetic resonance imaging (fMRI) uses steady-state free precession (SSFP) to image changes in blood oxygenation between two time periods. A center frequency of the SSFP sequence is placed between the different resonant frequencies for oxyhemoglobin and deoxyhemoglobin whereby the signals have a phase difference of 180° and tend to cancel. By repeating the SSFP imaging sequence at different times, the difference in the measured signals provides a measure of change in oxyhemoglobin. RF flip angle of the SSFP sequence is chosen to maximize signal level in the frequency range from that of water in the presence of oxyhemoglobin and that of water in the presence of deoxyhemoglobin.

    摘要翻译: 功能磁共振成像(fMRI)的方法使用稳态自由进动(SSFP)来在两个时间段之间成像血氧饱和度变化。 SSFP序列的中心频率位于氧合血红蛋白和脱氧血红蛋白的不同谐振频率之间,由此信号具有180°的相位差并趋于抵消。 通过在不同时间重复SSFP成像序列,测量信号的差异提供氧合血红蛋白变化的量度。 选择SSFP序列的RF翻转角来使得在存在氧合血红蛋白的情况下在水的频率范围内的信号水平和在脱氧血红蛋白存在下的水的信号水平最大化。

    Algorithm for adiabatic pulse design using the Shinnar Le-Roux transform
    9.
    发明授权
    Algorithm for adiabatic pulse design using the Shinnar Le-Roux transform 有权
    使用Shinnar Le-Roux变换的绝热脉冲设计算法

    公开(公告)号:US08473536B2

    公开(公告)日:2013-06-25

    申请号:US12489285

    申请日:2009-06-22

    IPC分类号: G06F15/00 G06F7/00

    CPC分类号: G01R33/44 G01R33/4833

    摘要: A method for providing an adiabatic RF pulse that is an inversion or refocusing pulse for a RF pulse sequence is provided. A linear phase frequency profile (Flp(ω)) is determined for the adiabatic RF pulse. A quadratic phase is applied to the linear phase frequency profile for the adiabatic RF pulse to obtain F(ω), wherein the applying the quadratic phase comprises setting F(ω)=Flp(ω)eikω2. A polynomial β is set to equal a Fourier Transform (F(ω)). A corresponding minimum phase α polynomial is determined for the β polynomial. (α,β) are set as inputs to an inverse Shinnar Le-Roux transform to generate an adiabatic RF waveform. The adiabatic RF waveform is truncated to produce the adiabatic RF pulse, wherein k>0.03π/(ω5−ωp)/(N+1) and k

    摘要翻译: 提供了一种用于提供作为RF脉冲序列的反转或重聚焦脉冲的绝热RF脉冲的方法。 确定绝热RF脉冲的线性相位频率分布(Flp(ω))。 将二次相位施加到用于绝热RF脉冲的线性相位频率分布以获得F(ω),其中应用二次相位包括设置F(ω)= Flp(ω)eikomega2。 多项式β被设置为等于傅里叶变换(F(ω))。 对于β多项式确定相应的最小相位α多项式。 (α,β)被设置为反向Shinnar Le-Roux变换的输入以产生绝热RF波形。 绝热RF波形被截断以产生绝热射频脉冲,其中k> 0.03pi /(ω5-omegap)/(N + 1)和k

    Hyperpolarized dynamic chemical shift imaging with tailored multiband excitation pulses
    10.
    发明授权
    Hyperpolarized dynamic chemical shift imaging with tailored multiband excitation pulses 有权
    超极化动态化学位移成像与定制的多频激励脉冲

    公开(公告)号:US07795868B2

    公开(公告)日:2010-09-14

    申请号:US12247940

    申请日:2008-10-08

    IPC分类号: G01V3/00

    CPC分类号: G01R33/485

    摘要: A method for performing magnetic resonance spectroscopy is described. The method generally includes applying a tailored multiband spectral-spatial radio frequency excitation pulse to a sample including a first species and at least a second species having a different resonant frequency than the first species. The multiband excitation pulse excites the first species according to a first amplitude and excites the second species according to a second amplitude that is substantially greater than the first amplitude. Data is acquired from the sample. The acquired data is then utilized to generate a spectroscopic output. By way of example, the spectroscopic output is a spectroscopic image. In particular embodiments, the data for the first and second species is acquired dynamically over an observation window of time.

    摘要翻译: 描述用于执行磁共振光谱的方法。 该方法通常包括将定制的多频谱 - 空间射频激励脉冲应用于包括具有与第一种类不同的共振频率的第一物种和至少第二种类的样品。 所述多频带激励脉冲根据第一幅度激发所述第一种类,并且根据明显大于所述第一幅度的第二幅度激发所述第二种类。 从样品中获取数据。 然后利用获取的数据产生光谱输出。 作为示例,分光输出是分光图像。 在特定实施例中,在观察窗口上动态地获取第一和第二物种的数据。