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1.发明授权Correction of artifacts caused by Maxwell terms in phase contrast angiography 失效校正由相对比血管造影术中的麦克斯韦术引起的假象
公开(公告)号：US5998996A
公开(公告)日：1999-12-07
申请号：US826183
申请日：1997-03-27
申请人： Matthew A. Bernstein , Xiaohang Zhou , Kevin F. King , Alexander Ganin , Gary H. Glover , Norbert J. Pelc , Jason A. Polzin
发明人： Matthew A. Bernstein , Xiaohang Zhou , Kevin F. King , Alexander Ganin , Gary H. Glover , Norbert J. Pelc , Jason A. Polzin
IPC分类号： G01R33/54 , A61B5/055 , G01R33/563 , G01R33/565 , G01V3/00
CPC分类号： G01R33/56581 , G01R33/56308
摘要： A method is presented for correcting Maxwell term error artifacts produced by an NMR system during the production of either a phase contrast angiogram or a complex difference angiogram. Phase corrections are made to the reconstructed phase image to eliminate the artifacts. Correction coefficients calculated from the flow encoding magnetic gradient waveforms of the phase contrast pulse sequence are used in a polynomial to calculate a set of phase error corrections. These corrections are then used to adjust the phase at each pixel of the angiogram image.
摘要翻译： 提出了一种用于在生产相位对比血管造影或复杂差异血管造影图中校正由NMR系统产生的麦克斯韦尔术语误差伪像的方法。 对重建的相位图像进行相位校正，以消除伪影。 由相位对比脉冲序列的流量编码磁梯度波形计算的校正系数用于多项式以计算一组相位误差校正。 然后使用这些校正来调整血管造影图像的每个像素处的相位。
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2.发明授权Correction for maxwell fields produced during non-rectilinear k-space sampling 失效在非直线k空间采样期间产生的maxwell场的校正
公开(公告)号：US5877629A
公开(公告)日：1999-03-02
申请号：US831546
申请日：1997-04-08
IPC分类号： G01R33/561 , G01R33/565 , G01R33/20
CPC分类号： G01R33/56554 , G01R33/4824 , G01R33/56581
摘要： Artifacts in NMR images produced by Maxwell terms during non-rectilinear scans, such as spiral scans, are reduced or eliminated. Phase corrections for in-plane and through-plane blurring are used to offset Maxwell terms errors.
摘要翻译： 减少或消除在非直线扫描（如螺旋扫描）期间由麦克斯韦尔术语产生的NMR图像中的伪像。 用于平面和平面模糊的相位校正用于抵消麦克斯韦尔术语误差。
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公开(公告)号：US06291997B1
公开(公告)日：2001-09-18
申请号：US09452440
申请日：1999-12-02
申请人： Kevin F. King , Alexander Ganin , Neville D. Gai
发明人： Kevin F. King , Alexander Ganin , Neville D. Gai
IPC分类号： G01V300
CPC分类号： G01R33/56518 , G01R33/3852
摘要： Image artifacts produced by residual magnetization in elements of the gradient field amplifier system are reduced by driving the residual magnetization to a preselected value at the end of each imaging pulse sequence. Reset gradient pulses are produced by the gradient field amplifier system after each signal is acquired to drive the residual magnetization to a selected value. A number of different reset gradient waveforms may be used, and they may be produced in a number of different ways.
摘要翻译： 通过在每个成像脉冲序列结束时将残余磁化驱动到预选值，减少梯度场放大器系统的元件中由残余磁化产生的图像伪影。 在获取每个信号之后，由梯度场放大器系统产生复位梯度脉冲以将剩余磁化驱动到所选择的值。 可以使用多个不同的复位梯度波形，并且它们可以以多种不同的方式产生。
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公开(公告)号：US06466017B1
公开(公告)日：2002-10-15
申请号：US09453274
申请日：1999-12-02
申请人： Alexander Ganin , Kevin F. King
发明人： Alexander Ganin , Kevin F. King
IPC分类号： G01V300
CPC分类号： G01R33/482
摘要： A magnetic resonance imaging system has a primary set of whole-body gradient coils and a supplemental set of gradient coils. The supplemental gradient coils are employed to produce imaging gradients when fast imaging pulse sequences are performed, and the primary set of gradient coils are employed when interleaved saturation or navigator signals pulse sequences are performed during a scan.
摘要翻译： 磁共振成像系统具有一组全身梯度线圈和一组补充梯度线圈。 当执行快速成像脉冲序列时，补充梯度线圈用于产生成像梯度，并且当在扫描期间执行交错饱和度或导航信号脉冲序列时采用梯度线圈的主要集合。
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5.发明授权公开(公告)号：US06288545B1
公开(公告)日：2001-09-11
申请号：US09274468
申请日：1999-03-22
申请人： Kevin F. King , Alexander Ganin
发明人： Kevin F. King , Alexander Ganin
IPC分类号： G01V300
CPC分类号： G01R33/58
摘要： A technique is disclosed for calibrating time delays between RF and gradient frequency pulses in a magnetic resonance imaging system. The calibration procedure includes the formation of calibration images of a phantom positioned in the gradient field system. Calibration images are processed and compared to one another to determine deviation between locations in the gradient field system and the impact of radio frequency-to-gradient waveform time delays on the deviations. Optimal time delays are identified which minimize the deviations between the calibration images. Multiple axes of the system may be calibrated through the use of symmetrical phantoms and similar pulse sequences of each axis. A spectral-spatial pulse sequence is employed bearing the calibration routine.
摘要翻译： 公开了一种用于校准磁共振成像系统中RF和梯度频率脉冲之间的时间延迟的技术。 校准过程包括形成位于梯度场系统中的体模的校准图像。 校准图像被处理并相互比较以确定梯度场系统中的位置之间的偏差以及射频到梯度波形时间延迟对偏差的影响。 识别最佳时间延迟，其最小化校准图像之间的偏差。 可以通过使用每个轴的对称体模和类似的脉冲序列校准系统的多个轴。 采用校准程序的谱空间脉冲序列。
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公开(公告)号：US06313630B1
公开(公告)日：2001-11-06
申请号：US09382905
申请日：1999-08-25
申请人： Alexander Ganin , Kevin F. King
发明人： Alexander Ganin , Kevin F. King
IPC分类号： G01U300
CPC分类号： G01R33/385 , G01R33/3852
摘要： An MRI system has two sets of gradient coils driven by two corresponding sets of gradient amplifiers. Logical gradient waveforms produced during a pulse sequence are rotated to produce corresponding physical gradient waveforms and these are distributed to drive both sets of coils simultaneously. Each distributed set of physical gradient waveforms is separately compensated for Eddy current errors, and a polarizing field Eddy current compensation signal is produced and used to modulate the RF reference frequency of the system transceiver.
摘要翻译： MRI系统具有由两组对应的梯度放大器驱动的两组梯度线圈。 在脉冲序列期间产生的逻辑梯度波形被旋转以产生相应的物理梯度波形，并且它们被分配以同时驱动两组线圈。 每个分布的物理梯度波形组分别补偿涡流电流误差，并产生偏振场涡流补偿信号，并用于调制系统收发器的RF参考频率。
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公开(公告)号：US06211675B1
公开(公告)日：2001-04-03
申请号：US09191862
申请日：1998-11-12
申请人： Alexander Ganin , Kevin F. King
发明人： Alexander Ganin , Kevin F. King
IPC分类号： G01V300
CPC分类号： G01R33/56518 , G01R33/58
摘要： An MRI system automatically performs a calibration procedure to calculate optimal compensation parameter values for all three gradient pre-emphasis filters. A single fixture is employed to measure the errors caused by gradient pulses produced by each of the three gradient systems. The measured errors are used to calculate a gradient error function and the optimal compensation parameter values are calculated for each pre-emphasis filter by finding the minimum in the gradient error function.
摘要翻译： MRI系统自动执行校准程序，以计算所有三个梯度预加重滤波器的最佳补偿参数值。 采用单个夹具来测量由三个梯度系统中的每一个产生的梯度脉冲引起的误差。 测量误差用于计算梯度误差函数，并通过求出梯度误差函数中的最小值，为每个预加重滤波器计算最优补偿参数值。
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8.发明授权Method for compensating an MRI system for time dependent gradient field distortion 失效用于补偿MRI系统的时间依赖梯度场失真的方法
公开(公告)号：US6025715A
公开(公告)日：2000-02-15
申请号：US990610
申请日：1997-12-15
申请人： Kevin F. King , Alexander Ganin
发明人： Kevin F. King , Alexander Ganin
IPC分类号： G01R33/387 , A61B5/055 , G01R33/385 , G01R33/48 , G01V3/00
CPC分类号： G01R33/385
摘要： An MRI system performs a calibration procedure to calculate optimal compensation parameter values for a pre-emphasis filter that alters the shape of gradient waveforms. The gradient field errors are measured using a series of pulse sequences in which different compensation parameter values are sampled. The measured errors are used to calculate a gradient error function and the optimal compensation parameter values are calculated by finding the minimum in the gradient error function.
摘要翻译： MRI系统执行校准程序，以计算改变梯度波形形状的预加重滤波器的最佳补偿参数值。 使用其中对不同的补偿参数值进行采样的一系列脉冲序列来测量梯度场误差。 测量误差用于计算梯度误差函数，并通过求出梯度误差函数中的最小值来计算最优补偿参数值。
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公开(公告)号：US08355551B2
公开(公告)日：2013-01-15
申请号：US12394772
申请日：2009-02-27
申请人： Kris Filip Johan Jules Thielemans , Scott David Wollenweber , Alexander Ganin , Anja Brau , Floribertus P. M. Heukensfeldt Jansen , Evren Asma , Rakesh Mullick , Ravindra Mohan Manjeshwar , Ajit Shankaranarayanan
发明人： Kris Filip Johan Jules Thielemans , Scott David Wollenweber , Alexander Ganin , Anja Brau , Floribertus P. M. Heukensfeldt Jansen , Evren Asma , Rakesh Mullick , Ravindra Mohan Manjeshwar , Ajit Shankaranarayanan
IPC分类号： G06K9/00
CPC分类号： G06T11/005 , G06T2211/412
摘要： A method and apparatus are provided for reducing motion related imaging artifacts. The method includes determining an internal motion for of two regions of the object, each region having a different level of motion, scanning the first region using a first scan protocol based on the motion, scanning a second region using a second different scan protocol based on the motion, and generating an image of the object based on the first and second regions.
摘要翻译： 提供了一种用于减少运动相关成像伪影的方法和装置。 该方法包括确定对象的两个区域的内部运动，每个区域具有不同的运动水平，基于运动使用第一扫描协议扫描第一区域，使用基于第二扫描协议的第二不同扫描协议扫描第二区域 运动，以及基于第一和第二区域生成对象的图像。
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10.发明申请公开(公告)号：US20080164875A1
公开(公告)日：2008-07-10
申请号：US11621622
申请日：2007-01-10
CPC分类号： G01R33/481 , G01R33/28 , G01T1/1603
摘要： A system and method for simultaneously acquiring PET and MR data from a subject of interest with a hybrid PET-MR scanner includes monitoring transmission times of RF and gradient coils of the MR equipment and blanking segments of the PET data stream accordingly. By excluding PET data acquired during active MR transmissions, the remaining PET data used for image reconstruction will provide improved PET image quality.
摘要翻译： 利用混合PET-MR扫描仪同时从感兴趣的对象采集PET和MR数据的系统和方法包括相应地监测MR设备的RF设备和梯形线圈的传输时间以及PET数据流的消隐段。 通过排除在有源MR传输期间获取的PET数据，用于图像重建的剩余PET数据将提供改进的PET图像质量。
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