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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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公开(公告)号：US5783942A
公开(公告)日：1998-07-21
申请号：US782027
申请日：1996-12-30
IPC分类号： G01R33/563 , G01R33/565 , G01R33/20
CPC分类号： G01R33/56308 , G01R33/56545
摘要： A phase unwrapping method is provided comprising a post-processing MR operation for an array of phase-related MR data elements. The method includes the steps of defining a Region of Interest, of comparing each data element with the first and second data elements which are adjacent thereto in the array, in order to generate respectively corresponding first and second gradient values. A subset of the data elements is constructed, wherein a data element is assigned to the subset only if its corresponding first and second gradient values are less than a selected threshold value VENC/2. The data element subset is employed to generate a fitted phase function having a value at the position of each data element in the array, and the value of the fitted function thereof, for a given data element, is subtracted from the measured value thereof. A first unwrap correcting value is subtracted from the given data element if the difference is greater than a first specified level, and a second unwrap correcting value is added thereto if the difference is less than a second specified level. A measure of the number of wrapped pixels is monitored. The phase unwrap procedure can be iterated until the number of unwrapped pixels is zero, or does not decrease with further iterating.
摘要翻译： 提供了一种相位展开方法，包括用于相位相关MR数据元素阵列的后处理MR操作。 该方法包括以下步骤：定义感兴趣区域，将每个数据元素与阵列中与其相邻的第一和第二数据元素进行比较，以分别产生对应的第一和第二梯度值。 构造数据元素的子集，其中仅当其对应的第一和第二梯度值小于所选择的阈值VENC / 2时，才将数据元素分配给子集。 使用数据元素子集来产生在阵列中的每个数据元素的位置处具有值的拟合相位函数，并且从其测量值中减去给定数据元素的拟合函数的值。 如果差大于第一指定电平，则从给定数据元素中减去第一解开校正值，如果差小于第二指定电平，则将第二解开校正值加到其上。 监测包装像素数量的度量。 可以迭代相位解包过程，直到展开像素的数量为零，或者不进一步迭代减少。
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3.发明授权公开(公告)号：US10048338B2
公开(公告)日：2018-08-14
申请号：US14694621
申请日：2015-04-23
IPC分类号： G01R33/48 , G01R33/561
摘要： Systems and methods for efficiently generating MR images are provided. The method comprises acquiring k-space MR data, reconstructing an MR image from the k-space MR data, and generating the MR image. The MR image is reconstructed using an alternative-direction-method-of-multiplier (ADMM) strategy that decomposes an optimization problem into subproblems, and at least one of the subproblems is further decomposed into small problems. The further decomposition is based on Woodbury matrix identity and uses a diagonal preconditioner based on non-Toeplitz models.
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4.发明授权Method of performing magnetic resonance angiography using two-dimensional imaging and de-rated gradients 有权使用二维成像和降额梯度进行磁共振血管造影的方法公开(公告)号：US06259940B1
公开(公告)日：2001-07-10
申请号：US09301246
申请日：1999-04-28
IPC分类号： A61B5055
CPC分类号： G01R33/5635 , G01R33/56308 , G01R33/56518 , G01R33/56581
摘要： In an MRI system using high-performance gradient hardware, a method includes de-rating selected lobes in a 2DTOF imaging pulse sequence; employing images from the two-dimensional imagery to detect the presence of disease; and performing three-dimensional contrast-enhanced MRA if disease was detected at a sufficiently high level to make three-dimensional imaging useful. By de-rating selected lobes of the 2DTOF imaging pulse sequence, sensitivity to carotid stenosis at or above the clinically important range of 60-70% is achieved.
摘要翻译： 在使用高性能梯度硬件的MRI系统中，一种方法包括以2DTOF成像脉冲序列降低所选择的瓣; 使用二维图像的图像来检测疾病的存在; 并且如果在足够高的水平检测到疾病以使三维成像有用，则执行三维造影增强MRA。 通过降低2DTOF成像脉冲序列的选定的瓣膜，实现了临床上重要范围为60-70％之间的颈动脉狭窄的敏感性。
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公开(公告)号：US06201393B1
公开(公告)日：2001-03-13
申请号：US08990651
申请日：1997-12-15
IPC分类号： G01V300
CPC分类号： G01R33/56308 , G01R33/4835 , G01R33/56509
摘要： An MRI system acquires MRA data from two overlapping thin slabs using a 3DTOF pulse sequence. Motion artifacts are reduced by using a reverse centric phase encode order during the first thin slab acquisition and a centric phase encode order during the second thin slab acquisition. Patient movement is reduced by producing a uniform sound with gradient pulse sequences during the interval between thin slab acquisitions and during a preparation period prior to the first thin slab acquisition.
摘要翻译： MRI系统使用3DTOF脉冲序列从两个重叠的薄板获取MRA数据。 在第一薄板采集期间使用反向中心相位编码顺序并在第二薄板采集期间以中心相位编码顺序减少运动伪影。 通过在薄板获得之间的间隔期间和在第一薄板获取之前的准备阶段期间产生具有梯度脉冲序列的均匀声音来减少患者运动。
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公开(公告)号：US06175236B1
公开(公告)日：2001-01-16
申请号：US09047822
申请日：1998-03-25
IPC分类号： G01V300
CPC分类号： G01R33/446 , G01R33/5613
摘要： A method for acquiring spatially and spectrally selective MR images by means of an MR imaging system includes the step of selecting an SPSP pulse sequence, comprising a succession of RF sub-pulses and an oscillatory gradient magnetic field, which is disposed to select a slice through a subject. The method further includes measuring specified parameters of a perturbation magnetic field associated with the imaging system, and deriving an expression for the perturbation field from respective measured parameters and from the oscillatory gradient magnetic field. A specified ideal frequency modulation function, associated with the SPSP sequence, is disposed to offset the slice to a particular spatially localized region of the subject. The SPSP pulse sequence is modified by adjusting the frequency modulation function in specified corresponding relationship with the expression. The modified SPSP pulse sequence is then applied to the subject to excite a selected spectral species in the spatially localized region, while substantially reducing signal intensity loss resulting from the perturbation magnetic field.
摘要翻译： 用于通过MR成像系统获取空间和频谱选择性MR图像的方法包括选择包括一系列RF子脉冲和振荡梯度磁场的SPSP脉冲序列的步骤，其被设置为选择切片通过 课程。 该方法还包括测量与成像系统相关联的扰动磁场的指定参数，以及从相应的测量参数和振荡梯度磁场导出扰动场的表达式。 设置与SPSP序列相关联的指定的理想频率调制功能，以将切片偏移到对象的特定空间局部区域。 通过调整与规定的对应关系的频率调制函数来修改SPSP脉冲序列。 然后将经修改的SPSP脉冲序列应用于受试者以激发空间局部区域中的选定光谱物种，同时显着降低由扰动磁场引起的信号强度损失。
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公开(公告)号：US5435303A
公开(公告)日：1995-07-25
申请号：US263573
申请日：1994-06-23
IPC分类号： A61B5/055 , G01R33/567
CPC分类号： A61B5/0555 , G01R33/4818 , G01R33/5673
摘要： Flow encoded NMR pulse sequences are employed to acquire data sets from which a set of angiographic images can be reconstructed depicting blood flow at successive phases during the cardiac cycle. The number of angiographic images is increased by selecting views from adjacent data sets to form interpolated data sets that are employed to reconstruct angiographic images depicting blood flow at cardiac phases between the successive phases.
摘要翻译： 采用流动编码的NMR脉冲序列来获取数据集，从该数据集可以重建一组血管造影图像，描绘在心动周期期间连续相位的血流量。 通过从相邻数据集中选择视图来增加血管造影图像的数量，以形成用于重建描绘连续相之间的心脏相位的血流的血管造影图像的内插数据集。
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公开(公告)号：US5339035A
公开(公告)日：1994-08-16
申请号：US57940
申请日：1993-05-07
IPC分类号： G01R33/483 , G01R33/54 , G01R33/563 , G01R33/20
CPC分类号： G01R33/482 , G01R33/563 , G01R33/5605
摘要： An NMR scanner performs a series of pulse sequences from which NMR data is acquired and used to reconstruct an image. Image contrast is enhanced by magnetization transfer from short-T.sub.2 spin species that are saturated by an off-resonance, substantially rectangular shaped RF saturation pulse applied during each pulse sequence.
摘要翻译： NMR扫描仪执行一系列脉冲序列，从中获取NMR数据并用于重建图像。 通过在每个脉冲序列期间施加的偏共振，基本上矩形的RF饱和脉冲饱和的短T2自旋物种的磁化转移来增强图像对比度。
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9.发明申请Systems and Methods for Efficiently Generating Magnetic Resonance Images from Incomplete Data 审中-公开从不完整的数据有效地产生磁共振图像的系统和方法公开(公告)号：US20150309136A1
公开(公告)日：2015-10-29
申请号：US14694621
申请日：2015-04-23
IPC分类号： G01R33/48 , G01R33/36 , G01R33/561 , G01R33/385 , G01R33/56
CPC分类号： G01R33/4826 , G01R33/5611
摘要： Systems and methods for efficiently generating MR images are provided. The method comprises acquiring k-space MR data, reconstructing an MR image from the k-space MR data, and generating the MR image. The MR image is reconstructed using an alternative-direction-method-of-multiplier (ADMM) strategy that decomposes an optimization problem into subproblems, and at least one of the subproblems is further decomposed into small problems. The further decomposition is based on Woodbury matrix identity and uses a diagonal preconditioner based on non-Toeplitz models.
摘要翻译： 提供了有效产生MR图像的系统和方法。 该方法包括获取k空间MR数据，从k空间MR数据重建MR图像，以及生成MR图像。 使用将优化问题分解为子问题的替代方向乘法器（ADMM）策略重构MR图像，并且至少一个子问题进一步分解为小问题。 进一步分解是基于Woodbury矩阵身份，并使用基于非Toeplitz模型的对角预处理器。
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公开(公告)号：US06518759B2
公开(公告)日：2003-02-11
申请号：US09829238
申请日：2001-04-09
申请人： Matthew A. Bernstein
发明人： Matthew A. Bernstein
IPC分类号： G01V300
CPC分类号： G01R33/54
摘要： A CE-MIRA image is acquired using a centric view order. The acquired k-space data set is motion corrected by reconstructing tracking images from successive annular segments of k-space data and detecting the location of a point spread object therein. Each k-space data segment is phase corrected to align the point spread object with a reference position.
摘要翻译： 以中心视图顺序获取CE-MIRA图像。 所获取的k空间数据集通过从k空间数据的连续环形段重建跟踪图像并检测其中的点扩展对象的位置而进行运动校正。 每个k空间数据段被相位校正，以使点扩展对象与参考位置对齐。
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