Magnetic resonance imaging using demodulated k-space segments

    公开(公告)号:US20060022673A1

    公开(公告)日:2006-02-02

    申请号:US10909787

    申请日:2004-08-02

    Inventor: Albert Macovski

    Abstract: In an MRI imaging system each portion of k-space is sequentially scanned, transformed and separately demodulated. Instead of adding the k-space regions, as is the practice in the prior art, the demodulated portions are added, each representing spectral portions of the image. Each k-space portion is scanned with closely spaced lines which substantially satisfy the sampling requirement to avoid aliasing. In this way, distortion resulting from phase changes between k-space scans is avoided.

    Localized pulsed superconductive MRI system
    2.
    发明授权
    Localized pulsed superconductive MRI system 失效
    局部脉冲超导MRI系统

    公开(公告)号:US5835995A

    公开(公告)日:1998-11-10

    申请号:US738535

    申请日:1996-10-28

    CPC classification number: G01R33/445 A61N2005/1055

    Abstract: A pulsed strong magnetic field, created with a superconductive coil, is applied to a selected region of the anatomy. Following the pulse a relatively low readout field is used along with a set of spatially orthogonal gradient fields parallel to the readout field. The readout field is chosen such that the noise arises primarily from body losses, and results in negligible susceptibility effects. Following excitation, the resultant signals from the precessing moments are detected, processed and used to make magnetic resonance images of the object. The field pulsing is made efficient using energy recovery.

    Abstract translation: 用超导线圈产生的脉冲强磁场施加到解剖结构的选定区域。 在脉冲之后,使用相对低的读出场以及与读出场平行的一组空间正交梯度场。 选择读出场,使得噪声主要来自身体损失,并导致可忽略的敏感性影响。 在激励之后,检测,处理来自进动力矩的合成信号,并用于制作物体的磁共振图像。 使用能量回收使现场脉冲变得高效。

    Method of enhancing the focus of magnetic resonance images
    3.
    发明授权
    Method of enhancing the focus of magnetic resonance images 失效
    增强磁共振图像焦点的方法

    公开(公告)号:US5311132A

    公开(公告)日:1994-05-10

    申请号:US920959

    申请日:1992-07-28

    CPC classification number: G01R33/56563 G01R33/56527

    Abstract: Disclosed is a method for automatically removing blur in magnetic resonance image signals introduced due to inhomogeneity in the magnetic field and variations in magnetic susceptibility of an object being imaged. Detected signals are demodulated at several different frequencies and reconstructed to create a series of base images. The amount of blur is determined by establishing a focusing measure for each point or part in each base image, and a composite image is then constructed using only the unblurred regions from each base image. Focusing criterion can include minimization of the imaginary part of the complex MRI after removal of constant and low frequency phase information.

    Abstract translation: 公开了一种用于自动消除由于磁场不均匀性引起的磁共振图像信号中的模糊和被成像对象的磁化率的变化的方法。 检测到的信号在几个不同的频率下进行解调,并重构以产生一系列基本图像。 通过为每个基本图像中的每个点或部分建立聚焦测量来确定模糊的量,然后仅使用来自每个基本图像的未加密的区域来构造合成图像。 聚焦准则可以包括去除恒定和低频相位信息后复杂MRI的虚部的最小化。

    Bandwidth extending system for color difference signals
    4.
    发明授权
    Bandwidth extending system for color difference signals 失效
    用于色差信号的带宽扩展系统

    公开(公告)号:US5077603A

    公开(公告)日:1991-12-31

    申请号:US542063

    申请日:1990-06-22

    Inventor: Albert Macovski

    CPC classification number: H04N9/646

    Abstract: The response of color television are improved by adding a high frequency luminance component which is proportioned to the color-difference signal so as to provide color signals with correct transitions. A control function which minimizes the means square error of the luminance and color difference signals is used to weight the amplitude of the added luminance component. This control function becomes the ratio of the cross correlation of the luminance and color-difference signals to the autocorrelation of the luminance signal. In a television communications system, the control signal can be transmitted as a narrow band signal.

    Abstract translation: 通过添加与色差信号成比例的高频亮度分量来提高彩色电视机的响应,以便提供具有正确转换的彩色信号。 使用最小化亮度和色差信号的均方误差的控制功能来加权增加的亮度分量的幅度。 该控制功能成为亮度和色差信号的互相关与亮度信号的自相关的比率。 在电视通信系统中,控制信号可以作为窄带信号发送。

    Reduced noise NMR localization system
    5.
    发明授权
    Reduced noise NMR localization system 失效
    降噪NMR定位系统

    公开(公告)号:US4851777A

    公开(公告)日:1989-07-25

    申请号:US180180

    申请日:1988-04-11

    Inventor: Albert Macovski

    CPC classification number: G01R33/54 G01R33/56 G01R33/3415

    Abstract: Magnetic resonance signals are received using a plurality of coils, each sensitive to different but overlapping regions of the volume being studied. The signals are combined so as to cancel in undesired regions of the body and receive net signals from only desired parts of the volume to enhance the signal-to-noise ratio for imaging and spectroscopy.

    Abstract translation: 使用多个线圈接收磁共振信号,每个线圈对于正在研究的体积的不同但重叠的区域敏感。 信号被组合以便在身体的不期望的区域中消除,并且仅从体积的期望部分接收净信号,以增强成像和光谱学的信噪比。

    NMR imaging system using phase-shifted signals
    6.
    发明授权
    NMR imaging system using phase-shifted signals 失效
    NMR成像系统使用相移信号

    公开(公告)号:US4665366A

    公开(公告)日:1987-05-12

    申请号:US710484

    申请日:1985-03-11

    Inventor: Albert Macovski

    CPC classification number: G01R33/446

    Abstract: The nuclei in a volume are imaged using a sequence of excitations in the presence of one or more time-varying gradient fields. The resultant phase variations are cancelled to isolate a region of the volume. Various phase-modulation functions are used to provide a desired localization function. The excitation variations can be combined with time-varying gradients during the reception interval.

    Abstract translation: 在存在一个或多个时变梯度场的情况下,使用一系列激发成像体积中的细胞核。 取消所得到的相位变化以隔离体积的区域。 使用各种相位调制功能来提供期望的定位功能。 激励变化可以在接收间隔期间与时变梯度组合。

    Blood vessel projection imaging system using nuclear magnetic resonance
    7.
    发明授权
    Blood vessel projection imaging system using nuclear magnetic resonance 失效
    血管投影成像系统采用核磁共振

    公开(公告)号:US4565968A

    公开(公告)日:1986-01-21

    申请号:US466969

    申请日:1983-02-16

    Inventor: Albert Macovski

    CPC classification number: G01R33/5635 A61B5/0263 A61B5/055 G01R33/56308

    Abstract: A two-dimensional projection image of the NMR activity within a volume is obtained. The signals due to static material are cancelled and do not appear in the projection image. The signals due to moving blood in vessels produce an isolated image of the vessels with the superimposed structure removed. The excitation of a plane is accomplished using a single excitation pulse without requiring an a.c. gradient. The uniformity requirement of the inversion excitation is minimized. Images are generated which distinguish the direction of flow.

    Abstract translation: 获得体积内的NMR活性的二维投影图像。 由静电材料引起的信号被取消,不会出现在投影图像中。 由于血管中的血液移动引起的信号产生血管的隔离图像,并且重叠的结构被去除。 平面的激发是使用单个激发脉冲完成的,而不需要直流。 梯度。 反演激励的均匀性要求最小化。 生成区分流动方向的图像。

    Variable code gamma ray imaging system
    8.
    发明授权
    Variable code gamma ray imaging system 失效
    可变码伽玛射线成像系统

    公开(公告)号:US4165462A

    公开(公告)日:1979-08-21

    申请号:US794117

    申请日:1977-05-05

    CPC classification number: G01T1/295

    Abstract: A gamma-ray source distribution in the body is imaged onto a detector using an array of apertures. The transmission of each aperture is modulated using a code such that the individual views of the source through each aperture can be decoded and separated. The codes are chosen to maximize the signal to noise ratio for each source distribution. These codes determine the photon collection efficiency of the aperture array. Planar arrays are used for volumetric reconstructions and circular arrays for cross-sectional reconstructions.

    Abstract translation: 使用孔阵列将体内的伽马射线源分布成像到检测器上。 使用代码调制每个孔径的传输,使得可以对通过每个孔径的源的各个视图进行解码和分离。 选择代码以使每个源分布的信噪比最大化。 这些代码确定孔径阵列的光子收集效率。 平面阵列用于体积重建和圆形阵列用于横截面重建。

    X-ray encoding and decoding system
    9.
    发明授权
    X-ray encoding and decoding system 失效
    X射线编码和解码系统

    公开(公告)号:US3950613A

    公开(公告)日:1976-04-13

    申请号:US428453

    申请日:1973-12-26

    Inventor: Albert Macovski

    CPC classification number: G01N23/04

    Abstract: An x-ray beam is transmitted through an object under study and through an encoding grating structure consisting of alternate stripes of materials each having different x-ray absorption characteristics. The recorded image has a grating structure which is modulated by the energy spectrum information represented by the difference of the absorption characteristics of the two stripe materials. The grating amplitude information is decoded by coherent optical filtering or by scanning and used to indicate the presence of specific materials in the object.

    Magnetic resonance imaging using demodulated k-space segments
    10.
    发明授权
    Magnetic resonance imaging using demodulated k-space segments 失效
    使用解调的k空间段的磁共振成像

    公开(公告)号:US07081749B2

    公开(公告)日:2006-07-25

    申请号:US10909787

    申请日:2004-08-02

    Inventor: Albert Macovski

    Abstract: In an MRI imaging system each portion of k-space is sequentially scanned, transformed and separately demodulated. Instead of adding the k-space regions, as is the practice in the prior art, the demodulated portions are added, each representing spectral portions of the image. Each k-space portion is scanned with closely spaced lines which substantially satisfy the sampling requirement to avoid aliasing. In this way, distortion resulting from phase changes between k-space scans is avoided.

    Abstract translation: 在MRI成像系统中,k空间的每个部分被依次扫描,变换和单独解调。 与现有技术中的实践一样,代替添加k空间区域,添加解调部分,每个部分表示图像的光谱部分。 每个k空间部分以紧密间隔的线扫描,其基本上满足采样要求以避免混叠。 以这种方式,避免了由k空间扫描之间的相位变化引起的失真。

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