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493 条记录 (耗时 0.034 秒)

    Gradient coil with correction windings and method for production thereof
    13.
    发明授权
    Gradient coil with correction windings and method for production thereof 有权

    公开(公告)号：US09658303B2

    公开(公告)日：2017-05-23

    申请号：US13771107

    申请日：2013-02-20

    申请人： Bruker BioSpin AG

    发明人： Schimun Denoth ,  Silvia Buttazzoni ,  Thomas Speck ,  Dirk Wilhelm

    IPC分类号： G01R33/385 ,  G01R33/421 ,  G01R33/565

    CPC分类号： G01R33/385 ,  G01R33/3858 ,  G01R33/4215 ,  G01R33/56518 ,  Y10T29/49004

    摘要： In a coil arrangement for nuclear magnetic resonance comprising a main coil (13), a shielding coil (14), and at least one correction coil (41), the function of which consists in forming a magnetic field gradient with eddy current properties which are as good as possible, the main coil (13) and the shielding coil (14) are electrically connected in series with the correction coil (41). The deviations of the residual field from the desired design generated by production tolerances are thereby modified by the correction coil in such a fashion that the long-lasting eddy currents are suppressed. This either reduces the waiting time that must lapse after a gradient pulse before a predetermined field homogeneity is achieved or e.g. the deviations from the desired field are minimized in imaging applications.

    Reducing artifacts in magnetic resonance images acquired using propeller echo planar imaging
    14.
    发明授权
    Reducing artifacts in magnetic resonance images acquired using propeller echo planar imaging 有权

    公开(公告)号：US09612307B2

    公开(公告)日：2017-04-04

    申请号：US14113044

    申请日：2012-04-23

    申请人： Xiaohong Joe Zhou

    发明人： Xiaohong Joe Zhou

    IPC分类号： G01R33/565 ,  G01R33/48 ,  G01R33/561

    CPC分类号： G01R33/565 ,  G01R33/4824 ,  G01R33/5616 ,  G01R33/56518 ,  G01R33/56554 ,  G01R33/56572

    摘要： In PROPELLER utilizing EPI k-space sampling, phase errors arising primarily from eddy currents can considerably degrade image quality. The phase errors include spatially constant phase errors, spatially linear phase errors, and oblique phase errors. Methods to measure and correct for these phase errors are disclosed. Two or three reference scans are acquired, each reference scan being mutually orthogonal along the orthogonal physical gradient axes in a MRI system. A spatially constant phase error and a spatially linear phase error are determined from each of the reference scans for each relevant physical gradient axis. These phase errors can be used to predict the constant, linear, and oblique phase errors in each blade of an EPI PROPELLER k-space data set. With the known phase errors for each blade, constant, linear, and/or oblique phase correction is applied prior to or during PROPELLER image reconstruction, producing an image with substantially reduced artifacts.

    Magnetic resonance imaging apparatus and vibrational error magnetic field reduction method
    17.
    发明授权
    Magnetic resonance imaging apparatus and vibrational error magnetic field reduction method 有权
    磁共振成像装置和振动误差磁场还原法

    公开(公告)号：US09453897B2

    公开(公告)日：2016-09-27

    申请号：US13817680

    申请日：2011-08-18

    申请人： Shouichi Miyawaki ,  Hiroyuki Takeuchi

    发明人： Shouichi Miyawaki ,  Hiroyuki Takeuchi

    IPC分类号： G01R33/58 ,  G01R33/389 ,  G01R33/565 ,  A61B5/055

    CPC分类号： G01R33/58 ,  A61B5/055 ,  G01R33/389 ,  G01R33/56509 ,  G01R33/56518

    摘要： Regardless of the measurement conditions, the degradation of the image quality due to a vibrational error magnetic field, which is generated by the vibration of the mechanical structure of an MRI apparatus, is reduced. In order to do so, error magnetic field image data indicating an error magnetic field distribution is acquired on the basis of an echo signal measured using a pulse sequence having a test gradient magnetic field, a parameter value of a damped vibration function showing a vibrational error magnetic field is calculated using the error magnetic field image data, and a correction magnetic field is calculated on the basis of the calculated parameter value of the damped vibration function showing the vibrational error magnetic field.

    摘要翻译： 不管测量条件如何，减少了由MRI装置的机械结构的振动产生的由振动误差磁场引起的图像质量的劣化。 为了这样做，基于使用具有测试梯度磁场的脉冲序列测量的回波信号，获得表示误差磁场分布的误差磁场图像数据，显示振动误差的阻尼振动函数的参数值 使用误差磁场图像数据计算磁场，并且基于计算出的表示振动误差磁场的阻尼振动函数的参数值来计算校正磁场。

    MAGNETIC RESONANCE IMAGING APPARATUS
    18.
    发明申请
    MAGNETIC RESONANCE IMAGING APPARATUS 审中-公开
    磁共振成像装置

    公开(公告)号：US20160245891A1

    公开(公告)日：2016-08-25

    申请号：US15047026

    申请日：2016-02-18

    申请人： KABUSHIKI KAISHA TOSHIBA ,  TOSHIBA MEDICAL SYSTEMS CORPORATION

    发明人： Masashi OOKAWA

    IPC分类号： G01R33/565 ,  G01R33/36 ,  G01R33/385

    CPC分类号： G01R33/56518 ,  G01R33/3607

    摘要： In one embodiment, an MRI apparatus includes a gradient generation circuit configured to apply a gradient pulse according to a pulse sequence in which application of an RF pulse and application of the gradient pulse are included; and an RF transmission circuit configured to (a) perform modulation on a controlled output waveform of the RF pulse in such a manner that the controlled output waveform of the RF pulse follows time variation of a magnetic resonance frequency caused by time variation of an eddy-current magnetic field estimated from a waveform of the gradient pulse and (b) apply the RF pulse subjected to the modulation to an object.

    摘要翻译： 在一个实施例中，MRI装置包括：梯度产生电路，被配置为根据应用RF脉冲和应用梯度脉冲的脉冲序列来应用梯度脉冲; 以及RF发送电路，其被配置为（a）以所述RF脉冲的受控输出波形执行调制，使得所述RF脉冲的受控输出波形遵循由涡流时间变化引起的磁共振频率的时间变化， 根据梯度脉冲的波形估计的电流磁场和（b）将经调制的RF脉冲施加到对象。

    RF shield for MRI comprising conductive coating as shielding material
    19.
    发明授权
    RF shield for MRI comprising conductive coating as shielding material 有权
    用于MRI的RF屏蔽包括作为屏蔽材料的导电涂层

    公开(公告)号：US09417301B2

    公开(公告)日：2016-08-16

    申请号：US13816512

    申请日：2011-08-19

    申请人： Cornelis Leonardus Gerardus Ham ,  Gerardus Bernardus Jozef Mulder

    发明人： Cornelis Leonardus Gerardus Ham ,  Gerardus Bernardus Jozef Mulder

    IPC分类号： G01V3/00 ,  G01R33/422 ,  C25D15/00 ,  G01R33/565

    CPC分类号： G01R33/422 ,  C25D15/00 ,  G01R33/56518

    摘要： The invention relates to a magnetic resonance imaging system (1) comprising: a main magnet (2) for generating a uniform, steady magnetic field within an examination volume, at least one RF antenna (9) for transmitting RF pulses to the examination volume for magnetic resonance spin excitation, a gradient coil unit comprising gradient coils (4, 5, 6) for generating gradient magnetic fields in the examination volume (100), an RF shield (104) disposed between said RF antenna (9) and said gradient coils (4, 5, 6), said RF shield (104) comprising a shielding material adapted for suppressing Eddy currents induced in the shield by said gradient magnetic fields and for screening RF fields towards the gradient coils (4, 5, 6), said RF fields being generated by the RF antenna (9), wherein the RF shield comprises a conductive coating (104, 110) as shielding material.

    摘要翻译： 本发明涉及一种磁共振成像系统（1），包括：用于在检查体积内产生均匀的稳定磁场的主磁体（2），用于将RF脉冲发送到检查体积的至少一个RF天线（9），用于 磁共振自旋激励，梯度线圈单元，包括用于在检查体积（100）中产生梯度磁场的梯度线圈（4,5,6）; RF屏蔽（104），设置在所述RF天线（9）和所述梯度线圈 （4,6,6），所述RF屏蔽（104）包括屏蔽材料，所述屏蔽材料适于抑制所述屏蔽体中由所述梯度磁场感应的涡流，并用于屏蔽朝向所述梯度线圈（4,5,6）的RF场，所述屏蔽材料 RF场由RF天线（9）产生，其中RF屏蔽包括作为屏蔽材料的导电涂层（104,110）。