公开(公告)号：US09013185B2

公开(公告)日：2015-04-21

申请号：US13407852

申请日：2012-02-29

申请人： Robert W. Brown ,  Yong Wu ,  Zhen Yao ,  Shmaryu Shvarstsman ,  Thomas Chmielewski ,  Timothy Eagan

发明人： Robert W. Brown ,  Yong Wu ,  Zhen Yao ,  Shmaryu Shvarstsman ,  Thomas Chmielewski ,  Timothy Eagan

IPC分类号： G01R33/422 ,  G01R33/565

CPC分类号： G01R33/422 ,  G01R33/341 ,  G01R33/385 ,  G01R33/4822 ,  G01R33/56518 ,  Y10T83/505

摘要： Radio frequency (RF) shields used with magnetic resonance imaging (MRI) apparatus may experience gradient field induced eddy currents and RF field induced eddy currents. These eddy currents can cause the RF shield to heat up at an undesirable rate. RF shields are designed to have a desired degree of RF shielding and a desired heating attribute. Design goals for RF shields include gradient field transparency and RF field opacity, both of which can be influenced by eddy currents. Example methods identify a gradient field that will induce eddy currents and identify an RF field that will induce eddy currents. If a region on the RF shield is identified where the desired heating attribute will not be achieved, then a pattern of axial cuts and azimuthal cuts can be made in the RF shield to reduce gradient eddy current heating in the RF shield while maintaining desired RF shielding.

摘要翻译： 与磁共振成像（MRI）装置一起使用的射频（RF）屏蔽可能会经历梯度场感应涡流和射频场感应涡流。 这些涡流可以使RF屏蔽以不期望的速率加热。 RF屏蔽被设计为具有期望的RF屏蔽程度和期望的加热属性。 RF屏蔽的设计目标包括梯度场透明度和RF场不透明度，这两者都可以受涡流影响。 示例性方法识别将引起涡流的梯度场，并识别将产生涡流的RF场。 如果RF屏蔽上的区域被识别出将不能实现所需的加热属性，则可以在RF屏蔽中进行轴向切割和方位切割的图案，以减少RF屏蔽中的梯度涡流加热，同时保持所需的RF屏蔽 。

公开(公告)号：US20120229141A1

公开(公告)日：2012-09-13

申请号：US13407852

申请日：2012-02-29

申请人： Robert W. Brown ,  Yong Wu ,  Zhen Yao ,  Shmaryu Shvartsman ,  Thomas Chmielewski ,  Timothy Eagan

发明人： Robert W. Brown ,  Yong Wu ,  Zhen Yao ,  Shmaryu Shvartsman ,  Thomas Chmielewski ,  Timothy Eagan

IPC分类号： G01R33/422 ,  B26D5/00 ,  G06F17/50

CPC分类号： G01R33/422 ,  G01R33/341 ,  G01R33/385 ,  G01R33/4822 ,  G01R33/56518 ,  Y10T83/505

摘要： Radio frequency (RF) shields used with magnetic resonance imaging (MRI) apparatus may experience gradient field induced eddy currents and RF field induced eddy currents. These eddy currents can cause the RF shield to heat up at an undesirable rate. RF shields are designed to have a desired degree of RF shielding and a desired heating attribute. Design goals for RF shields include gradient field transparency and RF field opacity, both of which can be influenced by eddy currents. Example methods identify a gradient field that will induce eddy currents and identify an RF field that will induce eddy currents. If a region on the RF shield is identified where the desired heating attribute will not be achieved, then a pattern of axial cuts and azimuthal cuts can be made in the RF shield to reduce gradient eddy current heating in the RF shield while maintaining desired RF shielding.

摘要翻译： 与磁共振成像（MRI）装置一起使用的射频（RF）屏蔽可能会经历梯度场感应涡流和射频场感应涡流。 这些涡流可以使RF屏蔽以不期望的速率加热。 RF屏蔽被设计为具有期望的RF屏蔽程度和期望的加热属性。 RF屏蔽的设计目标包括梯度场透明度和RF场不透明度，这两者都可以受涡流影响。 示例性方法识别将引起涡流的梯度场，并识别将产生涡流的RF场。 如果RF屏蔽上的区域被识别出将不能实现所需的加热属性，则可以在RF屏蔽中进行轴向切割和方位切割的图案，以减少RF屏蔽中的梯度涡流加热，同时保持所需的RF屏蔽 。

公开(公告)号：US07180291B2

公开(公告)日：2007-02-20

申请号：US10536334

申请日：2003-11-25

申请人： Thomas Chmielewski ,  James A. Flock ,  Timothy Eagan

发明人： Thomas Chmielewski ,  James A. Flock ,  Timothy Eagan

IPC分类号： G01V3/00

CPC分类号： G01R33/34046

摘要： A birdcage coil (16) used in conjunction with a magnetic resonance imaging apparatus includes a first conductive loop (81, 581), a second conductive loop (82, 582), and a plurality of first conductor rungs (80, 580) disposed between the first and second conductive loops. A third conductor (83, 83″, 583) is coupled to the second conductive loop at resonance frequencies, such as by second conductor rungs (84, 84″, 584). The birdcage coil also includes switches (590) for switching the birdcage coil at least among: 1) an RF transmit mode to operate as an RF transmit coil; and 2) an RF receive mode to operate as an RF receive coil.

摘要翻译： 与磁共振成像装置结合使用的鸟笼线圈（16）包括第一导电回路（81,581），第二导电回路（82,582）和多个第一导体梯级（80,580） 第一和第二导电回路。 第三导体（83,83“，583）以共振频率，例如通过第二导体梯级（84,84”，584）耦合到第二导电回路。 鸟笼线圈还包括用于至少在以下各项之间切换鸟笼线圈的开关（590）：1）RF发射模式以用作RF发射线圈; 和2）用作RF接收线圈的射频接收模式。

公开(公告)号：US20060033497A1

公开(公告)日：2006-02-16

申请号：US10536334

申请日：2003-11-25

申请人： Thomas Chmielewski ,  James Flock ,  Timothy Eagan

发明人： Thomas Chmielewski ,  James Flock ,  Timothy Eagan

IPC分类号： G01V3/00

CPC分类号： G01R33/34046

摘要： A birdcage coil (16) used in conjunction with a magnetic resonance imaging apparatus includes a first conductive loop (81, 581), a second conductive loop (82, 582), and a plurality of first conductor rungs (80, 580) disposed between the first and second conductive loops. A third conductor (83, 83″, 583) is coupled to the second conductive loop at resonance frequencies, such as by second conductor rungs (84, 84″, 584). The birdcage coil also includes switches (590) for switching the birdcage coil at least among: 1) an RF transmit mode to operate as an RF transmit coil; and 2) an RF receive mode to operate as an RF receive coil.

摘要翻译： 与磁共振成像装置结合使用的鸟笼线圈（16）包括第一导电回路（81,581），第二导电回路（82,582）和多个第一导体梯级（80,580） 第一和第二导电回路。 第三导体（83,83“，583）以共振频率，例如通过第二导体梯级（84,84”，584）耦合到第二导电回路。 鸟笼线圈还包括用于至少在以下各项之间切换鸟笼线圈的开关（590）：1）RF发射模式以用作RF发射线圈; 和2）用作RF接收线圈的射频接收模式。

公开(公告)号：US20050046422A1

公开(公告)日：2005-03-03

申请号：US10925691

申请日：2004-08-25

申请人： William Edelstein ,  Tesfaye Kidane ,  Victor Taracilla ,  Tanvir Baig ,  Timothy Eagan ,  Robert Brown

发明人： William Edelstein ,  Tesfaye Kidane ,  Victor Taracilla ,  Tanvir Baig ,  Timothy Eagan ,  Robert Brown

IPC分类号： G01R33/385 ,  G01R33/421 ,  G01V3/00

CPC分类号： G01R33/3854 ,  G01R33/4215

摘要： The present invention provides an apparatus for reducing acoustic noise in a magnetic resonance imaging device including passive shielding located outside the actively shielded gradient winding elements in order to reduce the magnitude of fields that spread outside the gradient coil assembly in unwanted directions and interact with the magnet cryostat or other metallic magnet parts, inducing eddy currents that cause consequent acoustic noise. The passive shielding elements are conducting layers located on the outer radius of the cylindrical gradient coil assembly in a cylindrical magnet system, conducting layers located at the ends of the gradient coil assembly in a cylindrical magnet system, and conducting layers located inside the actively shielded gradient winding inner elements in a cylindrical magnet system. The passive shielding could also be located on separate structures that are vibrationally isolated from the magnet cryostat. The actively shielded gradient winding can also be extended to portions at the ends of the actively shielded gradient winding and further to portions inside the inner radius of the inner portion of the actively shielded gradient winding. The actively shielded gradient windings and passive shielding should be designed concurrently in order to substantially optimize the gradient linearity and reduce the eddy currents generated in metallic parts of the magnetic resonance imaging system.

摘要翻译： 本发明提供了一种用于降低磁共振成像装置中的声学噪声的装置，其包括位于主动屏蔽梯度绕组元件外部的无源屏蔽，以便减小在不需要的方向上扩展到梯度线圈组件外部的场的幅度并与磁体相互作用 低温恒温器或其他金属磁体部件，引起导致声音噪声的涡流。 无源屏蔽元件是位于圆柱形磁体系统中的圆柱形梯度线圈组件的外半径上的导电层，位于梯形线圈组件的端部的导电层位于圆柱形磁体系统中，导电层位于主动屏蔽梯度内 在圆柱形磁体系中缠绕内部元件。 被动屏蔽也可以位于与磁体低温恒温器振动隔离的分离结构上。 主动屏蔽的梯度绕组还可以延伸到主动屏蔽的梯度绕组的端部的部分，并且还可以延伸到主动屏蔽的梯度绕组的内部的内半径内的部分。 主动屏蔽梯度绕组和无源屏蔽应同时设计，以便基本上优化梯度线性并减少在磁共振成像系统的金属部分中产生的涡流。