Coil winding for quadrupolar fields
    1.
    发明授权
    Coil winding for quadrupolar fields 失效
    线圈绕组四极场

    公开(公告)号:US4310799A

    公开(公告)日:1982-01-12

    申请号:US84562

    申请日:1979-10-15

    摘要: A coil is constructed such as that required in NMR imaging apparatus and in some NMR analytical applications, gradients can be established on selected axes within a uniform magnetic field. The windings of the coil also constitute an electrostatic screen which isolates the high-frequency coupling coil from the sample. The coil comprises a pair of similar quadrupole windings uniformly interpolated on the circumference of a cylindrical surface which encloses the sample volume. The winding of each pole includes conductors lying longitudinally on the cylindrical surface and distributed symmetrically over a quadrant of the circumference, the number of conductors per radian being proportional to cos 2.theta. where .theta. is the displacement from the center of the quadrant. Adjacent pole windings belonging to different quadrupoles thus overlap and the winding density is chosen so that the outer conductors of the two windings can be interlaid to form an effectively continuous electrostatic screen. The quadrupole windings are independent and can be energized to set up the required gradients on two axes perpendicular to each other in a uniform magnetic field directed perpendicular to the cylindrical axis. A high frequency coil can be wound helically over the field gradient windings without further shielding.

    摘要翻译: 如NMR核磁共振成像设备所需的线圈构造,在一些NMR分析应用中,可以在均匀磁场内的选定轴上建立梯度。 线圈的绕组也构成将高频耦合线圈与样品隔离的静电屏幕。 线圈包括一对在包围样品体积的圆柱形表面的圆周上均匀插入的类似的四极绕组。 每个极的绕组包括纵向放置在圆柱形表面上并且对称地分布在圆周的象限上的导体,每弧度的导体数量与cos2θ成比例,其中θ是从象限中心的位移。 属于不同四极的相邻极绕组因此重叠,并且选择绕组密度,使得可以将两个绕组的外导体嵌入以形成有效连续的静电屏。 四极绕组是独立的,并且可以被激励以在垂直于圆柱轴线的均匀磁场中彼此垂直的两个轴上建立所需的梯度。 高频线圈可以螺旋地缠绕在场梯度绕组上,而不需要进一步的屏蔽。

    Methods of producing image formation from objects
    2.
    发明授权
    Methods of producing image formation from objects 失效
    从物体形成图像的方法

    公开(公告)号:US4706025A

    公开(公告)日:1987-11-10

    申请号:US879419

    申请日:1986-06-27

    摘要: To produce image information from an object it is subjected to a continuous static magnetic field along a Z axis and to sets of sequences of orthogonal gradients G.sub.x, G.sub.y and G.sub.z to the magnetic field. Spins in a selected plane (the X-Z plane) are excited by selective rf pulses and an associated G.sub.y gradient and the selected spins are subjected to all three gradients of which the G.sub.z gradient provides twist or warp to each column of spins extending along the Z axis to phase-encode the columns. The spin-echo signals are read out in the presence of a G.sub.x gradient. In each set of sequences a different value of Z gradient is employed. The Fourier transformed spin-echo signals obtained from each sequence, when arranged in order of increasing G.sub.z gradient and subjected to a second Fourier transform represent the distribution of spin density in the Z direction, thus giving a two-dimensional image of the selected X-Z plane.

    摘要翻译: 为了从物体产生图像信息,它沿着Z轴进行连续的静态磁场,并且将正交梯度Gx,Gy和Gz的序列的集合施加到磁场。 所选择的平面(XZ平面)中的自旋被选择性射频脉冲和相关联的Gy梯度激发,并且所选择的旋转经受所有三个梯度,其中Gz梯度向沿Z轴延伸的每个旋转列提供扭曲或翘曲 对列进行相位编码。 在存在Gx梯度的情况下读出自旋回波信号。 在每组序列中,采用不同的Z梯度值。 从每个序列获得的傅里叶变换的自旋回波信号,当按增加的Gz梯度并进行第二傅里叶变换的顺序排列时,表示Z方向上的自旋密度的分布,从而给出所选择的XZ平面的二维图像 。

    Methods of producing image information from objects
    3.
    发明授权
    Methods of producing image information from objects 失效
    从对象生成图像信息的方法

    公开(公告)号:US4451788A

    公开(公告)日:1984-05-29

    申请号:US320951

    申请日:1981-11-09

    摘要: To produce image information from an object it is subjected to a continuous static magnetic field along a Z axis and to sets of sequences of gradient G.sub.x, G.sub.y and G.sub.z to the magnetic field. Spins in a selected plane (the X-Z plane) are excited by selective rf pulses and an associated G.sub.y gradient and the selected spins are subjected to a reversed G.sub.y gradient together with a G.sub.x gradient. The G.sub.y gradient is then switched off and the direction of the G.sub.x gradient is then repeatedly reversed. During the action of reversal of the G.sub.x gradient a small G.sub.z gradient is provided. Each reversed G.sub.x gradient is held constant for a sufficient time for a free induction decay signal to be generated thus providing a multiple echo of the spins in the selected plane. Alternate signals are time-reversed and then both the time-reversed and non time-reversed signals are subject to Fourier transformation.

    摘要翻译: PCT No.PCT / GB81 / 00045 Sec。 371日期1981年11月9日 102(e)日期1981年11月9日PCT提交1981年3月13日PCT公布。 出版物WO81 / 02789 日期为1981年10月1日。为了从物体产生图像信息,它沿着Z轴进行连续的静态磁场以及梯度Gx,Gy和Gz的序列集合到磁场。 在选定的平面(X-Z平面)中的自旋由选择性rf脉冲和相关联的Gy梯度激发,并且所选择的旋转与Gx梯度一起经受反转的Gy梯度。 然后关闭Gy梯度,然后重复反转Gx梯度的方向。 在Gx梯度反转的作用下,提供了一个小的Gz梯度。 每个反转的Gx梯度保持恒定足够的时间以产生自由感应衰减信号,从而在所选择的平面中提供自旋的多个回波。 交替信号是时间反转的,然后时间反转信号和非时间反相信号都经过傅里叶变换。

    Methods of deriving image information from objects
    6.
    发明授权
    Methods of deriving image information from objects 失效
    从对象中导出图像信息的方法

    公开(公告)号:US4290019A

    公开(公告)日:1981-09-15

    申请号:US10913

    申请日:1979-02-09

    CPC分类号: G01R33/54

    摘要: A method of deriving image formation from an object using nuclear magnetic resonance signals comprises the steps of subjecting an object to a static magnetic field along one axis, applying a first gradient to said magnetic field which varies in a direction orthogonal to said axis together with a 90.degree. high frequency pulse, reversing the direction of said magnetic field gradient and simultaneously applying a gradient to said magnetic field which varies in a direction parallel to said one axis and then reversing the direction of said last-mentioned gradient and reading out the free induction signal from said object.

    摘要翻译: 使用核磁共振信号从对象导出图像形成的方法包括以下步骤:使物体沿着一个轴线施加静态磁场,向与所述轴线正交的方向变化的所述磁场施加第一梯度,以及 90°高频脉冲,反转所述磁场梯度的方向,同时向平行于所述一个轴的方向变化的所述磁场施加梯度,然后反转所述最后提到的梯度的方向并读出自由感应 来自所述对象的信号。

    Methods of producing images by NMR techniques
    8.
    发明授权
    Methods of producing images by NMR techniques 失效
    通过NMR技术制作图像的方法

    公开(公告)号:US4651095A

    公开(公告)日:1987-03-17

    申请号:US636857

    申请日:1984-08-01

    CPC分类号: G01R33/482

    摘要: A set of NMR free induction signals generated in nuclei in a sample are recorded in the presence of a magnetic field gradient to a static magnetic field in which the sample is positioned. Prior to recording a magnetic field gradient orthogonal to the said gradient is applied to phase-encode the signals. The individual signals of a set are differentiated by being recorded after different time integrals of the phase encoding gradient. The magnitudes of successive time integrals have a non-monotonic relationship with each other so that sufficient signal data is recorded to enable the Fourier transform operation to commence before half or less of the set of signals has been recorded. Preferably the relationship between the magnitudes of successive time integrals corresponds to a numerical sequence represented by a monotonic sequence of binary numbers re-arranged in bit-reversed order.

    摘要翻译: 在存在磁场梯度的情况下,将样品中的核中产生的一组NMR自由感应信号记录到样品所在的静态磁场。 在记录之前,将与所述梯度正交的磁场梯度应用于信号的相位编码。 通过在相位编码梯度的不同时间积分之后被记录来区分集合的各个信号。 连续时间积分的大小彼此之间具有非单调关系,从而记录足够的信号数据,以使傅里叶变换操作在已经记录了该组信号的一半以下之前开始。 优选地,连续时间积分的大小之间的关系对应于以比特反转顺序重新排列的二进制数的单调序列表示的数字序列。

    Nuclear magnetic resonance imaging method
    9.
    发明授权
    Nuclear magnetic resonance imaging method 失效
    核磁共振成像法

    公开(公告)号:US4607223A

    公开(公告)日:1986-08-19

    申请号:US520231

    申请日:1983-08-04

    CPC分类号: G01R33/4822 G01R33/5616

    摘要: A method of deriving three dimensional image information from an object using nuclear magnetic resonance signals is described. The method comprises subjecting the object to a continuous, static magnetic field and carrying out the following set of sequential steps.1. Exciting nuclear spins in a volume;2. applying non-aligned first, second and third gradients of the magnetic field;3. causing the spins to rephase periodically in the presence of the first gradient;4. phase encoding the spins in the direction of the second gradient prior to every read-out of the rephased FIS from the object;and then successively repeating the above set of steps with different values of gradient of the third gradient (G.sub.z.sup.(2)), there being a recovery interval between the repetition of successive sets of steps.

    摘要翻译: 描述了使用核磁共振信号从对象导出三维图像信息的方法。 该方法包括使物体经受连续的静态磁场并执行以下一组顺序步骤。 激动的核旋转在一个卷; 2.应用磁场的非对准的第一,第二和第三梯度; 3.在第一梯度的存在下,使自旋重新定型; 4.在从对象中读出已重定位的FIS之前,在第二梯度的方向上相位编码自旋; 然后用不同的第三梯度(Gz(2))的梯度连续地重复上述步骤,在重复连续的步骤组之间存在恢复间隔。

    Ultrasonic phased array systems
    10.
    发明授权
    Ultrasonic phased array systems 失效
    超声相控阵系统

    公开(公告)号:US4149420A

    公开(公告)日:1979-04-17

    申请号:US848522

    申请日:1977-11-04

    摘要: Ultrasonic phased array method and apparatus for the static or dynamic investigation of structures, such as organs of the body, or intra-uterine detail, wherein ultrasonic echo pulses, reflected back from a testpiece to one or a group of adjacent transducers of a linear transducer array, are converted to corresponding electric signals which are then processed to maximize the response to the echo pulses reflected from points on a predetermined axis and to minimize the response to all other echo pulses. The method is repeated using another group of transducers in the array and another predetermined axis to produce fields of video information which are focussed and then interlaced to provide an image of the testpiece at a particular instance, the method steps being repeated in rapid succession to provide a video image representative of the testpiece in real time.

    摘要翻译: 用于静态或动态调查诸如身体器官或子宫内细节的结构的超声相控阵方法和装置,其中超声回波脉冲从试片反射回线性换能器的一个或一组相邻换能器 阵列被转换成相应的电信号,然后被处理以使对从预定轴上的点反射的回波脉冲的响应最大化并且使对所有其它回波脉冲的响应最小化。 使用阵列中的另一组换能器和另一预定轴来重复该方法,以产生聚焦的视频信息的场,然后交织以在特定情况下提供试件的图像,该方法步骤被快速地连续地重复以提供 实时代表测试件的视频图像。