Method for blood flow acceleration and velocity measurement using MR
catheters
    1.
    发明授权
    Method for blood flow acceleration and velocity measurement using MR catheters 失效
    使用MR导管进行血流加速和速度测量的方法

    公开(公告)号:US5445151A

    公开(公告)日:1995-08-29

    申请号:US264281

    申请日:1994-06-23

    摘要: A method of magnetic resonance (MR) fluid flow measurement within a subject employs an invasive device with an RF transmit/receive coil and an RF transmit coil spaced a known distance apart. The subject is positioned in a static magnetic field. The invasive device is positioned in a vessel of a subject in which fluid flow is desired to be determined. A regular pattern of RF transmission pulses are radiated through the RF transmit/receive coil causing it to cause a steady-state MR response signal. Intermittently a second RF signal is transmitted from the RF coil positioned upstream which causes a change in the steady-state MR response signal sensed by the downstream transmit/receive coil. This is detected a short delay time later at the RF receive coil. The time delay and the distance between the RF coils leads directly to a fluid velocity. By exchanging the position of the RF transmit and transmit/receive coils, retrograde velocity may be measured. In another embodiment, more RF coils are employed. The changed MR response signal may be sensed at a number of locations at different times, leading to a measured change in velocity, or acceleration of the fluid.

    摘要翻译: 在受试者内的磁共振(MR)流体流量测量的方法使用具有RF发射/接收线圈和间隔已知距离的RF发射线圈的侵入性装置。 被摄体位于静态磁场中。 将侵入性装置定位在需要确定流体流动的受试者的血管中。 通过RF发射/接收线圈辐射RF传输脉冲的规则图案,使其产生稳态MR响应信号。 间歇地从位于上游的RF线圈发送第二RF信号,引起下游发射/接收线圈感测到的稳态MR响应信号的变化。 在RF接收线圈之后检测到短时间延迟时间。 时间延迟和RF线圈之间的距离直接导致流体速度。 通过交换RF发射和发射/接收线圈的位置,可以测量逆行速度。 在另一个实施例中,采用更多的RF线圈。 可以在不同时间的多个位置处感测改变的MR响应信号,导致测量的流体变化或流体的加速度。

    Apparatus and methods for magnetic resonance (MR) angiography using
fluids polarized at low temperatures
    2.
    发明授权
    Apparatus and methods for magnetic resonance (MR) angiography using fluids polarized at low temperatures 失效
    使用在低温下极化的流体进行磁共振(MR)血管造影术的装置和方法

    公开(公告)号:US5626137A

    公开(公告)日:1997-05-06

    申请号:US537572

    申请日:1995-10-02

    IPC分类号: A61B5/055

    CPC分类号: A61B5/055

    摘要: A magnetic resonance (MR) active invasive device system employs a small, high-field polarizing magnet, and a large, possibly low-field magnetic resonance (MR) imaging magnet for the purpose of generating MR angiograms of selected blood vessels. A subject is positioned in a large MR imaging magnet. A catheter is inserted into the patient at or near the root of a vessel tree to be imaged. A fluid, intended to be used as a contrast agent is first cooled and frozen, and then passed through the small high-field polarizing magnet where it becomes highly polarized. The frozen fluid is then heated and melted to physiologic temperatures and introduced into the subject through the catheter. Radiofrequency (RF) pulses and magnetic field gradients are then applied to the patient as in conventional MR imaging. Since the fluid has a larger longitudinal magnetization than tissue which has not passed through the polarizing magnet, the fluid produces a much larger MR response signal than other tissue, resulting in vessel tree images with excellent contrast.

    摘要翻译: 磁共振(MR)主动侵入性装置系统采用小型,高场极化磁体和大型可能的低场磁共振(MR)成像磁体,用于产生选定血管的MR血管造影。 受试者位于大型MR成像磁体中。 在要成像的血管树的根部处或附近将导管插入患者体内。 首先将要用作造影剂的流体冷却并冷冻,然后通过小型高场极化磁体,在其中高度极化。 然后将冷冻的流体加热并熔化成生理温度并通过导管引入受试者。 然后将射频(RF)脉冲和磁场梯度应用于患者,如在常规MR成像中。 由于流体具有比没有通过偏振磁体的组织更大的纵向磁化强度,所以流体产生比其他组织大得多的MR响应信号,导致具有优异对比度的容器树图像。

    Imaging of interventional devices during medical procedures
    3.
    发明授权
    Imaging of interventional devices during medical procedures 失效
    在医疗过程中形成介入装置

    公开(公告)号:US5577502A

    公开(公告)日:1996-11-26

    申请号:US415409

    申请日:1995-04-03

    摘要: A tracking system monitors the position of a device within a subject and superimposes a graphic symbol on a diagnostic image of the subject. Registration of the tracked location with the diagnostic image is maintained in the presence of subject motion by monitoring subject motion and adjusting the display to compensate for subject motion. Motion monitoring can be performed with ultrasonic, optical or mechanical methods. The display can be adjusted by modifying the displayed location of the device or it can be adjusted by translating, rotating or distorting the diagnostic image.

    摘要翻译: 跟踪系统监视对象内的设备的位置并将图形符号叠加在被摄体的诊断图像上。 通过监视对象运动并调整显示以补偿被摄体运动,通过诊断图像对被跟踪位置的注册保持在受试者运动的存在下。 运动监测可以用超声波,光学或机械方法进行。 可以通过修改显示的设备位置来调整显示,也可以通过翻译,旋转或扭曲诊断图像进行调整。

    Magnetic resonance (MR) angiography in a low-field imaging magnet
    4.
    发明授权
    Magnetic resonance (MR) angiography in a low-field imaging magnet 失效
    低场成像磁体中的磁共振(MR)血管造影

    公开(公告)号:US5479925A

    公开(公告)日:1996-01-02

    申请号:US264283

    申请日:1994-06-23

    摘要: A magnetic resonance (MR) active invasive device system employs a small, high-field polarizing magnet, and a large low-field magnetic resonance (MR) imaging magnet for the purpose of generating MR angiograms of selected blood vessels. A subject is positioned in a large low-field MR imaging magnet. A catheter in inserted into the patient at or near the root of a vessel tree desired to be imaged. A fluid, intended to be used as a contrast agent is first passed through the small high-field polarizing magnet, causing a great deal of net longitudinal magnetization to be produced in the fluid. The fluid is then introduced into the subject through the catheter. Radiofrequency (RF) pulses and magnetic field gradients are then applied to the patient as in conventional MR imaging. Since the fluid has a larger longitudinal magnetization, before the MR imaging sequence, the fluid produces a much larger MR response signal than other tissue resulting in the vessel tree being imaged with excellent contrast.

    摘要翻译: 磁共振(MR)主动侵入性装置系统采用小型,高场极化磁体和大型低场磁共振(MR)成像磁体,用于产生选定血管的MR血管造影。 受试者位于大型低场MR成像磁体中。 插入患者的导管,该导管需要被成像的血管树根部或附近。 旨在用作造影剂的流体首先​​通过小型高场极化磁体,导致在流体中产生大量的净纵向磁化强度。 然后通过导管将流体引入受试者。 然后将射频(RF)脉冲和磁场梯度应用于患者,如在常规MR成像中。 由于流体具有较大的纵向磁化强度,在MR成像序列之前,流体产生比其它组织大得多的MR响应信号,导致血管树被成像,具有出色的对比度。

    Invasive system employing a radiofrequency tracking system
    5.
    发明授权
    Invasive system employing a radiofrequency tracking system 失效
    入射系统采用射频跟踪系统

    公开(公告)号:US5445150A

    公开(公告)日:1995-08-29

    申请号:US10720

    申请日:1993-01-29

    IPC分类号: A61B5/06 G01V3/12 A61B5/00

    摘要: An invasive imaging system employs a self-contained RF transmitter attached to an invasive device which allows tracking of the invasive device within a subject without physical connections to a tracking/display system and without the use of ionizing rays. An imaging system obtains a medical diagnostic image of the subject. The self-contained RF transmitter is comprised of a power generator, a power conversion means such as an oscillator which converts the generated power to a radiofrequency (RF) signal, and a broadcasting means such as a tuned transmit coil for radiating the RF signal. The radiated RF signal is received by receive coils of a tracking/display means which calculates the location of the RF transmitter. The tracking/display means displays the medical diagnostic image on a monitor and superimposes a symbol on the image at a position corresponding to the calculated location of the RF transmitter. Prior to operation, the power generator may be energized inductively, photo-voltaically, or by direct contact with either an external power supply. The power generator may also be a charged battery sealed inside the RF transmitter. The RF transmitter may be implanted to track the motion of internal tissues.

    摘要翻译: 侵入式成像系统采用连接到侵入性装置的独立的RF发射器,其允许跟踪受试者内的侵入性装置,而无需与跟踪/显示系统的物理连接,而不使用电离射线。 成像系统获得被检体的医学诊断图像。 独立的射频发射机包括功率发生器,诸如将所产生的功率转换为射频(RF)信号的振荡器的功率转换装置,以及用于辐射RF信号的诸如调谐发射线圈的广播装置。 辐射的RF信号由计算RF发射机的位置的跟踪/显示装置的接收线圈接收。 跟踪/显示装置在监视器上显示医疗诊断图像,并且在与RF计算机的位置相对应的位置处将图像叠加在图像上。 在操作之前,发电机可以感应地,光电地或通过与外部电源直接接触而被激励。 发电机也可以是密封在RF发射器内的充电电池。 可以植入RF发射器以跟踪内部组织的运动。

    Tracking system to monitor the position and orientation of a device
using magnetic resonance detection of a sample contained within the
device
    6.
    发明授权
    Tracking system to monitor the position and orientation of a device using magnetic resonance detection of a sample contained within the device 失效
    跟踪系统用于使用包含在该装置内的样本的磁共振检测来监测装置的位置和方位

    公开(公告)号:US5271400A

    公开(公告)日:1993-12-21

    申请号:US861662

    申请日:1992-04-01

    摘要: A tracking system employs magnetic resonance signals to monitor the position and orientation of a device, such as a catheter, within a subject. The device has an MR active sample and a receiver coil which is sensitive to magnetic resonance signals generated by the MR active sample. These signals are detected in the presence of magnetic field gradients and thus have frequencies which are substantially proportional to the location of the coil along the direction of the applied gradient. Signals are detected responsive to sequentially applied mutually orthogonal magnetic gradients to determine the device's position in several dimensions. The position of the device as determined by the tracking system is superimposed upon independently acquired medical diagnostic images. One or more devices can be simultaneously tracked.

    摘要翻译: 跟踪系统采用磁共振信号来监测被检体内的装置(例如导管)的位置和方位。 该器件具有对MR活性样品产生的磁共振信号敏感的MR活性样品和接收器线圈。 在存在磁场梯度的情况下检测这些信号,因此具有与沿施加的梯度方向的线圈位置基本成比例的频率。 响应于顺序施加的相互正交的磁梯度来检测信号以确定器件在几个维度中的位置。 由跟踪系统确定的设备的位置叠加在独立获取的医学诊断图像上。 可以同时跟踪一个或多个设备。

    Apparatus and methods for magnetic resonance (MR) imaging of cavities
using fluids polarized at low temperatures
    8.
    发明授权
    Apparatus and methods for magnetic resonance (MR) imaging of cavities using fluids polarized at low temperatures 失效
    使用在低温下极化的流体对空腔进行磁共振(MR)成像的装置和方法

    公开(公告)号:US5617859A

    公开(公告)日:1997-04-08

    申请号:US537574

    申请日:1995-10-02

    IPC分类号: A61B5/055

    CPC分类号: A61B5/055

    摘要: A magnetic resonance (MR) active invasive device system employs a small, high-field polarizing magnet, and a large magnetic resonance (MR) imaging magnet for the purpose of generating MR images of selected body cavities. A subject is positioned in a large low-field MR imaging magnet. A substance, intended to be used as a contrast agent is first cooled, and then passed through the small high-field polarizing magnet where it becomes highly polarized. The substance is then heated to physiologic temperatures, vaporized, and introduced into the subject through a transfer conduit as a vapor. Radiofrequency (RF) pulses and magnetic field gradients are then applied to the patient as in conventional MR imaging. Since the vapor is highly polarized, it can be imaged even though it has a much lower density than the surrounding tissue.

    摘要翻译: 磁共振(MR)有源侵入性装置系统采用小型高场极化磁体和大型磁共振(MR)成像磁体,用于产生选定体腔的MR图像。 受试者位于大型低场MR成像磁体中。 首先将要用作造影剂的物质冷却,然后通过小型高场极化磁体,在其中高度极化。 然后将物质加热至生理温度,蒸发,并通过作为蒸气的转移导管引入受试者。 然后将射频(RF)脉冲和磁场梯度应用于患者,如在常规MR成像中。 由于蒸气是高度极化的,所以即使其具有比周围组织低得多的密度,也可以成像。

    Tracking system to monitor the position of a device using multiplexed
magnetic resonance detection
    10.
    发明授权
    Tracking system to monitor the position of a device using multiplexed magnetic resonance detection 失效
    跟踪系统监视使用复用磁共振检测的设备的位置

    公开(公告)号:US5353795A

    公开(公告)日:1994-10-11

    申请号:US989283

    申请日:1992-12-10

    摘要: A tracking system employs magnetic resonance signals to monitor the position of a device such as a catheter within a subject. The device has a receiver coil which is sensitive to magnetic resonance signals generated in the subject. These signals are detected in the presence of magnetic field gradients and thus have frequencies which are substantially proportional to the location of the coil along the direction of the applied gradient. Signals are detected responsive to applied magnetic gradients to determine the position of the device in several dimensions. Sensitivity of the measured position to resonance offset conditions such as transmitter frequency misadjustment, chemical shift and the like is minimized by repeating the process a plurality of times with selected amplitudes and polarities for the applied magnetic field gradient. Linear combinations of the data acquired responsive to the different applied magnetic field gradients are computed to determine the position of the device in three orthogonal dimensions. The position of the device as determined by the tracking system is superimposed upon independently acquired medical diagnostic images.

    摘要翻译: 跟踪系统采用磁共振信号来监测被检体内诸如导管之类的装置的位置。 该装置具有对受试者中产生的磁共振信号敏感的接收器线圈。 在存在磁场梯度的情况下检测这些信号,因此具有与沿施加的梯度方向的线圈位置基本成比例的频率。 响应于所施加的磁梯度检测信号以确定装置在几个维度中的位置。 通过用所施加的磁场梯度的选定幅度和极性重复该过程多次来最小化测量位置对谐振偏移条件(例如发射机频率误调整,化学位移等)的灵敏度。 计算响应于不同施加的磁场梯度采集的数据的线性组合,以确定装置在三个正交尺寸中的位置。 由跟踪系统确定的设备的位置叠加在独立获取的医学诊断图像上。