FLOW AND MOTION IMAGING BY MAGNETIC RESONANCE

在体流动和运动的测量是一种强有力的临床工具。 目前，血管造影术，包括数字减影血管造影术， 多普勒超声用于检查血管;电影血管造影术， 多门控放射性核素检查、门控X射线CT和多普勒超声是 用来评估心脏的运动 磁共振（MR）成像是 是这些技术的有吸引力的替代方案，因为它是非侵入性的， 具有良好的空间分辨率，而且，最重要的是， 对共振核的运动很敏感 质子核磁共振成像（MRI）技术将是 发展到图像运动。 运动图像是二维或三维的 一个或多个运动参数的空间图。 例如， 二维速度图像是其中每个像素的强度 反映了由其定义的体积中的运动的速度和方向， 像素和图像切片。 有待确定的具体参数是 运动类型（例如，层流或湍流）和速度、加速度，以及 加加速度（加速度的时间变化率）在平面内， 重点将放在发展快速MR 运动成像技术，因为MR图像的数据收集时间 与X射线CT相比已经很长了 将编写软件模拟，以促进对 问题，并为开发和测试提供数据， 体模和体内数据的分析软件。 流动和运动幻象 将被建造并成像以测试成像技术。 这些体模 将允许待测试的流动或运动参数的隔离。 使用体模验证技术后，将对犬进行成像。 将通过MRI评估血管和心壁运动，并验证 通过超声技术评估MR流的性能， 体内运动成像技术。 这项研究的长期目标是充分发挥 MRI对旁系血管血流和心壁运动的影响 解决方案，更详细，病人的不适感比 由当前采用的非MR技术提供。 我们的前期工作 通过软件模拟和成像幻影证实了这是一个 现实的目标。

The measurement of flow and motion in vivo is a powerful clinical tool. Currently, angiography, including digital subtraction angiography, and Doppler ultrasound are used to examine the blood vessels; cineangiography, multigated radionuclide studies, gated X-ray CT, and Doppler ultrasound are used to assess the motion of the heart. Magnetic resonance (MR) imaging is an attractive alternative to these techniques because it is non-invasive, has good spatial resolution, and, most importantly, it is inherently sensitive to the motion of resonant nuclei. Techniques of proton nuclear magnetic resonance imaging (MRI) will be developed to image motion. Motion images are two- or three-dimensional spatial maps of one or more parameters of motion. For exampole, a two-dimensional velocity image is one in which the intensity of each pixel reflects the speed and direction of motion in the volume defined by that pixel and the image slice. Specific parameters to be determined are the type of motion (e.g., laminar or turbulent) and velocity, acceleration, and jerk (the time rate of change of acceleration) both in the plane of the image and transverse to it. Emphasis will be placed on developing fast MR motion imaging techniques because the data collection time for an MR image is already long compared to X-ray CT. Software simulations will be written to foster an understanding of the problem and to provide data for the development and testing of the analytical software for phantom and in vivo data. Flow and motion phantoms will be built and imaged to test the imaging techniques. These phantoms will allow the isolation of the parameters of flow or motion to be tested. After verification of the techniques using phantoms, dogs will be imaged. Blood vessels and cardiac wall motion will be assessed by MRI and verified by ultrasound techniques to assess the performance of the MR flow and motion imaging techniques in vivo. The long-term goal of this research is to develop fully the potential of MRI to parameterize blood vessel flow and cardiac wall motion with greater resolution, in more detail, and with less discomfort to the patient than is provided by currently employed non-MR techniques. Our preliminary work with software simulations and with imaging phantoms confirms that this is a realistic goal.