Dumoulin C L, Darrow R D, Eisner D R, Tarnawski M, Scott K T, Caro C G
General Electric Corporate Research and Development Center, Schenectady, New York 12301.
J Comput Assist Tomogr. 1994 Jul-Aug;18(4):652-60. doi: 10.1097/00004728-199407000-00029.
Simultaneous detection of two or more components of motion using new magnetic resonance pulse sequences was investigated.
The technique employs Fourier phase encoding to encode the first component, and phase contrast detection to encode the second. Although the technique can be generalized to any number of spatial dimensions and motional orders, applications in which one or two spatial dimensions are obtained with a single Fourier velocity or acceleration dimension are most likely to be useful. For example, Fourier-encoded velocity and phase-contrasted acceleration information can be combined into the same image.
Several variations of the pulse sequence were investigated in phantoms and human volunteers. The first variation acquired images having an appearance similar to that of Fourier velocity-encoded images in which signal displacement is proportional to velocity, but with pixel intensity determined by acceleration. In another variation two spatial dimensions were acquired with a third dimension that uses Fourier velocity encoding to measure axial velocity within a curved tube. Radial velocity components were determined simultaneously with a second velocity-encoding gradient pulse.
The phantom and in vivo results presented here suggest that simultaneous detection of two or more components of motion is feasible.
研究使用新型磁共振脉冲序列同时检测两种或更多种运动成分。
该技术采用傅里叶相位编码对第一种成分进行编码，并采用相位对比检测对第二种成分进行编码。尽管该技术可推广至任意数量的空间维度和运动阶数，但最有可能有用的应用是在单个傅里叶速度或加速度维度下获得一个或两个空间维度的情况。例如，傅里叶编码的速度信息和相位对比的加速度信息可组合在同一幅图像中。
在体模和人体志愿者中研究了脉冲序列的几种变体。第一种变体所采集图像的外观类似于傅里叶速度编码图像，其中信号位移与速度成正比，但像素强度由加速度决定。在另一种变体中，通过第三个维度采集两个空间维度，该维度使用傅里叶速度编码来测量弯曲管内的轴向速度。通过第二个速度编码梯度脉冲同时确定径向速度分量。
本文给出的体模和体内研究结果表明，同时检测两种或更多种运动成分是可行的。
