Fluid shear and spin-echo images.
Fluid shear and spin-echo images.
复制标题
流体剪切和自旋回波图像。
DOI：
10.1002/mrm.1910100106
复制
发表时间：
1989
影响因子：
3.3
通讯作者：
Herfkens,RJ
中科院分区：
文献类型：
--
作者：
Kuethe,DO;Herfkens,RJ
由于临床研究表明，流体中的剪切可能是磁共振图像伪影的主要原因之一，我们成像的设备，将剪切的影响，从其他运动伪影过多。该装置在两个同心圆筒之间装有流体。为了产生剪切力，我们转动外圆柱体。为了产生没有剪切的运动，我们把两个圆柱体作为一个旋转。剪切速率接近200 s−1（类似于大动脉中的剪切速率）会导致像素强度增加40%或降低到背景水平。当速度几乎平行于相位编码梯度时，可能会发生增加。当速度在频率梯度的方向上时，可以发生下降。只要体素的相位扭曲不超过2π，这种降低就类似于从“体素”内的相位色散预测的那些降低。中国科学技术出版社. Inc.
Because clinical studies have indicated that shear in fluids may be one of the major causes of magnetic resonance image artifacts, we imaged an apparatus that would separate the effects of shear from the plethora of other motion artifacts. The apparatus contained fluid between two concentric cylinders. To produce shear, we turned the outer cylinder. To produce motion without shear, we turned both cylinders as one. Shear rates near 200 s−1(similar to those in large arteries) can cause pixel intensities either to increase 40% or decrease to background levels. Increases can occur when the velocities are nearly parallel to the phase‐encoding gradient. Decreases can occur when velocities are in the direction of the frequency gradient. The decreases are similar to those predicted from phase dispersion within a “voxel” so long as the voxel's phase warp does not exceed 2π. © 1989 Academic Press. Inc.