摘要
在中，对各种不同情况如何获取高分辨图象是一个比较复杂的技术问题，与很多参数、因素有关。本文给出了图象分辨率和图象信噪比、机器灵敏度等参数的制约关系，及在理想情况下分辨率和场梯度、采集时间窗的定量关系。针对旨在观察单细胞的ＮＭＲ显微镜成象，分析了扩散对极限分辨率的限制。针对人体定域高分辨成象介绍了几种避免图象折叠（ａｌｉａｓｉｎｇ）的方法，阐述了高分辨成象与脉冲序列的关系，并在临床１．５ＴＭＲＩ系统上分别用３ＤＦＡＳＴ序列和２ＤＳＥ序列对人手掌中指关节进行高分辨成象实验，分别得到了１ｍｍ×２００ｍ×２００ｍ和３ｍｍ×２００ｍ×２００ｍ的体分辨率。
That how to acquire high resolution image for obvious case in MRI is a complicated technical problem,because of involving many parameters and factors.This pater gives out the bound relationships between the resolution and the SNR of an image or machine and other parameters such as the numbers of average, matrix and FOV.And also the relationship between the resolution and the gradient, acquisition time under ideal case is given out.To localized in vivo high resolution imaging a few ways to avoid aliasing are introduced.In order to acquire high resolution image selecting or designing suitable pulse sequence is important.The authors use 3D FAST sequence to image the metacarpophalangeal joint in vivo on a 1.5T clinical MRI scanner,result in resolution of 1mm×200μm
出处
《CT理论与应用研究（中英文）》
1999年第1期36-43,共8页
Computerized Tomography Theory and Applications
