MRI刚性平移运动模糊图像建模与恢复  

The Modeling and Restoration on Rigid Translational Motion Blurred Image of MRI

作　　者：陈春晓[1] 童超[1] 王世杰[2] 罗立民[2] 

机构地区：[1]南京航空航天大学生物医学工程系,南京210016 [2]东南大学生命科学与医学工程系,南京210096

出　　处：《中国生物医学工程学报》2007年第3期368-372,共5页Chinese Journal of Biomedical Engineering

基　　金：国家973计划资助(2003CB716102)。

摘　　要：磁共振成像过程中,患者的轻微运动可产生运动伪影。运动伪影会使MR图像模糊,从而影响医生对病灶区域的准确检测。传统抑制运动伪影的方法大多基于运动模型已知的情况下,忽略频率编码期间产生的运动,对K空间数据进行处理达到修正伪影的目的。本研究针对任意的刚性平移运动可由无数的匀速直线运动复合而成的特点,建立了匀速直线运动模糊图像的数学模型,并尝试在图像域内用状态空间的方法和Hough变换的理论进行处理,对小幅度水平匀速运动模糊图像的修正取得了满意的结果。在处理任意方向的匀速直线运动时,由于谱线在旋转时不可避免地进行近似插值处理,虽然校正后的图像也有较大的改善,但还有待进一步研究。另外,对较大幅度水平匀速运动模糊图像的修正,还需要寻求更好的方法来准确估计谱线中相邻暗线之间的距离。通过上述理论及实验的分析验证可以看出,本研究所提出的方法对处理MRI运动模糊图像的研究有一定的理论意义。In the process of magnetic resonance imaging （ MRI）, the motion artifacts caused by patient＇ s movement would degrade the image quality and make the detecting and locating the focus more complicated. Conventional methods of suppressing the artifacts ignore the motion produced during the process of frequency coding and correct the blurring image by dealing with the K- space data. Based on the characteristics of rigid translational motion consisting of numerous uniform motions, we established the blurring image model of uniform motion. In this work, we studied the relations between K-space and image space, attempting to correct motion artifact by the method of status-space in image space. The concept of Hough transform was also introduced to work out the motion parameter from the K-space. We obtained fine results in correcting the motion artifact caused by the uniform motion in horizontal direction. To the motion artifact of arbitrary directions, interpolation of digital image data could not be avoided when the image was rotated, even though we have obtained great improvement after correction. Further study is necessary. Furthermore, as the translational pixels increasing, more effective approach is necessary to estimate the distance between two hidden lines in frequency spectrum. The method was tested by experiments. The results show that the method is robust and effective to restore the motional blurring image in MRI.

关 键 词：磁共振成像 霍夫变换 状态空间 匀速运动 

分 类 号：R318.08[医药卫生—生物医学工程]