多次激发扩散磁共振成像中运动伪影及偏共振伪影的联合矫正  

Joint Correction for Motion Artifacts and Off-resonance Artifacts in Multi-shot Diffusion Magnetic Resonance Imaging

作　　者：吴文川[1] 方晟[2] 郭华[1] 

机构地区：[1]清华大学生物医学工程系生物医学影像研究中心,北京100084 [2]清华大学核能与新能源技术研究院,北京100084

出　　处：《生物医学工程学杂志》2014年第3期657-661,670,共6页Journal of Biomedical Engineering

基　　金：国家自然科学基金资助项目(61271132;81101030)

摘　　要：针对多次激发扩散磁共振成像中的运动伪影和偏共振伪影,本文提出了一种联合矫正方法,可以同时去除两种伪影,而且不需要额外采集运动导航数据和主磁场不均度图。该方法使用多次激发变密度螺旋线序列采集数据,通过自动偏共振矫正算法去除模糊,运动引入的相位误差在去除模糊的过程中采用直接法或迭代法矫正。在体磁共振成像实验表明,所提出的联合矫正方法可有效去除运动伪影和偏共振效应引起的图像模糊,获得结构清晰的成像结果,且不会增加扫描时间。Aiming at motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging （ MRI）, we proposed a joint correction method in this paper to correct the two kinds of artifacts simultaneously with- out additional acquisition of navigation data and field map. We utilized the proposed method using multi-shot variable density spiral sequence to acquire MRI data and used auto-focusing technique for image deblurring. We also used di- rect method or iterative method to correct motion ihduced phase errors in the process of deblurring. In vivo MRI ex- periments demonstrated that the proposed method could effectively suppress motion artifacts and off-resonance arti- facts and achieve images with fine structures. In addition, the scan time was not increased in applying the proposed method.

关 键 词：扩散磁共振成像 变密度螺旋线序列 运动伪影矫正 去模糊 

分 类 号：R445.2[医药卫生—影像医学与核医学]