三维多回波流动补偿定量磁化率成像(QSM)方法研究  

Three-Dimensional Multi-Echo Quantitative Susceptibility Mapping with Flow Compensation

作　　者：翁鹏飞[1] 董芳[1] 王前锋[1] 裴孟超[1] 刘田 王乙[1,3,4] 李建奇[1] 

机构地区：[1]上海市磁共振重点实验室,华东师范大学物理系,上海200062 [2]MedImageMetric,LLC,New York,USA [3]Radiology,Weill Medical College of Comell University,New York,USA [4]Biomedical Engineering,Cornell University,New York,USA

出　　处：《波谱学杂志》2015年第3期450-461,共12页Chinese Journal of Magnetic Resonance

基　　金：国家自然科学基金资助项目(81271533)

摘　　要：定量磁化率成像(QSM)利用一般成像技术舍弃的相位信息得到局部磁场变化特性,通过复杂的场到源反演计算,可直接得到定量的磁化率图,它广泛应用于测量血氧饱和度、脑部微出血、铁沉积、组织钙化等方面.然而,梯度磁场中流动会引起相位错误,并且产生显著的流动伪影,最终得到错误的QSM图像.为了矫正流动的影响,该文在3 T磁共振系统上实现了三维多回波流动补偿梯度回波序列,并用该序列采集流动水模和志愿者颅脑数据.流动水模和颅脑数据均显示,流动补偿能够明显矫正相位错误,消除流动伪影.颅脑横断位QSM结果证明,流动补偿序列可以消除血液流动引起的QSM的错误,提高QSM的准确性.Venous blood oxygen saturation, cerebral microbleeds, iron deposition and tissue calcification can be measured by quantitative susceptibility mapping （QSM） via deconvolving the magnetic resonance （MR） phase signal. However, accurate estimation of phase signal and magnitude image in QSM may be affected by flow-induced errors in the presence of field gradient, which would ultimately lead to errors in the quantitative susceptibility map reconstructed. The aim of this study is to develop a method for correcting the flow-induced errors in phase signal and magnitude image in QSM. Flow-compensated data acquisition was achieved using a three-dimensional full flow compensated multi-echo gradient echo sequence. Phantom andin vivo experiments were carried out to validate the method proposed. The results of these experiments demonstrated that flow compensation can reduce errors in the phase signal and magnitude images. Improved quantitative susceptibility map of the superior sagittal sinus vein in human brain could be obtained with the proposed method.

关 键 词：磁共振成像(MRI) 定量磁化率成像(QSM) 流动补偿 三维多回波梯度回波 流动伪影 

分 类 号：O482.53[理学—固体物理]