摘要
MRI领域近年来的新兴研究热点之一——磁共振介电特性成像(MR EPT)技术能通过检测射频场分布,实现活体组织介电特性断层成像。作为MR EPT技术基础之一的磁共振射频场映像(B_1 mapping)技术,其B_1场成像的质量直接影响着MR EPT算法的精度,因而准确、稳健的B_1 mapping技术对于后续的MR EPT算法至关重要。研究双角度法(DAM)和快速预饱和法(sat TFL)两种基于磁共振信号幅值的B_1 mapping技术的基本原理,以及其在体模和人体头部MR扫描中的应用,并利用FDTD仿真分析上述两种B_1 mapping技术的B_1场缩放系数(R_i)和平均相对差异系数(MRD),发现在低介电特性体模和脑白质B_1场成像中,利用FDTD仿真获得的B_1场缩放系数R_i与采用上述两种B_1 mapping技术获得的实际B_1场缩放系数R_i差异较小,它们的MRD在10%以内;然而在高介电特性体模和脑脊液B_1场成像中,采用DAM方法获得的B_1场缩放系数R_i要高于采用sat TFL方法获得的B_1场缩放系数R_i,且有DAM的MRD高达21%。研究的结果可为不同介电特性组织的B_1场成像选取合适的B_1 mapping技术提供参考,为推动MR EPT技术的实用化提供基础研究支持。
Recently developed technique of in vivo magnetic resonance electrical tomography（ MR EPT） can extract the electrical properties of human tissues by using the information of B_1 field. Thus,robust B_1 mapping technique,regarded as the base of the technique of MR EPT,is critical for MR EPT,because the quality of B_1 maps directly affects the accuracy of MR EPT. In this paper,the B_1 field scale factor（ R_i） for double angle methods（ DAM）,saturated turbo flash（ sat TFL） in the scan of the phantom and human head were calculated using the FDTD simulation,and then the performance of DAM and sat TFL was evaluated based on the mean relative difference（ MRD）. The results indicated that the difference of R_ibetween above methods was less than10% in the tissue with low dielectric properties; on the contrary,the value of R_i of DAM was higher than that of sat TFL,in the tissue with high dielectric properties such as cerebrospinal fluid,even up to 21% for DAM. The research of this study can be used to select the appropriate B_1 mapping technique for different dielectric property tissues and promote the practical application of MR EPT technology.
作者
邓官华
蓝茂英
段松
王佳佳
胡灿
辛学刚
Deng Guanhua;Lan Maoying;Duan Song;Wang Jiajia;Hu Can;Xin Xuegang(Guangdong 999 Brain Hospital, Guangzhou 510510, China;School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China;Changhai Hospital Affiliated to the Second Military Medical University, Shanghai 200433, China;South China University of Technology, Guangzhou 510006, China)
出处
《中国生物医学工程学报》
CAS
CSCD
北大核心
2018年第2期181-187,共7页
Chinese Journal of Biomedical Engineering
基金
国家重点研发计划项目(2016YFC010080)
国家自然科学基金(61671229)
广东省省级科技计划项目(2015B020214006)
关键词
磁共振
磁共振射频场映像技术
磁共振介电特性成像技术
magnetic resonance
B1 mapping techniques
magnetic resonance electrical properties tomography
作者简介
通信作者:辛学刚,E-mail:xinxg@scut.edu.cn
