基于贪婪稀疏方法的心脏磁场源重构  

MCG source reconstruction based on greedy sparse method

作　　者：邴璐[1] 王伟远[1] 王永良[2] 蒋式勤[1] 

机构地区：[1]同济大学电子与信息工程学院,控制科学与控制工程系,上海201804 [2]中国科学院上海微系统与信息技术研究所,上海200050

出　　处：《物理学报》2013年第11期550-558,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60771030);国家高技术研究发展计划(批准号:2008AA02Z308);上海市重点基础研究发展计划(批准号:08JC1421800);上海市重点学科建设项目(B004);信息功能材料国家重点实验室开放课题资助的课题~~

摘　　要：心脏磁场源重构,即通过人体胸腔表面的磁场阵列测量信号反演产生该磁场的电流源分布,是一种无创地研究心脏电活动的方法.本文用线性化方程描述测量磁场与心脏内部电流源的关系,并通过一种贪婪优化的方法得到了源重构的稀疏解.通过近似正交化过程和改变迭代算法中原子的选择方式,降低了优化算法的复杂度,可在保证源重构精度的情况下,快速搜索源空间中强度比较大的位置.文中通过一组正常人的心磁测量数据,说明了源重构方法的有效性.这组数据的研究结果表明,强度大于65%的重构电流源的空间移动轨迹与心脏除极和复极电活动的传导过程基本符合.其QRS和ST-T段的实测心磁图与重构电流源产生的磁场图的平均拟合优度分别为99.36%和99.78%.Current source reconstruction, i.e., reconstructing current dipole distribution through measured array signals of cardiac magnetic field on body surface, is a method for non-invasively study on the heart electrical activity. In this paper, the relationship between measured magnetic signals and current dipole distribution is described by a linear equation, and a sparse solution of current source reconstruction is achieved using a fast greedy method. This method can significantly decrease the computational complexity of or- thogonal matching pursuit （OMP） algorithm by means of approximating orthogonalisation and improving the selection vector strategy per iteration. Thereby, the sources with large dipole strength can be fast searched out with high accuracy. A set of magnetocardiogram （MCG） data of normal subject is used to demonstrate the effectiveness of this method that the trajectory of reconstructed dominant sources, whose strengths are more than 65%, is almost consistent with conduction process in depolarization and repolarization. The average goodness of fit （GOFs） of measured MCG and the magnetic field map generated by the reconstructed current sources during QRS complex and ST-T segment are 99.36% and 99.78%, respectively.

关 键 词：心磁图 逆问题 稀疏解 正交匹配追踪 

分 类 号：O441.4[理学—电磁学] TN911.7[理学—物理]