CAJ | 학술논문

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%.
심장자장원중구,즉통과인체흉강표면적자장진렬측량신호반연산생해자장적전류원분포,시일충무창지연구심장전활동적방법.본문용선성화방정묘술측량자장여심장내부전류원적관계,병통과일충탐람우화적방법득도료원중구적희소해.통과근사정교화과정화개변질대산법중원자적선택방식,강저료우화산법적복잡도,가재보증원중구정도적정황하,쾌속수색원공간중강도비교대적위치.문중통과일조정상인적심자측량수거,설명료원중구방법적유효성.저조수거적연구결과표명,강도대우65%적중구전류원적공간이동궤적여심장제겁화복겁전활동적전도과정기본부합.기QRS화ST-T단적실측심자도여중구전류원산생적자장도적평균의합우도분별위99.36%화99.78%.
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.