مسئله معکوس پراکنده کاردیوگرافی مغناطیسی
Abstract
1-Introduction
2-Magnetic field in inhomogeneous medium
3-Heart-Torso Model
4-Influence of Conductivity Uncertainty on Source Reconstruction
5-Conclusions
Acknowledgement
References
Abstract
In this paper, we discuss the influence for MCG (magnetocardiography) sparse inverse problem when conductivity uncertainty exists, through a heart- torso model by boundary element method. Fixed and moving current dipoles are designed in order to study the influence of cardiac conductivity on source reconstruction. Two indicators including the position error and the reconstructed source mean distance are used to evaluate the results. The simulating results demonstrate that the index of dipole source reconstruction outside the heart is better than that inside the heart, that is, the complicated conductivity has a greater impact on source reconstruction. In addition, the position error of the source by modified FOCUSS reconstruction is close to that of the fast greedy sparse method, and sometimes better than the latter.
Introduction
In recent years, research on the heart-torso model has continued to deepen. In 1987, Jukka Sarvas derived basic equations for the biomagnetic positive and inverse problems [1]. In 1996, P Czapski studied the effects of conductivity media on the magnetic field of the heart under a real heart-torso model[2]. In 1998, G. Fischer et al. demonstrated the effectiveness of applying BEM (boundary element method) to ECG (electrocardiogram) positive and inverse problems [3]. Keller et al. studied the effect of dielectric conductivity on positive ECG problems [5]. In the same year, Mostafa Bendahmane et al. studied the excitatory propagation of the heart in isotropic media by the finite volume conductor method [6]. In 2013, Hüsnü Dal et al. proposed a FEM method for the bidomain model of cardiac electromagnetic mechanisms [7]. Xia Lin et al. of Zhejiang University in China also conducted research on constructing a precise heart-torso model [8,9].