Volume conductor effects on the spatial resolution of magnetic fields and electric potentials from gastrointestinal electrical activity
Volume conductor effects on the spatial resolution of magnetic fields and electric potentials from gastrointestinal electrical activity
复制标题
DOI：
10.1007/bf02345264
复制
发表时间：
2001-01-01
影响因子：
3.2
通讯作者：
Wikswo, JP
中科院分区：
文献类型：
--
作者：
Bradshaw, LA;Richards, WO;Wikswo, JP
对胃肠电活动的磁和电检测方法的相对能力进行了分析。所采用的模型是 GEA 出现在文献中的第一个磁场体积导体模型。根据将生物电源与外部磁场和电势联系起来的空间滤波器，引入了肠道电活动产生的电势和磁场的数学模型。前向空间滤波器是空间频率的低通函数，因此更表面的外部场和电势包含比源附近的场和电势更少的空间信息。逆空间滤波器是正向滤波器的倒数，是高通函数，必须通过加窗进行正则化。由于腹部低电导率脂肪层引入的电导率不连续性，这些层外部记录的电势比磁场需要更多的正则化，因此，肠道电活动产生的磁场的空间分辨率高于外部电势的空间分辨率。在这项研究中，相距 5 厘米的两个平滑肌源在磁性上得到了充分解析，但在电学上未得到解析。因此，使用磁性测量比使用电位测量更准确地定位和成像源。
An analysis of the relative capabilities of methods for magnetic and electric detection of gastrointestinal electrical activity is presented. The model employed is the first Volume conductor model for magnetic fields from GEA to appear in the literature. A mathematical model is introduced for the electric potential and magnetic field from intestinal electrical activity in terms of the spatial filters that relate the bioelectric sources with the external magnetic fields and potentials. The forward spatial filters are low-pass functions of spatial frequency, so more superficial external fields and potentials contain less spatial information than fields and potentials near the source. Inverse spatial filters, which are reciprocals of the forward filters, are high-pass functions and must be regularised by windowing. Because of the conductivity discontinuities introduced by low-conductivity fat layers in the abdomen, the electric potentials recorded outside these layers required more regularisation than the magnetic fields, and thus, the spatial resolution of the magnetic fields from intestinal electrical activity is higher than the spatial resolution of the external potentials. In this study, two smooth muscle sources separated by 5cm were adequately resolved magnetically, but not resolved electrically Thus, sources are more accurately localized and imaged using magnetic measurements than using measurements of electric potential.