Modeling Magnetomyograms of Uterine Contractions during Pregnancy Using a Multiscale Forward Electromagnetic Approach.
Modeling Magnetomyograms of Uterine Contractions during Pregnancy Using a Multiscale Forward Electromagnetic Approach.
复制标题
DOI：
10.1371/journal.pone.0152421
复制
发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Nehorai A
中科院分区：
文献类型：
--
作者：
Zhang M;Tidwell V;La Rosa PS;Wilson JD;Eswaran H;Nehorai A
了解怀孕期间子宫收缩的机制对于预测分娩的开始和早产尤为重要。早产可能导致新生儿严重的健康问题，以及对社会造成巨大的经济负担。已经开发了各种技术，如肌电图（EMG）和磁肌描记术（MMG），以量化子宫收缩。然而，没有广泛接受的方法来预测分娩的基础上电磁测量是可用的。因此，开发EMG和MMG的生物物理模型可以帮助更好地理解子宫收缩，解释真实的测量结果，并检测分娩。在这项工作中，我们提出了一个多尺度的现实模型在怀孕期间的子宫收缩。在细胞水平上，建立在分叉理论，我们应用广义FitzHugh-Nagumo（FHN）方程，产生高原型和爆发型动作电位。在组织水平上，我们引入了一个随机纤维取向模型适用于任意子宫形状。我们还开发了跨膜电位的传播速度的解析表达式。在器官水平，基于孕妇的磁共振图像提供真实的体积导体几何形状模型。为了模拟SQUID阵列生殖评估（SARA）设备的测量，我们提出了一个传感器阵列模型。我们的模型能够再现动作电位的特征。此外，我们调查MMG模型配置方面的灵敏度，如体积几何形状，纤维方向和起搏器位置。我们的数值计算结果表明，纤维取向和起搏器的位置是很大程度上影响MMG的SARA设备测量的关键方面。我们的结论是，球是适当的体积几何的近似。初步步骤验证模型对真实的MMG测量。我们的研究结果表明，该模型是灵活的，以模仿有限传播的磁签名在出现和衰减的子宫收缩。
Understanding the mechanisms of uterine contractions during pregnancy is especially important in predicting the onset of labor and thus in forecasting preterm deliveries. Preterm birth can cause serious health problems in newborns, as well as large financial burdens to society. Various techniques such as electromyography (EMG) and magnetomyography (MMG) have been developed to quantify uterine contractions. However, no widely accepted method to predict labor based on electromagnetic measurement is available. Therefore, developing a biophysical model of EMG and MMG could help better understand uterine contractions, interpret real measurements, and detect labor. In this work, we propose a multiscale realistic model of uterine contractions during pregnancy. At the cellular level, building on bifurcation theory, we apply generalized FitzHugh-Nagumo (FHN) equations that produces both plateau-type and bursting-type action potentials. At the tissue level, we introduce a random fiber orientation model applicable to an arbitrary uterine shape. We also develop an analytical expression for the propagation speed of transmembrane potential. At the organ level, a realistic volume conductor geometry model is provided based on magnetic resonance images of a pregnant woman. To simulate the measurements from the SQUID Array for Reproductive Assessment (SARA) device, we propose a sensor array model. Our model is able to reproduce the characteristics of action potentials. Additionally, we investigate the sensitivity of MMG to model configuration aspects such as volume geometry, fiber orientation, and pacemaker location. Our numerical results show that fiber orientation and pacemaker location are the key aspects that greatly affect the MMG as measured by the SARA device. We conclude that sphere is appropriate as an approximation of the volume geometry. The initial step towards validating the model against real MMG measurement is also presented. Our results show that the model is flexible to mimic the limited-propagation magnetic signature during the emergence and decay of a uterine contraction.