Biomagnetic characterization of gastric dysrhythmias

描述（由申请人提供）：胃电活动是功能生理学和病理生理学的基础。我们的初步数据表明，与胃慢波相关的磁场包含有助于表征节奏的关键参数，可能是胃病的重要指标。虽然胃电图（EGG）和胃磁图（MGG）都包含与胃肌肉组织肌电位相关的频率，但MGG中附加的时空信息可以评估胃的传播。我们已经表明，当比较正常受试者与胃轻瘫患者时，MGG的繁殖特征不同。我们还能够通过无创MGG测量计算胃合胞体的繁殖梯度，并显示其与浆膜电极数据的相关性。为了继续我们对胃磁场的研究，我们提出：(1)使用一个真实的腹部体积导体模型来研究腹部厚度如何影响EGG和MGG数据，以及正常和不耦合的胃肌肉组织如何影响EGG和MGG模式。我们的研究数据与我们最初的假设相矛盾，即身体质量指数（BMI）显著影响这些信号，这是基于预测腹部层影响的理论研究。我们将利用在这一目标下开发的模型来分析来自其他具体目标的实验数据。(2)我们拟确定胃切除术对EGG和MGG的影响。MGG观察到正常完整胃产生慢波传播模式。我们假设，虽然非胃信号可能出现在胃慢波频率范围附近，但这些信号不会表现出相同的胃传播。(3)我们将通过手术或药物诱导解偶联来确定胃解偶联如何改变MGG的繁殖模式，以测量EGG和MGG评估的繁殖和偶联的变化。(4)我们将胃轻瘫的程度与MGG的异常繁殖模式联系起来。我们发现胃轻瘫有多种异常繁殖模式，我们将确定这些模式差异是否能区分疾病的严重程度。(5)最后，我们将确定糖尿病和特发性胃轻瘫之间是否存在类似的差异，我们将确定患者之间存在多大的差异。从频率动态和传播特性两方面持续评估胃电活动的能力将有助于我们更好地了解潜在的病理，从而为胃轻瘫患者提供更好和更有效的治疗选择，并最终为患有各种胃部疾病的患者提供指导。

DESCRIPTION (provided by applicant): Electrical activity in the stomach underlies functional physiology and pathophysiology. Our preliminary data show that the magnetic fields associated with the gastric slow wave contain critical parameters that help to characterize rhythms and may be important indicators of gastropathy. While both the electrogastrogram (EGG) and the magnetogastrogram (MGG) contain frequencies that correlate well with myoelectric potentials in the gastric musculature, additional spatiotemporal information in the MGG allows assessment of gastric propagation. We have shown that MGG propagation characteristics differ when comparing normal subjects with gastroparesis patients. We have also been able to compute the propagation gradient of the gastric syncytium from noninvasive MGG measurements and have shown its correlation with serosal electrode data. To continue our research on the magnetic fields of the stomach, we are proposing: (1) to use a realistic abdominal volume-conductor model to study how abdominal thickness affects EGG and MGG data and how normal and uncoupled gastric musculature affects EGG and MGG patterns. Data from our studies contradicted our original hypothesis that body mass index (BMI) significantly affects these signals, which was based on theoretical studies that predict such influences from abdominal layers. We will utilize the model developed under this aim in the analysis of our experimental data from the other specific aims. (2) We propose to determine how gastrectomy affects EGG and MGG. The normal intact stomach produces slow wave propagation patterns observable with MGG. We hypothesize that although non-gastric signals may appear near the gastric slow wave frequency range, these signals will not exhibit the same gastric propagation. (3) We will determine how gastric uncoupling changes MGG propagation patterns by inducing uncoupling surgically or pharmacologically to measure the changes in propagation and coupling assessed by EGG and MGG. (4) We will correlate the degree of gastroparesis with abnormal patterns of MGG propagation. We showed that a variety of abnormal propagation patterns characterize gastroparesis and we will determine whether these pattern differences differentiate the severity of the disease. (5) Finally, we will determine whether similar differences exist between diabetic and idiopathic gastroparetics, and we will determine how much variation exists between patients. The ability to consistently evaluate the electrical activity of the stomach in terms of both frequency dynamics and propagation characteristics will help us to better understand underlying pathologies that will in turn inform and direct better and more effective treatment options for gastroparesis patients, and ultimately for patients suffering a variety of gastric disorders. PUBLIC HEALTH RELEVANCE: The magnetogastrogram (MGG) measures both the frequency content and spatiotemporal dynamics of underlying gastric slow wave electrical activity in health and disease. Pathological conditions like gastroparesis may not affect frequency content commonly measured by EGG, but do alter propagation patterns detected by MGG. The ability to noninvasively characterize gastric slow wave abnormalities will ultimately lead to a deeper understanding of gastric pathology and will inform treatment protocols.