Biomagnetic characterization of gastric dysrhythmias

描述（由申请人提供）：胃肠道系统疾病影响很大一部分人群，但很少有诊断技术提供关于基础生理学和病理生理学的可靠细节，尽管最近的进展已经阐明了Cajal间质细胞作为胃电活动（GEA）起搏器和传播者的作用，但这些细节仍然没有得到很好的理解。皮肤胃电图（EGG）是唯一常用的方法来评估GEA非侵入性。在过去的12年里，我们的小组已经表明，胃磁图（MGG）准确地反映了正常的内部GEA和异常情况下引起的胃慢波的变化。MGG避免了EGG固有的许多问题，因为它测量的是磁场而不是电势，而电势是由腹部平滑和衰减的。除了可以从皮肤EGG确定的信号频率动态之外，多通道矢量MGG还提供GEA传播的时空表征。来自我们最先进的临床设施，范德比尔特大学胃肠道SQUID技术（VU-GIST）实验室的研究已经证明了磁检测与糖尿病胃轻瘫相关的胃解偶联和尖峰电反应活动（ERA）的能力。在本提案中，我们希望进一步研究MGG和EGG评估GEA的相对能力。我们将研究（1）腹部容积传导和体重指数（BMI）对EGG和MGG慢波的影响，（2）由糖尿病和特发性胃轻瘫引起的EGG和MGG的变化，（3）减少和增强GEA对EGG和MGG的药理学作用，（4）EGG和MGG非侵入性检测棘突ERA的相对能力以及腹层对棘突ERA检测的影响。除了我们的外部非侵入性测量皮肤EGG和MGG，我们将设计和构建一个腔内鼻胃导管，使我们能够同时测量腔内胃压力和粘膜电活动。这些同步测量将帮助我们将外部EGG和MGG中观察到的事件与实际的内部电和机械活动相关联。我们期望MGG将提供一种新的、非侵入性的方法来帮助描述各种胃部疾病，包括糖尿病和特发性胃轻瘫

DESCRIPTION (provided by applicant): Disorders of the gastrointestinal system impact a significant portion of the population, yet few diagnostic techniques provide reliable details about underyling physiology .and pathophysiology, which are still not well understood despite recent advances that have elucidated the role of interstitial cells of Cajal as the pacemakers and propagators of gastric electrical activity (GEA). Cutaneous electrogastrography (EGG) represents the only commonly available method to assess GEA noninvasively. Over the past 12 years, our group has shown that the magnetogastrogram (MGG) accurately reflects both normal internal GEA and changes to the gastric slow wave caused by abnormal conditions. The MGG avoids many of the problems inherent to the EGG since it measures magnetic fields instead of electric potentials, which are smoothed and attenuated by the abdomen. In addition to signal frequency dynamics, which can be determined from cutaneous EGG, multichannel vector MGG also provides for a spatiotemporal characterization of the propagation of GEA. Studies from our new state-of-the-art clinical facility, the Vanderbilt University Gastrointestinal SQUID Technology (VU-GIST) Laboratory have demonstrated the ability to detect gastric uncoupling associated with diabetic gastroparesis and the spiking electrical response activity (ERA) magnetically. In this proposal, we wish to further investigate the relative ability of the MGG and EGG to assess GEA. We will study (1) the effect of abdominal volume conduction and body mass index (BMI) on the EGG and MGG slow waves, (2) changes in the EGG and MGG resulting from diabetic and idiopathic gastroparesis, (3) the effect of pharmacological agents that both reduce and enhance GEA on the EGG and MGG, and (4) the relative ability of the EGG and MGG to noninvasively detect spiking ERA and the influence of abdominal layers on the detection of spiking ERA. In addition to our external noninvasive measurements of cutaneous EGG and MGG, we will design and construct an intraluminal nasogastric catheter that will allow us to simultaneously measure intraluminal gastric pressure and mucosal electrical activity. These simultaneous measurements will help us correlate events observed in external EGG and MGG with the actual internal electrical and mechanical activities. We expect that the MGG will provide a new, noninvasive method to help characterize a variety of gastric disorders, including diabetic and idiopathic gastroparesis