Acoustic System for Diagnosis of Pneumonia and Pneumothorax using Transfer Function Analysis

项目摘要/摘要 每年，肺炎是全世界100多万人的死因，其中大多数死亡 发生在无法获得先进医疗基础设施的地区。当前的临床黄金 诊断肺炎的标准是胸部x光，虽然对诊断有效，但通常不能用于诊断。 由于抑制的财务成本，患者处于资源有限的环境中。对于这些人群来说，物理上 检查提供了一种可获得的、方便的和低成本的选择-因此，所有的医生都接受了 进行体检。敲击的体检技术是通过敲击特定的区域来进行的 并评估产生的声音是否对应于健康或患病的组织。 不幸的是，医生技术的不同导致了不一致的发现和敲击的驳回。 方法，当X光机可用时。我们的设备的目标是量化这些发现，以消除 观察者之间的误差和利用敲击的诊断能力提供低成本、定量的物理 用于诊断胸腔受限人群肺炎的检查工具 放射摄影术。我们已经开发了一种为胸部提供声学刺激的原型设备；声音是 用电子听诊器从背部记录下来，这个记录被用来评估胸部 腔体的声学传递函数。传递函数表征了系统对 不同的频率，可以用来区分不同的系统。我们的具体目标集中在 发展了一种研究结构变化对声学传递函数影响的方法 肺炎期间的肺部(目标1)和探讨该方法在气胸治疗中的普适性 特别是其他肺部病变(目标2)。在目标1中，我们假设 肺炎患者的肺叶渗出(液体)将导致更高频率的声音更好地传播。 与健康的肺相比。首先，我们将使用密度与人类肺组织相似的海绵进行成像 Phantom，以提高我们设备的信噪比并简化数据分析。第二，我们将表演 我们在患者身上进行的实验将他们健康的一侧肺与患有大叶性肺炎的一侧进行了比较。最后， 我们将开发一个分类器，它可以考虑其他变量，如年龄和性别 改进我们测试的性能，并根据声学发现返回肺炎的严重程度评分。为了达到目标 我们的假设是，胸腔内空气的积聚会减少声音的传播，特别是 以更高的频率。我们将首先进行一个充气空腔(胃)与固体的对比实验 组织(膝关节)，以确定空气积聚对传递功能的影响。接下来，就像在目标1中一样，我们将 在患者身上进行测试，比较有气胸的一侧和健康侧。最后，我们会 开发一种分类器来提供气胸的严重程度评分。我们预计来自我们的调查结果 研究将为肺炎和气胸的声学诊断的可行性提供新的见解。

PROJECT SUMMARY/ABSTRACT Every year pneumonia is the cause of death for over a million people worldwide, with most of these deaths occurring in areas that do not have access to advanced medical infrastructure. The current clinical gold standard for detecting pneumonia is a chest x-ray, which, while effective for diagnosis, is often unavailable to patients in resource limited settings due to inhibitive financial costs. For these populations, physical examinations provide an accessible, convenient, and low-cost alternative---thus, all doctors are trained to perform the physical exam. The physical exam technique of percussion is performed by tapping specific areas of the back and assessing whether the resulting sound corresponds to healthy or diseased tissue. Unfortunately, differences in physician technique lead to inconsistent findings and dismissal of the percussion method when x-ray machines are available. The goal of our device is to quantify these findings to eliminate interobserver error and harness the diagnostic power of percussion to provide a low-cost, quantitative physical examination tool for the diagnosis of pneumonia in patient populations with limited access to chest radiography. We have developed a prototype device that provides acoustic stimulation to the chest; sound is recorded from the back using an electronic stethoscope and this recording is used to estimate the chest cavity's acoustic transfer function. The transfer function characterizes the strength of response of a system to different frequencies and can be used to distinguish between different systems. Our specific aims focus on developing a method to study the effects on the acoustic transfer function due to structural changes in the lungs during pneumonia (Aim 1) and to explore the generalizability of this approach to pneumothorax specifically as well as other lung pathologies (Aim 2). In Aim 1, we hypothesize that the accumulation of exudate (fluid) in a lobe of the lungs in pneumonia will lead to better sound transmission of higher frequencies compared to healthy lung. First, we will use a sponge with similar density to human lung tissue as an imaging phantom to improve our device's signal-to-noise ratio and streamline data analysis. Second, we will perform our experiments in patients comparing the healthy side of their lungs to the side with lobar pneumonia. Finally, we will develop a classifier that can take additional variables such as age and gender into consideration to improve performance of our test and return a severity score of pneumonia based on acoustic findings. For Aim 2, our hypothesis is that the accumulation of air in pleural spaces will reduce transmission of sound, especially at higher frequencies. We will first perform an experiment with an air-filled cavity (stomach) compared to solid tissue (knee) to determine the effect of air accumulation on the transfer function. Next, as in Aim 1, we will perform tests on patients comparing the side with the pneumothorax to the healthy side. Finally, we will develop a classifier to provide a severity score of pneumothorax. We anticipate that the findings from our studies will provide novel insight into the feasibility of acoustic diagnosis of pneumonia and pneumothorax.