Admittance to measure cardiac mechanics in mice

测量小鼠心脏力学的准入

• 批准号: 7038599
• 负责人: MARC David FELDMAN
• 金额: $ 18.92万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7038599
• 关键词: bioimaging /biomedical imaging; biomedical equipment development; blood flow measurement; clinical biomedical equipment; computer data analysis; computer simulation; computer system hardware; electrical conductance; genetically modified animals; heart contraction; heart imaging /visualization /scanning; heart ventricle; hemodynamics; laboratory mouse; magnetic resonance imaging; mathematical model; miniature biomedical equipment; myocardium; telemetry

DESCRIPTION (provided by applicant): Genetically altered mice provide a mechanism to define the in vivo phenotype of individual genes. This is especially relevant to genes implicated in producing myocardial diseases leading to congestive heart failure. The classic method to assess the hemodynamic phenotype in larger animals is through left ventricular (LV) pressure-volume (PV) analysis. However, determining absolute and instantaneous volume in the murine LV has been plagued by its small size and rapid heart rate. Conductance measurements offer an attractive solution to this problem by generating an instantaneous LV volume signal compatible with any myocardial size or heart rate. Unfortunately, the first generation conductance instrument generates an instantaneous conductance (volume) signal composed of blood and myocardium even at a single lower frequency. Only the blood component is desired for PV analysis. A mechanism to overcome this limitation is proposed by measuring admittance (complex conductance). Admittance is composed of both the magnitude of LV blood and myocardial conductance, and the phase angle of myocardial conductance. Traditional single frequency conductance measures only the magnitude of the conductance signal, which includes both the blood and myocardial components. Because measurable phase angle is unique to muscle, admittance offers a better method to determine and remove the instantaneous myocardial contribution to the combined LV conductance (volume) signal. The GOAL of this grant application is to develop, calibrate, and validate an INSTRUMENT to measure both the magnitude and the phase angle of the admittance signal in real time. To accomplish this goal, we will - 1) Develop both analog hardware and digital data acquisition Admittance Instruments, 2) Develop a more accurate method to derive LV volume from admittance measurements using FEM, and 3) Demonstrate that an Admittance Instrument is superior to traditional single frequency with MRI.

描述（由申请人提供）：基因改造小鼠提供了一种定义个体基因体内表型的机制。这与产生导致充血性心力衰竭的心肌疾病有关的基因尤其相关。评估大型动物血流动力学表型的经典方法是通过左心室 (LV) 压力-容积 (PV) 分析。然而，测定小鼠左心室的绝对和瞬时容量一直因其体积小和心率快而受到困扰。电导测量通过生成与任何心肌大小或心率兼容的瞬时左心室容量信号，为该问题提供了一种有吸引力的解决方案。不幸的是，第一代电导仪即使在单个较低频率下也会产生由血液和心肌组成的瞬时电导（体积）信号。 PV 分析仅需要血液成分。通过测量导纳（复电导）提出了克服此限制的机制。导纳由左心室血液和心肌电导的幅度以及心肌电导的相位角组成。传统的单频电导仅测量电导信号的幅度，其中包括血液和心肌成分。由于可测量的相位角是肌肉所独有的，因此导纳提供了一种更好的方法来确定和消除瞬时心肌对组合左心室电导（容量）信号的贡献。该拨款申请的目标是开发、校准和验证仪器以实时测量导纳信号的幅度和相位角。为了实现这一目标，我们将 - 1) 开发模拟硬件和数字数据采集导纳仪器，2) 开发一种更准确的方法，使用 FEM 从导纳测量中导出 LV 体积，以及 3) 证明导纳仪器优于传统导纳仪器单频 MRI。