Spatial-Temporal Dynamics of Blood Flow in the Normal Human Lung

描述(由申请人提供)：这些研究的总体长期目标是了解肺血流被控制的机制，以及这种控制如何在健康和疾病中导致气体交换缺陷或优化。其具体目标是使用一种新的MRI技术来量化正常人类肺中血流的空间和时间动力学。许多生理系统中的时间异质性已被发现是健康功能的标志，但由于没有合适的工具来测量时间异质性，人们对人类肺内血流的时间动力学知之甚少。最近，我们发展了一种无创性的磁共振成像技术，提供了对人肺的肺血流量的定量测量，空间分辨率为1厘米3，时间分辨率为~10 S，使我们能够第一次检查人肺的时空异质性。这些特定目标旨在系统地探索时空异质性的正常频谱，测试：1)改变吸入气体(O2和CO2)对健康受试者的影响；2)运动的影响；3)衰老的影响；以及4)易受高原肺水肿影响的肺部O2和CO2改变的影响。这将是首次对受试者肺血流时空动力学进行系统、定量的研究，并将为将这些方法应用于疾病的早期检测和定性奠定基础。 公共卫生相关性：肺部血液的氧合依赖于通风和血液流动的紧密匹配：新鲜气体和血液流动需要在同一地点和同一时间。我们开发了一种新的成像技术，用于测量人类肺内血流的分布不仅在空间上，而且在时间上，这是以前不可能实现的测量。在这项工作中，我们将探索正常的血流动力学，作为应用这些方法来识别和更好地了解疾病的潜在机制的基础。

DESCRIPTION (provided by applicant): The overall long-term goal of these studies is to understand the mechanisms by which pulmonary blood flow is controlled, and how that control contributes to gas exchange defects or optimization in health and disease. The specific goal is to use a novel MRI technique to quantify the spatial and temporal dynamics of blood flow in the normal human lung. Temporal heterogeneity in a number of physiological systems has been found to be a mark of healthy function, yet little is known about the temporal dynamics of blood flow in the human lung because the appropriate tools for measuring temporal heterogeneity have not been available. Recently we developed a noninvasive MRI technique that provides quantitative measurements of pulmonary blood flow with a spatial resolution of <1 cm3 and a temporal resolution of ~10 s in the human lung, permitting us to examine spatial-temporal heterogeneity in the human lung for the first time. The Specific Aims are designed to systematically explore the normal spectrum of spatial-temporal heterogeneity, testing: 1) the effects of altered inspired gas (O2 and CO2) in healthy subjects; 2) the effects of exercise; 3) the effects of ageing; and 4) the effects of altered O2 and CO2 in the lungs of subjects susceptible to high altitude pulmonary edema. This will be the first systematic, quantitative study of the spatial and temporal dynamics of pulmonary blood flow in human subjects, and will lay a foundation for applying these methods in the early detection and characterization of disease. PUBLIC HEALTH RELEVANCE: Oxygenation of the blood in the lungs depends on a close matching of ventilation and blood flow: fresh gas and blood flow need to be at the same place and at the same time. We have developed a novel imaging technique for measuring the distribution of blood flow in the human lung not only spatially, but also over time, a measurement that has not been possible before. In this work we will explore the normal dynamics of blood flow as a foundation for applying these methods to identify, and to better understand, the underlying mechanisms of disease.