Imaging Blood Flow, Ventilation, and Density Interactions

血流、通气和密度相互作用成像

• 批准号: 9103894
• 负责人: Susan R Hopkins
• 金额: $ 63.25万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9103894
• 关键词: Adoption; Adult Respiratory Distress Syndrome; Affect; Alveolar; Biological Markers; Blood Vessels; Blood flow; Blood gas; Carbon Dioxide; Chest; Clinic; Clinical; Clinical Data; Collaborations; Data; Databases; Elements; Environmental air flow; Evaluation; Fluid Balance; Force of Gravity; Functional Magnetic Resonance Imaging; Gases; Goals; Health; Image; Imaging Techniques; Intervention; Lung; Magnetic Resonance Imaging; Measurement; Measures; Mechanics; Methods; Modeling; Outcome; Partial Pressure; Patient Care; Patient-Focused Outcomes; Patients; Perfusion; Persons; Physiological; Physiology; Positive-Pressure Respiration; Posture; Prone Position; Protons; Pulmonary Edema; Pulmonary Gas Exchange; Quantitative Evaluations; Recruitment Activity; Regional Blood Flow; Retrospective Studies; Shapes; Side; Stretching; Testing; Tissue Model; Tissues; Translations; Universities; Weight; Work; X-Ray Computed Tomography; base; clinically relevant; density; healthy aging; improved; innovation; lung injury; lung pressure; patient biomarkers; pressure; response; survival prediction

 DESCRIPTION (provided by applicant): There is a strong influence of gravity on the lung. The lung deforms under its own weight, stretching some regions and compressing others, affecting ventilation and blood flow. The deformation is strongly posture dependent because the thorax (the "container shape") is not symmetrical. This asymmetry can be envisioned as a wedge, with the lung hanging from the shorter side in supine posture and the longer side in prone. The effects of asymmetry and gravity are additive in supine posture, but oppose one another in prone. Goal/Significance Early adoption of prone ventilation in severe Acute Respiratory Distress Syndrome (ARDS) markedly improves survival. This is especially true if arterial partial pressure of CO2 and dead space are decreased by prone posture, implying that this intervention recruits blood flow to match regions of well-ventilated lung. Our goal is to understand the mechanisms by which lung deformation and thoracic shape interact to affect pulmonary blood flow and gas exchange. Since prone ventilation greatly complicates patient care, understanding posture effects on blood flow distribution is critically important. This information will be to develop patient-specific metrics to identify which ARDS patients might benefit most from prone ventilation. This work may have other implications for patient management including fluid balance and inotropic therapy. Innovation Can the effects of prone posture on pulmonary blood flow and gas exchange be predicted from regional lung density distribution measured supine? To answer this question we have developed a suite of functional magnetic resonance imaging techniques that allow regional quantification of lung proton density, alveolar ventilation, and perfusion. This allows the evaluation of how container shape and lung deformation alter ventilation-perfusion (VA/Q) matching and regional dead space under clinically relevant conditions. We propose to combine our sophisticated imaging techniques with person-specific modeling of tissue deformation in collaboration with Dr. Merryn Tawhai (University of Auckland) to calculate regional tissue deformation and trans-pulmonary pressure gradients and evaluate the effect on local blood flow and VA/Qmatching. Approach we will test the hypothesis that regions of highly stretched (high local trans-pulmonary pressure) lung corresponding to regions of high V /Q ratio in supine posture will be reduced in prone posture. A resulting in more uniform V /Q matching. In normal subjects we will use data acquired in supine posture A combined with person-specific modeling to predict the effects on blood flow and VA/Q matching in prone posture, and test our predictions against measurements made in prone posture. This information will be used to develop biomarkers for optimal blood flow based on density distribution and thoracic shape (and thus measureable with routine clinical CT) that predict improvement with prone posture. This will be tested in collaboration with Dr. Harm Bogaard (VU Univ. Amsterdam) in a retrospective study of patients with ARDS who have undergone prone ventilation.

 描述（申请人提供）：重力对肺部有很强的影响。肺在自身重量下变形，拉伸某些区域并压缩其他区域，影响通气和血液流动。变形是强烈的姿势依赖性，因为胸部（“容器形状”）是不对称的。这种不对称性可以想象成一个楔形，仰卧位时肺从短侧悬挂，俯卧位时肺从长侧悬挂。不对称性和重力的影响在仰卧姿势中是相加的，但在俯卧姿势中是相互对立的。 在严重急性呼吸窘迫综合征（ARDS）中早期采用俯卧位通气可显著提高生存率。如果俯卧位降低了二氧化碳和死腔的动脉分压，这一点尤其正确，这意味着这种干预招募了血流以匹配通气良好的肺区域。我们的目标是了解肺变形和胸廓形状相互作用影响肺血流和气体交换的机制。由于俯卧通气使患者护理变得非常复杂，因此了解体位对血流分布的影响至关重要。这些信息将用于制定患者特定的指标，以确定哪些ARDS患者可能从俯卧通气中获益最多。这项工作可能有其他的影响，病人的管理，包括液体平衡和正性肌力治疗。 创新俯卧位对肺血流和气体交换的影响能否从仰卧位测量的局部肺密度分布来预测？为了回答这个问题，我们开发了一套功能性磁共振成像技术，可以对肺质子密度、肺泡通气和灌注进行区域定量。这允许在临床相关条件下评价容器形状和肺变形如何改变通气-灌注（VA/Q）匹配和局部死腔。我们建议与Merryn Tawhai博士（奥克兰大学）合作，将我们先进的成像技术与组织变形的个人特定建模相结合，以计算局部组织变形和跨肺压差，并评估对局部血流和VA/Q匹配的影响。 方法我们将检验以下假设：仰卧位时对应于高V /Q比区域的高度拉伸（高局部经肺压）肺区域将在俯卧位时减少。A导致更均匀的V /Q匹配。在正常受试者中，我们将使用仰卧姿势A采集的数据结合个人特定建模来预测俯卧姿势对血流和VA/Q匹配的影响，并根据俯卧姿势的测量结果来测试我们的预测。该信息将用于基于密度分布和胸部形状（因此可通过常规临床CT测量）开发最佳血流的生物标志物，以预测俯卧位的改善。这将与Harm Bogaard博士（阿姆斯特丹自由大学）合作，在一项对接受俯卧通气的ARDS患者的回顾性研究中进行测试。