Method for measuring ventilation-perfusion mismatches

描述(由申请人提供)： 通过这项建议，PI寻求开发一种先进的MRI技术来量化区域肺灌流/通气率，并使用该技术来进一步了解机械通气-灌流不匹配。这项提议将检验这样一种假设，即超极化(HP)MRI的极端敏感性可以用作高分辨率、间接检测肺通气-灌流(V/Q)不匹配的检测器。第二个假设是，HP-GAS MRI将允许量化V/Q错配，新方法可用于确定亚节段血栓的生理意义。具体目标：1)。量化HP-GAS MRI间接检测磁化率变化的灵敏度，并使用已建立的示踪剂动力学模型得出相对流量。2)。测定静脉注射Gd前后健康猪肺组织Hp~3He相图和T2~*图的变化。3)。评价HP-GAS MRI在肺血栓病例中检测节段性和亚节段性呼吸-灌流不匹配的能力。意义：定量的局部通气量和灌注量对于各种肺部疾病的诊断和治疗至关重要，包括肺血栓、哮喘、肺气肿和间质性肺疾病。V/Q不匹配的准确诊断需要高分辨率的区域肺灌注和通气性可视化。所提出的定量V/Q磁共振成像方法将为了解各种急、慢性肺部疾病的复杂作用机制提供有力的工具。这一结果将扩大我们检测和诊断肺部疾病的能力，肺部疾病是美国第四大死亡原因。

DESCRIPTION (provided by applicant): Through this proposal the PI seeks to develop an advanced MRI technique to quantify regional lung perfusion-ventilation ratios, and to use this technique to further understanding of ventilationperfusion mismatches. This proposal will test the Hypothesis that the extreme sensitivity of hyperpolarized (HP) MRI can be used as a high-resolution, indirect detector for lung ventilation-perfusion (V/Q) mismatches. A secondary hypothesis is that HP-gas MRI will allow for quantification of V/Q mismatches and that the new method can be used to establish the physiological significance of sub-segmental emboli. Specific Aims: 1). Quantify the sensitivity of HP-gas MRI to indirectly detect changes in susceptibility and derive relative flow using established tracer kinetics models. 2). Measure changes in alveolar HP 3He phase and T2* maps of the lungs of healthy pigs before and after intravenous injection of gadolinium. 3). Evaluate the capabilities of HP-gas MRI for detecting segmental and sub-segmental ventilation-perfusion mismatches in the case of pulmonary emboli. Significance: Quantification of regional ventilation and perfusion is of paramount importance for the diagnosis and treatment of a variety of pulmonary disorders, including pulmonary embolus, asthma, emphysema, and interstitial lung diseases. Accurate diagnosis of V/Q mismatches requires high-resolution visualization of regional lung perfusion and ventilation. The proposed method for quantifiable V/Q MRI will be a powerful tool in understanding the complex mechanisms acting during various acute or chronic lung diseases. The results will extend our abilities to detect and diagnose lung diseases, which are the 4th leading cause of death in the US.