Method for measuring ventilation-perfusion mismatches

描述（由申请人提供）： 通过该提案，PI寻求开发一种先进的MRI技术来量化局部肺灌注-通气比，并使用该技术进一步了解通气-灌注不匹配。本提案将检验超极化（HP）MRI的极高灵敏度可用作肺通气-灌注（V/Q）不匹配的高分辨率间接检测器的假设。次要假设是HP气体MRI将允许量化V/Q不匹配，并且新方法可用于确定亚段栓塞的生理意义。具体目标：1）。量化HP-气体MRI的灵敏度，以间接检测敏感性变化，并使用已建立的示踪剂动力学模型推导出相对流量。2）。测量健康猪静脉注射钆前后肺泡HP 3 He时相和T2* 图的变化。3）。评价HP-gas MRI检测肺栓塞病例中节段和亚节段通气-灌注不匹配的能力。重要性：局部通气和灌注的定量对于诊断和治疗各种肺部疾病（包括肺栓塞、哮喘、肺气肿和间质性肺病）至关重要。准确诊断V/Q不匹配需要高分辨率的局部肺灌注和通气可视化。所提出的方法可量化的V/Q MRI将是一个强大的工具，在了解各种急性或慢性肺部疾病的复杂机制。这些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.