Method for measuring ventilation-perfusion mismatches

描述（由申请人提供）： 通过这项提案，PI 寻求开发一种先进的 MRI 技术来量化局部肺灌注-通气比率，并利用该技术进一步了解通气灌注不匹配。该提案将测试以下假设：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。第二个假设是 HP-gas MRI 将允许量化 V/Q 不匹配，并且新方法可用于确定亚节段栓塞的生理意义。具体目标： 1）。量化 HP 气体 MRI 的灵敏度，以间接检测磁化率的变化，并使用已建立的示踪动力学模型推导出相对流量。 2）。测量静脉注射钆前后健康猪肺泡 HP 3He 相和 T2* 图的变化。 3）。评估 HP-gas MRI 检测肺栓塞情况下节段和亚节段通气-灌注不匹配的能力。意义：区域通气和灌注的量化对于各种肺部疾病的诊断和治疗至关重要，包括肺栓塞、哮喘、肺气肿和间质性肺疾病。 V/Q 不匹配的准确诊断需要局部肺灌注和通气的高分辨率可视化。所提出的可量化 V/Q MRI 方法将成为理解各种急性或慢性肺部疾病期间复杂机制的有力工具。这些结果将提高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.