TECHNIQUE FOR MEASUREMENT OF FRACTIONAL VENTILATION IN LARGE SPECIES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 阻塞性和限制性肺部疾病，如肺气肿、哮喘和囊性纤维化 影响肺部气体流动，从而影响局部肺通气量。非侵入性 因此，对局部肺功能的评估在量化严重程度方面至关重要。 评估对治疗的反应，预测临床结果。肺 功能测试(如肺活量测定和弥散能力)提供了一种廉价、但不敏感和 只是对肺功能的全球测量，这可能对区域性肺异常不敏感。其他 常见的临床肺部成像技术(如放射性核素通风-灌注核素扫描和 放射性气溶胶)提供了有关区域通风的定性信息， 空间分辨率和对放射性物质的暴露。基于交付的定量技术/ 清晰率氙气对比CT图像也已开发出来。新技术的出现 然而，超极化(HP)3He磁共振成像提供了一套独特的非侵入性 通风空间的可视化。早期的技术是用来测量肺通气量的 使用这项技术仅限于在啮齿类动物身上使用，因为它们使用许多HP 3He呼吸和 因此需要相对较长的采集时间和不可行的3He量 一次成像治疗。该项目中开发的分段通风成像技术可以 表现得更快，需要更少的3He呼吸，而且显示出良好的状态 与在啮齿动物身上演示的较老的方法一致。这些功能使该技术成为一种 适用于较大物种以及人类受试者的通风成像方法。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Obstructive and restrictive lung diseases such as emphysema, asthma, and cystic fibrosis adversely affect gas flow in the lungs, and therefore compromise regional lung ventilation. Noninvasive assessment of regional lung function is therefore of critical importance in quantifying the severity of the disease, evaluating response to therapy, and predicting the clinical outcome. Pulmonary function tests (such as spirometry and diffusing capacity) provide an inexpensive, yet insensitive and only a global measure of lung function, which can be insensitive to regional lung abnormalities. Other common clinical lung imaging techniques (such as radionuclide ventilation-perfusion scintigraphy and radioactive aerosols) provide qualitative information about regional ventilation and suffer from poor spatial resolution and exposure to radioactive materials. Quantitative techniques based on delivery/ clearance rates xenon-contrast CT images have also been developed. The emergence of hyperpolarized (HP) 3He MRI however has provided a unique set of capabilities in noninvasive visualization of ventilated airspaces. Earlier techniques developed to measure lung ventilation using this technology were limited to use in rodents, since they utilize many HP 3He breaths and consequently require a relatively long acquisition time and an infeasible amount of 3He available in one imaging session. The fractional ventilation imaging technique developed in this project can be performed much faster, requires substantially fewer 3He breaths, and is shown to be in good agreement with older methods as demonstrated in rodents. These features make this technique a suitable approach in ventilation imaging in larger species as well as in human subjects.