TECHNIQUE FOR MEASUREMENT OF FRACTIONAL VENTILATION IN LARGE SPECIES

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 阻塞性和限制性肺部疾病，如肺气肿、哮喘和囊性纤维化， 影响肺部的气体流动，并因此损害局部肺通气。无创 因此，局部肺功能的评估在量化严重性方面至关重要 评估对治疗的反应，并预测临床结果。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， 仅是肺功能的整体测量，其可能对局部肺异常不敏感。其他 常见的临床肺成像技术（如放射性核素通气-灌注肺成像和 放射性气溶胶）提供关于区域通风的定性信息， 空间分辨率和暴露于放射性物质。基于交付的定量技术/ 清除率氙对比CT图像也已经开发出来。的出现 然而，超极化（HP）3 He MRI提供了一套独特的非侵入性功能， 通风空间的可视化。早期用于测量肺通气量的技术 使用这种技术仅限于啮齿动物，因为它们使用许多HP 3 He呼吸， 因此需要相对较长的获取时间和不可行的3 He可用量， 一个成像会议。本项目中开发的分数通气成像技术可以 进行得更快，需要更少的3 He呼吸，并且显示出良好的 与啮齿动物中证明的旧方法一致。这些特点使这项技术成为 在较大物种以及人类受试者中的通气成像中的合适方法。

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.