Thomas S R, Gradon L, Pratsinis S E, Pratt R G, Fotou G P, McGoron A J, Podgorski A L, Millard R W
Department of Radiology, University of Cincinnati, Ohio 45267-0579, USA.
Invest Radiol. 1997 Jan;32(1):29-38. doi: 10.1097/00004424-199701000-00005.
Perfluorocarbon (PFC) aerosols present the opportunity for simultaneous analysis of lung structure and pulmonary oxygenation patterns. The authors investigated techniques to nebulize neat liquid PFCs for inhalation as a new method of PFC administration and tested the hypothesis that PFC aerosols may be developed for efficient delivery to the lung in an experimental rat model allowing the potential for sequential monitoring of pulmonary status via quantitative fluorine-19 (19F) magnetic resonance (MR) partial pressure of oxygen (pO2) imaging.
Pneumatic aerosol generators were configured to produce a neat liquid PFC perfluorotributylamine (FC-43) aerosol. Perfluorocarbon inhalation breathing protocols for the rat model included: spontaneous direct breathing from an aerosol chamber, and use of a tracheotomy tube to bypass nasal breathing. The PFC aerosol delivery into the rat lung was documented through 19F MR imaging in correlation with high-resolution anatomic proton MR images. Theoretical model calculations for PFC mass deposition were compared with experimental results.
The pneumatic generator produced a PFC aerosol droplet within the theoretically targeted range (geometric mean particle diameter of 1.2 microns; concentration of approximately 4 x 10(7) droplets per cm3). No measurable aerosol reached the lungs during spontaneous breathing because of the efficient filtering capabilities of the turbinated nasal passages. With tracheotomy, aerosol depositions within the lung were achieved in mass quantities consistent with theoretical expectations; however, the distribution patterns were nonuniform and unpredictable. Oxygen-enhanced 19F imaging was demonstrated.
Perfluorocarbon aerosols of controlled size distribution can be produced at sufficient concentration with pneumatic generators for distribution to the terminal pulmonary architecture and visualization using 19F MR imaging. The potential exists for in vivo oxygen-sensitive imaging in the pulmonary system and development of sophisticated experimental animal models of systemic oxygen transport as a function of pulmonary status.
全氟化碳（PFC）气雾剂为同时分析肺结构和肺氧合模式提供了契机。作者研究了将纯液态PFC雾化以供吸入的技术，作为一种新的PFC给药方法，并在实验大鼠模型中检验了以下假设：可开发PFC气雾剂，以有效递送至肺部，从而有可能通过定量氟-19（¹⁹F）磁共振（MR）氧分压（pO₂）成像对肺部状态进行连续监测。
配置气动气雾剂发生器以产生纯液态PFC全氟三丁胺（FC-43）气雾剂。大鼠模型的全氟化碳吸入呼吸方案包括：从气雾剂室进行自主直接呼吸，以及使用气管切开管绕过鼻呼吸。通过¹⁹F MR成像记录PFC气雾剂在大鼠肺内的递送情况，并与高分辨率解剖质子MR图像相关联。将PFC质量沉积的理论模型计算结果与实验结果进行比较。
气动发生器产生的PFC气雾剂液滴在理论目标范围内（几何平均粒径为1.2微米；浓度约为每立方厘米4×10⁷个液滴）。由于鼻甲鼻道的高效过滤能力，自主呼吸期间没有可测量的气雾剂到达肺部。通过气管切开术，肺部实现了与理论预期一致的大量气雾剂沉积；然而，分布模式不均匀且不可预测。证明了氧增强¹⁹F成像。
气动发生器能够以足够的浓度产生尺寸分布可控的全氟化碳气雾剂，用于递送至终末肺结构并通过¹⁹F MR成像进行可视化。在肺系统中进行体内氧敏感成像以及开发作为肺部状态函数的复杂全身氧运输实验动物模型具有潜力。
