Ford N L, Martin E L, Lewis J F, Veldhuizen R A W, Drangova M, Holdsworth D W
Robarts Research Institute, London, ON, Canada N6A5K8.
J Appl Physiol (1985). 2007 May;102(5):2046-55. doi: 10.1152/japplphysiol.00629.2006. Epub 2007 Jan 25.
Lung morphology and function in human subjects can be monitored with computed tomography (CT). Because many human respiratory diseases are routinely modeled in rodents, a means of monitoring the changes in the structure and function of the rodent lung is desired. High-resolution images of the rodent lung can be attained with specialized micro-CT equipment, which provides a means of monitoring rodent models of lung disease noninvasively with a clinically relevant method. Previous studies have shown respiratory-gated images of intubated and respirated mice. Although the image quality and resolution are sufficient in these studies to make quantitative measurements, these measurements of lung structure will depend on the settings of the ventilator and not on the respiratory mechanics of the individual animals. In addition, intubation and ventilation can have unnatural effects on the respiratory dynamics of the animal, because the airway pressure, tidal volume, and respiratory rate are selected by the operator. In these experiments, important information about the symptoms of the respiratory disease being studied may be missed because the respiration is forced to conform to the ventilator settings. In this study, we implement a method of respiratory-gated micro-CT for use with anesthetized free-breathing rodents. From the micro-CT images, quantitative analysis of the structure of the lungs of healthy unconscious mice was performed to obtain airway diameters, lung and airway volumes, and CT densities at end expiration and during inspiration. Because the animals were free breathing, we were able to calculate tidal volume (0.09 +/- 0.03 ml) and functional residual capacity (0.16 +/- 0.03 ml).
人体肺部的形态和功能可通过计算机断层扫描（CT）进行监测。由于许多人类呼吸系统疾病通常在啮齿动物身上建模，因此需要一种监测啮齿动物肺部结构和功能变化的方法。使用专门的微型CT设备可以获得啮齿动物肺部的高分辨率图像，这提供了一种通过临床相关方法对肺部疾病的啮齿动物模型进行无创监测的手段。先前的研究已经展示了插管并通气的小鼠的呼吸门控图像。尽管这些研究中的图像质量和分辨率足以进行定量测量，但这些肺部结构测量将取决于呼吸机的设置，而非个体动物的呼吸力学。此外，插管和通气可能会对动物的呼吸动力学产生非自然的影响，因为气道压力、潮气量和呼吸频率是由操作人员选择的。在这些实验中，由于呼吸被迫符合呼吸机设置，可能会错过有关所研究呼吸系统疾病症状的重要信息。在本研究中，我们实施了一种用于麻醉自由呼吸啮齿动物的呼吸门控微型CT方法。从微型CT图像中，对健康无意识小鼠的肺部结构进行了定量分析，以获得气道直径、肺和气道容积以及呼气末和吸气时的CT密度。由于动物是自由呼吸的，我们能够计算出潮气量（0.09±0.03毫升）和功能残气量（0.16±0.03毫升）。
