Department of Mechanical and Aerospace Engineering, University of California, Davis, CA 95616, USA.
Ann Biomed Eng. 2011 Jun;39(6):1805-14. doi: 10.1007/s10439-011-0279-4. Epub 2011 Feb 23.
Neonatal and postnatal exposures to air pollutants have adverse effects on lung development resulting in airway structure changes. Usually, generation-averaged analysis of airway geometric parameters is employed to differentiate between pulmonary airway trees. However, this method is limited, especially for monopodial branching trees such as in rat airways, because both quite proximal and less proximal airways that have very different structure and function may be in the same generation. To avoid limitations inherent in generation averaging, we developed a method that compares two trees airway-by-airway using micro CT image data from rat lungs. This computerized technique (1) identifies the geometry and architecture of the conducting airways from CT images, (2) extracts the main tree, (3) associates paired airways from the two different trees, and (4) develops summary statistics on the degree of similarity between populations of animals. By comparing the trees airway-by-airway, we found that the variance in airway length of the group exposed to diffusion flame particles (DFP) is significantly larger than the group raised in filtered air (FA). This method also found that rotation angle of the DFP group is significantly larger than FA, which is not as certain in the generation-based analysis. We suggest that airway-by-airway analysis complements generation-based averaging for detecting airway alterations.
新生儿和产后暴露于空气污染物会对肺发育产生不良影响，导致气道结构发生变化。通常，采用气道几何参数的代际平均分析来区分肺气道树。然而，这种方法存在局限性，特别是对于像大鼠气道那样的单轴分枝树，因为非常近端和不太近端的气道具有非常不同的结构和功能，它们可能处于同一代际中。为了避免代际平均固有的局限性，我们开发了一种方法，该方法使用大鼠肺部的 micro CT 图像数据逐气道比较两棵树。这种计算机技术（1）从 CT 图像中识别出传导气道的几何形状和结构，（2）提取主树，（3）将来自两棵不同树的成对气道关联起来，以及（4）针对动物种群之间的相似性程度制定汇总统计数据。通过逐气道比较树，我们发现暴露于扩散火焰颗粒（DFP）的组的气道长度方差明显大于在过滤空气中饲养的组。该方法还发现，DFP 组的旋转角度明显大于 FA，而在基于代际的分析中则不太确定。我们建议，逐气道分析补充了基于代际的平均分析，以检测气道改变。
