Local Strain Distribution in Real Three-Dimensional Alveolar Geometries
Local Strain Distribution in Real Three-Dimensional Alveolar Geometries
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DOI：
10.1007/s10439-011-0328-z
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发表时间：
2011-11-01
影响因子：
3.8
通讯作者：
Wall, W. A.
中科院分区：
文献类型：
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作者：
Rausch, S. M. K.;Haberthuer, D.;Wall, W. A.
机械通气不仅是一种挽救生命的治疗方法，而且还会引起不良反应。主要并发症之一是肺泡组织过度伸展引起的炎症。此前，研究要么调查全球菌株，要么调查哪些状态会导致细胞培养中的炎症反应。然而，组织条或整个器官的整体变形与到达肺泡壁内单个细胞的应变之间的联系尚不清楚，各自的研究仍然缺乏。其主要原因很可能是复杂的海绵状肺泡结构，其三维细节直到最近才为人所知。利用基于同步加速器的X射线断层扫描显微镜，我们能够生成真实和详细的三维牙槽几何图形，并对其进行有限元模拟。这使得我们第一次能够确定肺泡壁内的三维应变状态。简单地说，从分离的大鼠肺制备的精密切割的肺切片被扫描和分割，以提供三维几何图形。然后使用新开发的四面体单元对其进行离散化。这项研究的主要结论是，肺泡壁的局部应变可以达到全局应变的数倍，因为我们的模拟高达四倍，而且薄的结构显然会导致特别有可能过度拉伸的热点。
Mechanical ventilation is not only a life saving treatment but can also cause negative side effects. One of the main complications is inflammation caused by overstretching of the alveolar tissue. Previously, studies investigated either global strains or looked into which states lead to inflammatory reactions in cell cultures. However, the connection between the global deformation, of a tissue strip or the whole organ, and the strains reaching the single cells lining the alveolar walls is unknown and respective studies are still missing. The main reason for this is most likely the complex, sponge-like alveolar geometry, whose three-dimensional details have been unknown until recently. Utilizing synchrotron-based X-ray tomographic microscopy, we were able to generate real and detailed three-dimensional alveolar geometries on which we have performed finite-element simulations. This allowed us to determine, for the first time, a three-dimensional strain state within the alveolar wall. Briefly, precision-cut lung slices, prepared from isolated rat lungs, were scanned and segmented to provide a three-dimensional geometry. This was then discretized using newly developed tetrahedral elements. The main conclusions of this study are that the local strain in the alveolar wall can reach a multiple of the value of the global strain, for our simulations up to four times as high and that thin structures obviously cause hotspots that are especially at risk of overstretching.