Analysis of Regional Mechanics in Canine Lung Injury Using Forced Oscillations and 3D Image Registration
Analysis of Regional Mechanics in Canine Lung Injury Using Forced Oscillations and 3D Image Registration
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DOI：
10.1007/s10439-010-0214-0
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发表时间：
2011-03-01
影响因子：
3.8
通讯作者：
Simon, Brett A.
中科院分区：
文献类型：
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作者：
Kaczka, David W.;Cao, Kunlin;Simon, Brett A.
急性肺损伤的特点是局部机械特性的异质性，这被认为与疾病的严重程度有关。评估使用呼吸输入阻抗(Z(Rs))和CT图像配准来评估实质力学异质性的可行性。在6只狗身上，测量油酸损伤前后不同扩张压力下的Z(Rs)，然后进行全肺CT扫描。每个Z(Rs)谱用包含区域顺应性的不同分布的模型进行拟合。使用图像配准算法匹配不同充气压力下的CT图像对，由此计算得到的解剖变形场的区域柔度分布。在基线条件下，平均模型顺应性随着充气压力的增加而降低，反映了实质的僵硬。肺损伤后，这些平均顺应性在每个压力下都会下降，这表明肺功能减退、肺泡泛滥或固有组织弹性改变。然而，平均遵从性并没有随着通胀压力的增加而改变，这与同时招募和紧张加剧是一致的。图像配准显示了区域顺应性的峰值分布，肺的一小部分在充气期间可能受到相对压缩。作者总结说，使用Z(Rs)评估肺功能，结合图像配准得出的结构变化，提供了与肺损伤相关的机械紊乱的独特但互补的信息。
Acute lung injury is characterized by heterogeneity of regional mechanical properties, which is thought to be correlated with disease severity. The feasibility of using respiratory input impedance (Z (rs)) and computed tomographic (CT) image registration for assessing parenchymal mechanical heterogeneity was evaluated. In six dogs, measurements of Z (rs) before and after oleic acid injury at various distending pressures were obtained, followed by whole lung CT scans. Each Z (rs) spectrum was fit with a model incorporating variable distributions of regional compliances. CT image pairs at different inflation pressures were matched using an image registration algorithm, from which distributions of regional compliances from the resulting anatomic deformation fields were computed. Under baseline conditions, average model compliance decreased with increasing inflation pressure, reflecting parenchymal stiffening. After lung injury, these average compliances decreased at each pressure, indicating derecruitment, alveolar flooding, or alterations in intrinsic tissue elastance. However, average compliance did not change as inflation pressure increased, consistent with simultaneous recruitment and strain stiffening. Image registration revealed peaked distributions of regional compliances, and that small portions of the lung might undergo relative compression during inflation. The authors conclude that assessments of lung function using Z (rs) combined with the structural alterations inferred from image registration provide unique but complementary information on the mechanical derangements associated with lung injury.