Finite-difference simulations of 3He diffusion in 3D alveolar ducts:: Comparison with the "cylinder model"
Finite-difference simulations of 3He diffusion in 3D alveolar ducts:: Comparison with the "cylinder model"
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DOI：
10.1002/mrm.20213
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发表时间：
2004-10-01
影响因子：
3.3
通讯作者：
Wild, JM
中科院分区：
文献类型：
--
作者：
Fichele, S;Paley, MNJ;Wild, JM
随时间变化的肺中He-3扩散的测量可以提供一种准确的方法来量化肺泡长度尺度和疾病的进展，如肺气肿。然而，表观扩散系数（ADC）提出了一个复杂的问题，建模和解析解决。在这里，有限差分法被用来模拟扩散的三维肺泡管。结果进行了比较，唯一可用的分析模型-“圆柱体模型”-从它是可能的估计平均半径的肺泡管从体内数据。从模拟中观察到的数据的趋势被认为是同意以及与圆柱体模型。然而，圆柱模型总是高估了模拟肺泡管的平均半径。模拟还表明，纵向ADC（沿着肺泡管）的测量应该对早期肺气肿变化敏感，而测量的半径应该远不敏感。(C)2004 Wiley-Liss，Inc.
Time-dependent measurements of He-3 diffusion in the lung could provide an accurate method to quantify alveolar length scales and the progression of diseases such as emphysema. However, the apparent diffusion coefficient (ADC) presents a complex problem to model and solve analytically. Here, finite-difference methods were used to simulate diffusion in 3D alveolar ducts. The results were compared to the only available analytical model-the "cylinder model"-from which it is possible to estimate the average radii of the alveolar ducts from in vivo data. The trend in data observed from simulations was found to agree well with the cylinder model. However, the cylinder model always overestimated the average radii of the simulated alveolar ducts. The simulations also demonstrated that the measurement of the longitudinal ADC (along the alveolar ducts) should be sensitive to early emphysematous changes, whereas the measured radii should be far less sensitive. (C) 2004 Wiley-Liss, Inc.