Computational fluid dynamics analysis of upper airway reconstructed from magnetic resonance imaging data
Computational fluid dynamics analysis of upper airway reconstructed from magnetic resonance imaging data
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DOI：
10.1177/000348940811700411
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发表时间：
2008-04-01
影响因子：
1.4
通讯作者：
Kalra, Maninder
中科院分区：
文献类型：
--
作者：
Mihaescu, Mihal;Murugappan, Shanmugam;Kalra, Maninder
目的：对阻塞性睡眠呼吸暂停患者的精确上呼吸道模型进行流动计算，计算模型内的速度、静压和壁面剪应力分布。方法：根据横断面磁共振图像确定气道边界的笛卡尔坐标，构建上呼吸道的三维计算模型。然后在流畅的商业软件框架内进行流动模拟。在吸气过程中，模拟了四种不同的流动状态，假设为稳态状态。从速度、静压和壁面剪应力分布的角度对结果进行分析。结果：观察到最大轴向速度出现在横截面面积最小的位置(腭咽后)，从而导致壁面静压水平最低。壁面剪应力最大的位置在同一位置。结论：我们的结果表明，通过改变流动特性，导致流速增加和静压降低，气道狭窄的存在本身可以增加气道的溃散性。此外，管壁切应力对气道壁的影响可能是阻塞性睡眠呼吸暂停的严重程度随时间进展的重要因素。
Objectives: We performed flow computations on an accurate upper airway model in a patient with obstructive sleep apnea and computed the velocity, static pressure, and wall shear stress distribution in the model.Methods: Cartesian coordinates for airway boundaries were determined from cross-sectional magnetic resonance images, and a 3-dimensional computational model of the upper airway was constructed. Flow simulations were then performed within a FLUENT commercial software framework. Four different flow conditions were simulated during inspiration, assuming the steady-state condition. The results were analyzed from the perspectives of velocity, static pressure, and wall shear stress distribution.Results: We observed that the highest axial velocity was at the site of minimum cross-sectional area (retropalatal pharynx) resulting in the lowest level of wall static pressure. The highest wall shear stresses were at the same location. The pressure drop was significantly larger for higher flow rates than for lower flow rates.Conclusions: Our results indicate that the presence of airway narrowing, through change in the flow characteristics that result in increased flow velocity and reduced static pressure, can itself increase airway collapsibility. Additionally, the effects of wall shear stress on airway walls may be an important factor in the progression over time of the severity of obstructive sleep apnea.