Heterogeneous mechanics of the mouse pulmonary arterial network

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• 作者：Pilhwa Lee ; Brian E. Carlson ; Naomi Chesler…
• 关键词：Arterial blood flow ; Vessel mechanics ; Heterogeneity ; Pulmonary arterial network ; Pressure–radius relationship ; Wave intensity analysis
• 刊名：Biomechanics and Modeling in Mechanobiology
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：15
• 期：5
• 页码：1245-1261
• 全文大小：2,900 KB
• 刊物类别：Engineering
• 刊物主题：Theoretical and Applied Mechanics
  Biomedical Engineering
  Mechanics
  Biophysics and Biomedical Physics
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1617-7940
• 卷排序：15

文摘

Individualized modeling and simulation of blood flow mechanics find applications in both animal research and patient care. Individual animal or patient models for blood vessel mechanics are based on combining measured vascular geometry with a fluid structure model coupling formulations describing dynamics of the fluid and mechanics of the wall. For example, one-dimensional fluid flow modeling requires a constitutive law relating vessel cross-sectional deformation to pressure in the lumen. To investigate means of identifying appropriate constitutive relationships, an automated segmentation algorithm was applied to micro-computerized tomography images from a mouse lung obtained at four different static pressures to identify the static pressure–radius relationship for four generations of vessels in the pulmonary arterial network. A shape-fitting function was parameterized for each vessel in the network to characterize the nonlinear and heterogeneous nature of vessel distensibility in the pulmonary arteries. These data on morphometric and mechanical properties were used to simulate pressure and flow velocity propagation in the network using one-dimensional representations of fluid and vessel wall mechanics. Moreover, wave intensity analysis was used to study effects of wall mechanics on generation and propagation of pressure wave reflections. Simulations were conducted to investigate the role of linear versus nonlinear formulations of wall elasticity and homogeneous versus heterogeneous treatments of vessel wall properties. Accounting for heterogeneity, by parameterizing the pressure/distention equation of state individually for each vessel segment, was found to have little effect on the predicted pressure profiles and wave propagation compared to a homogeneous parameterization based on average behavior. However, substantially different results were obtained using a linear elastic thin-shell model than were obtained using a nonlinear model that has a more physiologically realistic pressure versus radius relationship.