Patient-specific initial wall stress in abdominal aortic aneurysms with a backward incremental method
Patient-specific initial wall stress in abdominal aortic aneurysms with a backward incremental method
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DOI：
10.1016/j.jbiomech.2006.04.019
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发表时间：
2007-01-01
影响因子：
2.4
通讯作者：
van de Vosse, F. N.
中科院分区：
文献类型：
--
作者：
de Putter, S.;Wolters, B. J. B. M.;van de Vosse, F. N.
患者特异性腹主动脉瘤壁应力模拟可能提供比目前使用的最大横径更好的手术干预标准。在这些模拟中，通常的做法是通过将完全收缩压直接应用于医学图像中出现的动脉瘤几何形状来计算峰值壁应力。由于这种方法没有考虑到测量的几何形状已经经历了相当大的负荷，因此可能导致不正确的收缩期动脉瘤形状。我们已经开发了一种方法来计算壁应力在真实舒张几何在给定的压力与向后增量方法。用新胡克材料定律对几个简单的试验问题进行了评价。结果表明，在已知加载几何形状和加载载荷的情况下，该方法可以预测出一个未加载的结构。合并初始舒张应力的效果已通过使用心脏触发mr获得的三种患者特定几何形状来评估。比较表明，常用的方法导致不现实的平滑收缩几何形状，因此提供了对峰值壁应力的低估。我们的后向增量建模方法克服了这些问题，并提供了一个更合理的收缩期动脉瘤体积估计和一个明显不同的峰值壁应力估计。将该方法应用于专门针对腹主动脉瘤提出的更复杂的物质规律时，可以观察到类似的效果，并得出相同的结论。(c) 2006 Elsevier Ltd.版权所有。
Patient-specific wall stress simulations on abdominal aortic aneurysms may provide a better criterion for surgical intervention than the currently used maximum transverse diameter. In these simulations, it is common practice to compute the peak wall stress by applying the full systolic pressure directly on the aneurysm geometry as it appears in medical images. Since this approach does not account for the fact that the measured geometry is already experiencing a substantial load, it may lead to an incorrect systolic aneurysm shape. We have developed an approach to compute the wall stress on the true diastolic geometry at a given pressure with a backward incremental method. The method has been evaluated with a neo-Hookean material law for several simple test problems. The results show that the method can predict an unloaded configuration if the loaded geometry and the load applied are known. The effect of incorporating the initial diastolic stress has been assessed by using three patient-specific geometries acquired with cardiac triggered MR. The comparison shows that the commonly used approach leads to an unrealistically smooth systolic geometry and therefore provides an underestimation for the peak wall stress. Our backward incremental modelling approach overcomes these issues and provides a more plausible estimate for the systolic aneurysm volume and a significantly different estimate for the peak wall stress. When the approach is applied with a more complex material law which has been proposed specifically for abdominal aortic aneurysm similar effects are observed and the same conclusion can be drawn. (c) 2006 Elsevier Ltd. All rights reserved.