Coupling of fluid and elastic models for biomechanical simulations of brain deformations using FEM
Coupling of fluid and elastic models for biomechanical simulations of brain deformations using FEM
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DOI：
10.1016/s1361-8415(02)00059-2
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发表时间：
2002-12-01
影响因子：
10.9
通讯作者：
Stiehl, HS
中科院分区：
文献类型：
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作者：
Hagemann, A;Rohr, K;Stiehl, HS
为了提高图像引导神经外科手术的准确性，已经开发了不同的生物力学模型，以针对术中变化（如脑移位或肿瘤切除）校正术前图像。所有现有的生物力学模型通过使用适当的边界条件或通过空间变化的材料参数值来模拟不同的解剖结构，同时假设所有解剖结构具有相同的物理模型。一般来说，这会导致物理上难以置信的结果，特别是在相邻的弹性和流体结构的情况下。因此，我们提出了一种新的方法，允许耦合不同的物理模型。在我们的例子中，我们模拟刚性，弹性和流体区域使用适当的物理描述，为每种材料，即无论是Navier方程或斯托克斯方程。为了解决由此产生的微分方程，我们推导出一个线性矩阵系统的每个区域，通过应用有限元法（FEM）。然后，将线性矩阵系统连接在一起，最终得到一个整体线性矩阵系统。我们的新方法已经过测试，并使用合成图像和断层图像与纯线性弹性模型进行了比较。从我们的实验中可以看出，与纯线性弹性模型相比，刚性，弹性和流体区域的综合处理提高了预测变形结果的物理可解释性。(C)2002 Elsevier Science B.V.保留所有权利。
In order to improve the accuracy of image-guided neurosurgery, different biomechanical models have been developed to correct preoperative images with respect to intraoperative changes like brain shift or tumor resection. All existing biomechanical models simulate different anatomical structures by using either appropriate boundary conditions or by spatially varying material parameter values, while assuming the same physical model for all anatomical structures. In general, this leads to physically implausible results, especially in the case of adjacent elastic and fluid structures. Therefore, we propose a new approach which allows to couple different physical models. In our case, we simulate rigid, elastic and fluid regions by using the appropriate physical description for each material, namely either the Navier equation or the Stokes equation. To solve the resulting differential equations, we derive a linear matrix system for each region by applying the finite element method (FEM). Thereafter, the linear matrix systems are linked together, ending up with one overall linear matrix system. Our new approach has been tested and compared to a purely linear elastic model using synthetic as well as tomographic images. It turns out from our experiments, that the integrated treatment of rigid, elastic and fluid regions improves the physical plausibility of the predicted deformation results as compared to a purely linear elastic model. (C) 2002 Elsevier Science B.V. All rights reserved.