Computational Growth and Remodeling of Abdominal Aortic Aneurysms Constrained by the Spine
Computational Growth and Remodeling of Abdominal Aortic Aneurysms Constrained by the Spine
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DOI：
10.1115/1.4031019
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发表时间：
2015-09-01
影响因子：
1.7
通讯作者：
Baek, Seungik
中科院分区：
文献类型：
--
作者：
Farsad, Mehdi;Zeinali-Davarani, Shahrokh;Baek, Seungik
腹主动脉瘤(AAA)会随着时间的推移而演变，脊柱作为外部屏障，会影响它们的生物力学特性。AAA和脊柱之间的机械相互作用被认为改变了几何结构、壁应力分布和血流，尽管这种相互作用的程度可能取决于AAA的特定配置。在这项研究中，我们使用了一个生长和重塑(G&R)模型，该模型能够跟踪几何结构的变化，从而允许我们通过计算来研究脊柱对AAA进展的影响。基于医学图像的大动脉几何形状与脊柱表面一起构建，并作为点云合并到计算模型中。G&R模拟是由具有不同空间分布的局部弹性蛋白降解发起的。当AAA表面与脊椎表面相遇时，使用惩罚方法来考虑AAA与脊椎的相互作用。模拟结果表明，虽然由于脊椎的约束，AAA壁径向生长在后侧被阻止，但AAA在前侧扩张得更快，导致AAA构型的曲率和不对称性比不包括脊椎的模拟更高。相应地，由于AAA-脊柱接触，AAA壁应力在前侧的外侧、后外侧和肩部区域增加。此外，直径最大的区域会沉积更多的胶原蛋白。我们发现，基于图像的计算G&R模型不仅增强了对腹主动脉的几何形状、壁应力和强度分布的预测，而且还提供了一个框架来解释腹主动脉瘤扩大和脊柱之间的相互作用，以便更好地评估和处理腹主动脉瘤患者的破裂潜力。
Abdominal aortic aneurysms (AAAs) evolve over time, and the vertebral column, which acts as an external barrier, affects their biomechanical properties. Mechanical interaction between AAAs and the spine is believed to alter the geometry, wall stress distribution, and blood flow, although the degree of this interaction may depend on AAAs specific configurations. In this study, we use a growth and remodeling (G&R) model, which is able to trace alterations of the geometry, thus allowing us to computationally investigate the effect of the spine for progression of the AAA. Medical image-based geometry of an aorta is constructed along with the spine surface, which is incorporated into the computational model as a cloud of points. The G&R simulation is initiated by local elastin degradation with different spatial distributions. The AAA-spine interaction is accounted for using a penalty method when the AAA surface meets the spine surface. The simulation results show that, while the radial growth of the AAA wall is prevented on the posterior side due to the spine acting as a constraint, the AAA expands faster on the anterior side, leading to higher curvature and asymmetry in the AAA configuration compared to the simulation excluding the spine. Accordingly, the AAA wall stress increases on the lateral, posterolateral, and the shoulder regions of the anterior side due to the AAA-spine contact. In addition, more collagen is deposited on the regions with a maximum diameter. We show that an image-based computational G&R model not only enhances the prediction of the geometry, wall stress, and strength distributions of AAAs but also provides a framework to account for the interactions between an enlarging AAA and the spine for a better rupture potential assessment and management of AAA patients.