A simple, effective and clinically applicable method to compute abdominal aortic aneurysm wall stress
A simple, effective and clinically applicable method to compute abdominal aortic aneurysm wall stress
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DOI：
10.1016/j.jmbbm.2015.07.029
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发表时间：
2016-05-01
影响因子：
3.9
通讯作者：
Doyle, Barry
中科院分区：
文献类型：
--
作者：
Joldes, Grand Roman;Miller, Karol;Doyle, Barry
腹主动脉瘤（AAA）是主动脉下部区域永久性且不可逆的扩张。这是一种无症状的病症，如果不及时治疗，可能会扩大到破裂的程度。从力学上来说，当局部壁应力超过局部壁强度时，就会发生动脉破裂。因此，希望能够快速、可靠地非侵入性地估计给定患者的 AAA 壁应力。在本文中，我们提出了一种全新的方法来计算 AAA 内的壁张力（即，应力结果等于与壁相切的应力在壁厚度上的积分），该方法依赖于简单的线性弹性有限元计算，可以在临床环境中使用最简单的计算硬件即时执行。作为计算的输入，我们仅使用临床上容易获得的信息：体内动脉瘤的形状（如计算机断层扫描（CT）扫描所示）和血压。我们证明，用所提出的方法计算的张力场与使用非常复杂、最先进的非线性逆过程获得的张力场非常吻合。使用同一患者的磁共振（MR）图像，我们可以近似测量局部壁厚并计算局部壁应力。这种简单方法真正令人兴奋的是，不需要任何有关材料参数的信息；它是一种简单的方法。这支持了患者特定建模 (PSM) 的开发和使用，其中材料数据的不确定性被认为是一个关键限制。本文演示的方法适用于已知系统负载和负载几何形状的其他生物力学领域。 (C) 2015 Elsevier Ltd. 保留所有权利。
Abdominal aortic aneurysm (AAA) is a permanent and irreversible dilation of the lower region of the aorta. It is a symptomless condition that if left untreated can expand to the point of rupture. Mechanically-speaking, rupture of an artery occurs when the local wall stress exceeds the local wall strength. It is therefore desirable to be able to non-invasively estimate the AAA wall stress for a given patient, quickly and reliably.In this paper we present an entirely new approach to computing the wall tension (Le. the stress resultant equal to the integral of the stresses tangent to the wall over the wall thickness) within an AAA that relies on trivial linear elastic finite element computations, which can be performed instantaneously in the clinical environment on the simplest computing hardware. As an input to our calculations we only use information readily available in the clinic: the shape of the aneurysm in-vivo, as seen on a computed tomography (CT) scan, and blood pressure. We demonstrate that tension fields computed with the proposed approach agree well with those obtained using very sophisticated, state-of-the-art non-linear inverse procedures. Using magnetic resonance (MR) images of the same patient, we can approximately measure the local wall thickness and calculate the local wall stress. What is truly exciting about this simple approach is that one does not need any information on material parameters; this supports the development and use of patient-specific modelling (PSM), where uncertainty in material data is recognised as a key limitation.The methods demonstrated in this paper are applicable to other areas of biomechanics where the loads and loaded geometry of the system are known. (C) 2015 Elsevier Ltd. All rights reserved.