Department of Solid Mechanics, School of Engineering Sciences, Royal Institute of Technology, Stockholm, Sweden.
IEEE Trans Med Imaging. 2010 Apr;29(4):1022-8. doi: 10.1109/TMI.2009.2039579. Epub 2010 Mar 22.
Evaluating rupture risk of abdominal aortic aneurysms is critically important in reducing related mortality without unnecessarily increasing the rate of elective repair. According to the current clinical practice aneurysm rupture risk is (mainly) estimated from its maximum diameter and/or expansion rate; an approach motivated from statistics but known to fail often in individuals. In contrast, recent research demonstrated that patient specific biomechanical simulations can provide more reliable diagnostic parameters, however current structural model development is cumbersome and time consuming. This paper used 2D and 3D deformable models to reconstruct aneurysms from computerized tomography angiography data with minimal user interactions. In particular, formulations of frames and shells, as known from structural mechanics, were used to define deformable modes, which in turn allowed a direct mechanical interpretation of the applied set of reconstruction parameters. Likewise, a parallel finite element implementation of the models allows the segmentation of clinical cases on standard personal computers within a few minutes. The particular topology of the applied 3D deformable models supports a fast and simple hexahedral-dominated meshing of the arising generally polyhedral domain. The variability of the derived segmentations (luminal: 0.50(SD 0.19) mm; exterior 0.89(SD 0.45) mm) with respect to large variations in elastic properties of the deformable models was in the range of the differences between manual segmentations as performed by experts (luminal: 0.57(SD 0.24) mm; exterior: 0.77(SD 0.58) mm), and was particularly independent from the algorithm's initialization. The proposed interaction of deformable models and mesh generation defines finite element meshes suitable to perform accurate and efficient structural analysis of the aneurysm using mixed finite element formulations.
评估腹主动脉瘤破裂的风险对于降低相关死亡率至关重要，同时也不必不必要地增加择期修复的比率。根据目前的临床实践，动脉瘤破裂的风险主要是根据其最大直径和/或扩张率来估计的；这种方法源于统计学，但在个体中经常失效。相比之下，最近的研究表明，患者特定的生物力学模拟可以提供更可靠的诊断参数，然而，目前的结构模型开发既繁琐又耗时。本文使用 2D 和 3D 可变形模型，通过最小的用户交互从计算机断层血管造影数据中重建动脉瘤。特别是，从结构力学中已知的框架和壳的公式被用来定义可变形模式，这反过来又允许对应用的一组重建参数进行直接的力学解释。同样，模型的并行有限元实现允许在几分钟内在标准个人计算机上对临床病例进行分割。所应用的 3D 可变形模型的特殊拓扑结构支持快速而简单的基于六面体的网格划分，通常适用于出现的多面体域。从可变形模型的弹性性质的大变化中得出的分割的可变性（管腔：0.50（SD 0.19）mm；外部：0.89（SD 0.45）mm）与专家进行的手动分割之间的差异在范围内（管腔：0.57（SD 0.24）mm；外部：0.77（SD 0.58）mm），并且特别独立于算法的初始化。可变形模型和网格生成的交互定义了有限元网格，适合使用混合有限元公式对动脉瘤进行准确有效的结构分析。
