A search in Scopus within "Article title, Abstract, Keywords" unveils 2,444 documents focused on the biomechanics of Abdominal Aortic Aneurysm (AAA), mostly on AAA wall stress. Only 24 documents investigated AAA kinematics, an important topic that could potentially offer insights into the biomechanics of AAA. In this paper, we present an image-based approach for patient-specific, in vivo, and non-invasive AAA kinematic analysis using patient's time-resolved 3D computed tomography angiography (4D CTA) images. Our approach relies on regularized deformable image registration for estimating wall displacement, estimation of the local wall strain as the ratio of its normal displacement to its local radius of curvature, and local surface fitting with non-deterministic outlier detection for estimating the wall radius of curvature. We verified our approach against synthetic ground truth image data created by warping a 3D CTA image of AAA using a realistic displacement field obtained from a finite element biomechanical model. We applied our approach to assess AAA wall displacements and strains in ten patients. Our kinematic analysis results indicated that the 99th percentile of circumferential wall strain, among all patients, ranged from 3.16% to 7.31%, with an average of 5.36% and a standard deviation of 1.28%.

翻译：在Scopus数据库中，以“文章标题、摘要、关键词”为范围进行检索，可发现2,444篇专注于腹主动脉瘤（AAA）生物力学研究的文献，其中大部分集中于AAA壁应力分析。仅有24篇文献研究了AAA运动学，这是一个重要的研究方向，可能为理解AAA的生物力学机制提供新的视角。本文提出了一种基于影像的、针对患者个体化的、在体的、非侵入性的AAA运动学分析方法，该方法利用患者的时间分辨三维计算机断层扫描血管造影（4D CTA）图像。我们的方法依赖于正则化的可变形图像配准来估计血管壁位移，通过计算血管壁法向位移与其局部曲率半径的比值来估计局部壁应变，并采用带有非确定性异常值检测的局部曲面拟合来估计血管壁的曲率半径。我们使用通过有限元生物力学模型获得的真实位移场对AAA的3D CTA图像进行形变，生成了合成的基准真实图像数据，并以此验证了我们的方法。我们将该方法应用于评估十名患者的AAA血管壁位移和应变。我们的运动学分析结果表明，在所有患者中，周向壁应变的第99百分位数范围在3.16%至7.31%之间，平均值为5.36%，标准差为1.28%。