Three-Dimensional Geometrical Characterization of Abdominal Aortic Aneurysms: Image-Based Wall Thickness Distribution
Three-Dimensional Geometrical Characterization of Abdominal Aortic Aneurysms: Image-Based Wall Thickness Distribution
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DOI：
10.1115/1.3127256
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发表时间：
2009-06-01
影响因子：
1.7
通讯作者：
Finol, Ender A.
中科院分区：
文献类型：
--
作者：
Martufi, Giampaolo;Di Martino, Elena S.;Finol, Ender A.
腹主动脉瘤（AAA）破裂风险的临床评估是基于AAA尺寸的量化，通过测量计算机断层扫描（CT）图像的最大直径并估计动脉瘤囊随时间的扩张率。最近的研究结果表明，几何形状和大小，以及局部壁厚可能与这种风险;因此，可靠的无创性基于图像的方法来评估AAA几何形状有可能成为有价值的临床工具。利用现有的CT数据，9个未破裂的人AAA的三维几何重建和定量表征。我们提出并评估了一系列的一维尺寸，二维形状，三维尺寸，三维形状，和二阶曲率为基础的指数，以量化AAA的几何形状，以及几何形状的尺寸匹配的理想梭形动脉瘤和患者特定的正常腹主动脉作为对照。在我们之前的工作中验证的壁厚估计算法，针对从尸体组织模型中获取的离散点测量值进行测试，得出AAA壁厚的平均相对差异为7.8%。任何一个单独的几何指数都不可能是破裂风险的可靠指数或选择性修复的阈值。相反，应考虑完整的几何形状和一组指数的正相关性，以评估破裂的可能性。通过这种定量参数评估，未来的研究可以导向统计分析，将这些参数的数值与动脉瘤破裂或干预（手术或血管内）的风险相关联。虽然这项工作并没有提供直接的洞察几何参数的可能的临床应用，我们相信它提供了必要的基础，为今后的努力，在这个方向。
The clinical assessment of abdominal aortic aneurysm (AAA) rupture risk is based on the quantification of AAA size by measuring its maximum diameter from computed tomography (CT) images and estimating the expansion rate of the aneurysm sac over time. Recent findings have shown that geometrical shape and size, as well as local wall thickness may be related to this risk; thus, reliable noninvasive image-based methods to evaluate AAA geometry have a potential to become valuable clinical tools. Utilizing existing CT data, the three-dimensional geometry of nine unruptured human AAAs was reconstructed and characterized quantitatively. We propose and evaluate a series of 1D size, 2D shape, 3D size, 3D shape, and second-order curvature-based indices to quantify AAA geometry, as well as the geometry of a size-matched idealized fusiform aneurysm and a patient-specific normal abdominal aorta used as controls. The wall thickness estimation algorithm, validated in our previous work, is tested against discrete point measurements taken from a cadaver tissue model, yielding an average relative difference in AAA wall thickness of 7.8%. It is unlikely that any one of the proposed geometrical indices alone would be a reliable index of rupture risk or a threshold for elective repair. Rather, the complete geometry and a positive correlation of a set of indices should be considered to assess the potential for rupture. With this quantitative parameter assessment, future research can be directed toward statistical analyses correlating the numerical values of these parameters with the risk of aneurysm rupture or intervention (surgical or endovascular). While this work does not provide direct insight into the possible clinical use of the geometric parameters, we believe it provides the foundation necessary for future efforts in that direction.