Beyond fusiform and saccular: A novel quantitative tortuosity index may help classify aneurysm shape and predict aneurysm rupture potential
Beyond fusiform and saccular: A novel quantitative tortuosity index may help classify aneurysm shape and predict aneurysm rupture potential
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DOI：
10.1016/j.avsg.2007.09.004
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发表时间：
2008-01-01
影响因子：
1.5
通讯作者：
Gusberg, Richard J.
中科院分区：
文献类型：
--
作者：
Pappu, Suguna;Dardik, Alan;Gusberg, Richard J.
虽然囊状腹主动脉瘤（AAA）被认为比梭形动脉瘤更容易破裂，但由于无法定量定义主动脉的三维形状，验证该观察结果的尝试受到限制。定量三维形状模型可以区分形状类别，并最终有助于识别有破裂风险的动脉瘤。根据15例小动脉瘤（最大横向直径< 5.5 cm）患者的计算机断层扫描（CT）图像生成AAA的三维管腔表面数据。中心线被用来构建一个形状分类的基础上的正投影的中心线围绕其中心轴。将个体偏差的程度和方向量化为投影平面上的面积，以创建形状分类。层次聚类分析被用来验证不同的形状类。根据中心线投影计算迂曲指数。AAA形状计算为迂曲指数，并分为不同的最小或增加的三维迂曲度类别。血栓可以改变动脉瘤的迂曲指数或形状分类。在几例连续CT扫描的患者中，迂曲度指数随时间变化，并与破裂相关;在3例破裂的AAA中，平均迂曲度增加29%，而平均横径增加3.3%。扩展AAA形成特定的、可量化的形状，其可以表示为可能与其自然历史相关的定量迂曲度指数。该形状模型的三维特征为最大横径提供了一种新的和潜在的临床相关辅助手段。需要更大规模的研究来将迂曲指数与有限元模型和预测动脉瘤破裂的能力相关联。
While saccular abdominal aortic aneurysms (AAAs) are thought to be more prone to rupture than fusiform aneurysms, attempts to validate this observation have been limited by the inability to quantitatively define the three-dimensional shape of an aorta. A quantitative three-dimensional shape model may distinguish among shape classes and ultimately be useful in identifying aneurysms at risk for rupture. Three-dimensional luminal surface data of AAAs were generated from computed tomographic (CT) images of 15 patients with small aneurysms (< 5.5 cm maximal transverse diameter). The centerline was used to construct a shape classification based upon the orthographic projection of the centerline about its central axis. The extent and direction of the individual deviations were quantified as areas on the plane of projection to create a shape classification. Hierarchical cluster analysis was used to verify distinct shape classes. A tortuosity index was calculated as a function of the centerline projection. AAA shape was calculated as a tortuosity index and classified into distinct classes of minimal or increased three-dimensional tortuosity. Thrombus could change the tortuosity index or shape classification of an aneurysm. In several patients with serial CT scans, the tortuosity index changed over time and was correlated with rupture; in three AAAs that ruptured the mean tortuosity increased 29% whereas the mean transverse diameter increased 3.3%. Expanding AAAs develop specific, quantifiable shapes that can be expressed as a quantitative tortuosity index that may be relevant to their natural history. The three-dimensional features of this shape model provide a novel and potentially clinically relevant adjunct to maximal transverse diameter. Larger studies are needed to correlate the tortuosity index with finite element models and the ability to predict aneurysm rupture.