Millán R D, Dempere-Marco L, Pozo J M, Cebral J R, Frangi A F
Computational Imaging Laboratory (CILab), Pompeu Fabra University, 8-E08003 Barcelona, Spain.
IEEE Trans Med Imaging. 2007 Sep;26(9):1270-82. doi: 10.1109/TMI.2007.901008.
Rupture of intracranial saccular aneurysms is the most common cause of spontaneous subarachnoid hemorrhage, which has significant morbidity and mortality. Although there is still controversy regarding the decision on which unruptured aneurysms should be treated, this is based primarily on their size. Nonetheless, many large lesions do not rupture whereas some small ones do. It is commonly accepted that hemodynamical factors are important to better understand the natural history of cerebral aneurysms. However, it might not always be practical to carry out a detailed computational analysis of such factors if a prompt assessment is required. Since shape is likely to be dependent on the balance between hemodynamic forces and the aneurysmal surrounding environment, an appropriate morphological 3-D characterization is likely to provide a practical surrogate to quickly evaluate the risk of rupture. In this paper, an efficient and novel methodology for 3-D shape characterization of cerebral aneurysms is described. The aneurysms are isolated by taking into account a portion of their adjacent vessels. Two methods to characterize the morphology of the aneurysms models using moment invariants have been considered: geometrical moment invariants (GMI) and Zernike moment invariants (ZMI). The results have been validated in a database containing 53 patients with a total of 31 ruptured aneurysms and 24 unruptured aneurysms. It has been found that ZMI indices are more robust than GMI, and seem to provide a reliable way to discriminate between ruptured and unruptured aneurysms. Correct rupture prediction rates of approximately equal to 80% were achieved in contrast to 66% that is found when the aspect ratio index is considered.
颅内囊状动脉瘤破裂是自发性蛛网膜下腔出血最常见的原因，具有较高的发病率和死亡率。尽管对于哪些未破裂动脉瘤应接受治疗的决策仍存在争议，但其主要依据是动脉瘤的大小。然而，许多大的动脉瘤并未破裂，而一些小的却破裂了。人们普遍认为血流动力学因素对于更好地理解脑动脉瘤的自然病史很重要。然而，如果需要快速评估，对这些因素进行详细的计算分析可能并不总是可行的。由于形状可能取决于血流动力学力与动脉瘤周围环境之间的平衡，合适的形态学三维表征可能会提供一种实用的替代方法来快速评估破裂风险。本文描述了一种用于脑动脉瘤三维形状表征的高效新颖方法。通过考虑动脉瘤相邻血管的一部分来分离动脉瘤。考虑了两种使用矩不变量来表征动脉瘤模型形态的方法：几何矩不变量（GMI）和泽尼克矩不变量（ZMI）。结果在一个包含53例患者、共31个破裂动脉瘤和24个未破裂动脉瘤的数据库中得到了验证。研究发现，ZMI指数比GMI更稳健，似乎提供了一种区分破裂和未破裂动脉瘤的可靠方法。与考虑长宽比指数时发现的66%相比，正确的破裂预测率约达到80%。
