基于CT的颅内动脉瘤数值模型优化及破裂几何因素分析

发布时间：2018-06-11 13:23

本文选题：CT + 弹性壁　；参考：《新疆大学》2017年硕士论文

【摘要】：目的构建颅内动脉瘤的数值模型,并对数值模型进行优化处理,以期为后续支架设计以及支架介入实验提供良好的模型参数。分析动脉瘤破裂、出血的几何外观因素,为临床上动脉瘤破裂的风险评判提供一定的参数标准。方法利用三维CT技术建立患者脑动脉瘤三维模型,然后结合计算流体力学软件ANSYS CFX15.0构建动脉瘤数值模型。对比分析不同条件下,如刚性壁和弹性壁、瘤体壁厚与动脉血管壁厚一致与否、牛顿和非牛顿流体、动脉血管入口与出口长度不一、不同杨氏模量情况下瘤腔内血流场变化情况。对于动脉瘤破裂的几何因素,选取83例动脉瘤患者CT数据,建立三维模型,测量模型的几何外观参数。运用统计学软件spss23.0,对破裂动脉瘤与未破裂动脉瘤几何尺寸进行统计分析。结果弹性壁模型相较于刚性壁,刚性壁最大变形量约占管径13%,同比下弹性壁变形量约占管径7.5%。刚性壁变形量约是弹性壁的2.4倍。牛顿与非牛顿模型血流场参数相差不大,最大约为2.19%。动脉瘤璧与动脉血管壁厚度分开定义与不分开定义的模型,瘤体壁面变形差异较大,约为43%。动脉血管壁的变形量随着杨氏模量的增加而减小。动脉瘤出口长度不变时,入口长度过短时,瘤腔内涡流不明显,随着入口长度的增加涡流现象加剧,到最后稳定在一定长度内。入口长度保持不变,出口长度不一时,两组模型流场差异不大。对破裂动脉瘤与未破裂动脉瘤几何外观尺寸统计发现,AR,最大瘤宽、射出角、以及载瘤动脉夹角P0.05,有统计学意义,其他参数均无统计学意义。对AR、瘤宽、射出角和载瘤动脉夹角进行受试者工作特性曲线,简称ROC曲线分析,得出四者的最佳诊断界值分别为1.4835(灵敏度80%,特异度41.9%),5.3(灵敏度100%,特异度18.6%)、34.5(灵敏度75%,特异度37.2%)。载瘤动脉夹角ROC曲线分析,曲线下区域面积即AUC为0.2380.5,不具有诊断意义。最终得出瘤宽、AR、射出角三者诊断效能为瘤宽AR射出角。
[Abstract]:Objective to construct a numerical model of intracranial aneurysm and optimize the model so as to provide a good model parameter for the subsequent stent design and stent intervention experiment. The geometric appearance factors of ruptured aneurysm and hemorrhage were analyzed to provide a certain parameter standard for evaluating the risk of ruptured aneurysm clinically. Methods Three-dimensional CT technique was used to establish a three-dimensional model of cerebral aneurysm, and then a numerical model of aneurysm was constructed with ANSYS CFX 15.0 software. Under different conditions, such as rigid wall and elastic wall, the thickness of tumor wall is consistent with the thickness of arterial vessel wall, Newton and non-Newtonian fluid, the length of artery inlet and outlet are different. Changes of blood flow field in tumor cavity under different Young's modulus. For the geometric factors of aneurysm rupture, the CT data of 83 patients with aneurysm were selected, the 3D model was established and the geometric appearance parameters of the model were measured. The geometric dimensions of ruptured and unruptured aneurysms were analyzed by SPSS 23.0. Results compared with the rigid wall, the maximum deformation of the rigid wall is about 13% of the diameter of the tube, and the deformation of the elastic wall is about 7.5% of the diameter of the tube. The deformation of rigid wall is about 2.4 times that of elastic wall. The parameters of blood flow field of Newtonian model and non-Newtonian model are similar, the maximum is about 2.19. The wall deformation of the aneurysm is different from that of the thickness of the artery wall, which is about 43%. The deformation of arterial wall decreased with the increase of Young's modulus. When the length of aneurysm outlet is constant, the eddy current is not obvious when the inlet length is too short, and the eddy current phenomenon intensifies with the increase of inlet length, and is stabilized within a certain length at last. When the inlet length remains constant and the outlet length is different, there is little difference between the two groups. The geometric appearance and size of ruptured aneurysms and unruptured aneurysms were statistically significant, but no statistical significance was found in other parameters, such as the maximum width of aneurysm, the angle of ejection, and the angle of aneurysm carrier artery (P0.05). The operating characteristic curves (ROC curve) of ARs, tumor width, ejection angle and angle of aneurysm carrying artery were analyzed. The results showed that the best diagnostic threshold of the four patients was 1.4835 (sensitivity 80, specificity 41.9) 5.3 (sensitivity 100, specificity 18.60.34. 5) (sensitivity 75, specificity 37.2). The analysis of the ROC curve showed that the area under the curve was 0.2380.5, which had no diagnostic significance. Finally, the diagnostic efficacy of the tumor width ARs and the ejection angle is the tumor width AR ejection angle.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R743;R816.1

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