基于CT血管成像的个体化自体动静脉内瘘三维数值模型

Preliminary study of a three-dimensional numerical model of individualized autologous arteriovenous fistula based on CT angiography

目的:探讨个体化自体动静脉内瘘(AVF)三维数值模型构建的可行性。方法:采用MIMICS软件读取自体AVF患者CT血管造影时DICOM格式的原始数据,运用阈值分割和手动分割相结合的方式进行感兴趣区的三维重建。并用CFX软件进行模型的数值仿真,分析与自体AVF功能不全相关的血流动力学参数。结果:成功构建了个体化自体AVF的三维有限元模型,可直观显示内瘘区的血流分布特点。流速最大在内瘘吻合口动脉端;进入静脉端瘤体内的主血流一部分沿瘤体壁向远处发展成涡流后达出口,另一部分朝瘤体中心形成较小的涡流后再达出口;次血流则直接沿着瘤壁到出口。结论:基于相对无创的CTA影像数据构建的真实可视化的自体AVF三维数值模型相比理想化的实验模型不仅可行、可靠,而且更加有针对性,可以形象地评估内瘘区血流动力学情况,有助于早期对患者进行个体化干预。

Objective:To explore the feasibility of establishing a three-dimensional numerical model of individualized autogenous arteriovenous fistula.Methods:MIMICS software was used to read the raw data in DICOM format during CT angiography of autologous arteriovenous fistula patients.A combination of threshold segmentation and manual segmentation was used for the 3D reconstruction of the region of interest.The numerical simulation of the model was performed with CFX software to analyze the hemodynamic parameters associated with autologous arteriovenous fistula dysfunction.Results:The three-dimensional finite element model of individualized autologous arteriovenous fistula was reconstructed successfully,which could visualize the blood flow distribution characteristics of the fistula area.The largest flow velocity was at the arterial end of the internal fistula.Part of the main blood flow entering the tumor body at the vein end developed into a vortex along the tumor wall,and the other part of blood flow forms a smaller vortex toward the center of the tumor before reaching the outlet.The secondary blood flow was along the tumor wall directly to the outlet.Conclusion:Compared with idealized experimental models,a realistic visualized 3D numerical model of autologous arteriovenous fistula based on relatively non-invasive CTA image data is not only feasible and reliable,but also more specific,which can visually assess the hemodynamic status of the fistula area and facilitate early individualized intervention.