颅内动脉瘤伴开窗畸形血流动力学数值模拟分析的初步研究

目的探讨构建颅内动脉瘤（IA）伴开窗畸形三维数字化模型的可行性，并建立三维有限元模型。方法选取1例前交通动脉瘤伴开窗畸形的急诊患者为研究对象，利用GELightspeed64排螺旋CT获得患者颅脑CT原始数据。应用Mimics软件连续读入DICOM格式的颅脑CT原始数据，采用阈值分割与手动分割相结合的图像处理方法得到最感兴趣部位，并选择3D重建按钮进行三维重建。再应用Geomagicstudio软件以“抽壳法”对三维重建模型的表面三角面片形态网格和血管壁截面作进一步优化处理，再现血管壁的真实形态。优化后的三维数字化模型以标准模板库（STL）格式保存并输出。应用CFX软件进行三维刚性模型的数值仿真，并分析与动脉瘤生长及破裂相关的血流动力学参数。结果联合应用Mimics软件和Geomagicstudio软件首次成功建立了IA伴开窗畸形的三维数字化模型。模型进一步生成三维有限元模型，并作了相关血流动力学分析，形象地显示了瘤中各区域动脉瘤壁的壁剪切力分布情况。在血流冲击瘤颈处，壁剪切力最大，瘤体次之；在瘤顶处剪切力最小；在开窗处，壁剪切力明显增大。结论借助可靠的CT成像技术和优化的建模方法，联合应用Mimics软件和Geomagicstudio软件可以成功建立IA伴开窗畸形的三维数字化模型，并分析动脉瘤各个区域和开窗处的血流动力学参数。

Three dimensional digital model of hemodynamics in intracranial aneurysms with fenestration

Objective To construction a three-dimensional digital model of hemodynamics in intracranial aneurysm with fenestration. Methods An emergent patient of anterior communicating artery aneurysm with fenestration admitted in the First Affiliated Hospital of Wenzhou Medical University was selected as the study object. The patient underwent brain CT scan with GE Lightspeed 64-channel multidetector CT scanner. Mimics software was used to read consistent CT raw data of DICOM format directly and the three-dimensional function was used to reconstruct the model by threshold segmentation combined with manual segmentation method and to obtain the most important region of interest. Then Geomagic studio software was used to further optimize surface meshes with triangle patch shape and sections of vessel wall of the three-dimensional reconstruction model; in particular, the ''Shell Method'' was utilized for optimizing sections of vessel wall in order to reflect the real nature of blood vessel. The optimized three-dimensional digital model was stored and sent out by STL format, and then the hemodynamic parameters related to the growth and rupture of aneurysms were analyzed. Results The three-dimensional digital model of intracranial aneurysm with fenestration was reconstructed successfully. The further three-dimensional finite element model and related hemodynamics were analyzed. The wall shear stress was given in the distribution of various parts of aneurysm. In the window areas, the wall shear stress increased considerably. Conclusion The three-dimensional digital model of intracranial aneurysm with fenestration has been reconstructed successfully, with this model the hemodynamics of each region and the window of the aneurysm can be analyzed.