人中耳及外耳道有限元模型的建立及验证

发布时间：2018-04-03 10:28

本文选题：有限元模型　切入点：中耳　出处：《复旦大学》2011年硕士论文

【摘要】：目的：本研究通过Micro-CT扫描新鲜人的颞骨标本,获取不包括耳廓,完整外耳道、中耳、内耳结构的断层图片数据。以精确的断层图片为数据蓝本,建立几何模型、网格模型及有限元模型并加以验证。正确的有限元模型可用于模拟正常及病变外耳、中耳、内耳结构,模拟异常及可行的修复措施,为临床手术的改进提供理论依据。方法：自复旦大学上海医学院解剖教研室取得人类新鲜尸头一枚,使用耳内镜确认其外耳道及鼓膜正常完整,解剖尸头,游离两侧颞骨。在手术显微镜下使用耳科电钻修剪标本,修剪后的颞骨标本应包括完整的内耳、中耳腔、乳突气房及外耳道等结构,并能稳定的垂直固定于扫描舱。行Micro-CT扫描时使标本外耳道口端朝下,设置为高精度扫描。扫描后分别行13微米及45微米重建,两套数据都以DICOM格式保存。将数据导入MIMIC软件,选择显示窗位及窗宽以求最佳显示效果,从三个方位的断层图像检验中耳各个结构的连续性,并选择合适的方位建立新的二维断层图像。再将图片导入PHOTOSHOP软件行图片切割,再倒入逆向成型软件行三维重建,对各个部分在一个总体坐标系中分别重建,并对重建的几何结构行结构优化及分割。将重建的几何模型导入有限元软件进行组装及划分网格,简历有限元模型。最后赋予材料属性及边界条件进行运算,模拟结果同文献中的数据对比,检验有限元模型的有效性及合理性。结果：通过Micro-CT扫描产生的二维图片,质量较好,所有结构在整个图片集中可连续分辨。使用13微米及45微米重建图片均可用于三维重建。使用45微米重建三维几何模型,通过优化及分割后,曲率连续的面片形成。导入有限元软件,建立单元质量较好及数量尚可的网格模型。赋予材料属性及边界条件,进行模拟运算,同文献结果吻合较好。因内耳结构较为复杂,对膜迷路的标本准备尚缺乏经验,Micro-CT 13微米重建图片,对基底膜及前庭膜等结构的分辨仍然较差。结论：本模型优化程度较高,运算结果同文献结果拟合较好。本研究报道的建立包括外耳及中耳的有限元模型的方法可行,所建立的模型可用于模拟外耳及中耳病变。然而,人耳是一个整体,因条件及技术原因,内耳系统的重建方法需进一步探索。
[Abstract]:Objective: in this study, Micro-CT scanning of fresh human temporal bone samples was performed to obtain sectional images of the structures of the auricle, external auditory canal, middle ear and inner ear, excluding auricle, external auditory canal, middle ear and inner ear.The geometric model, mesh model and finite element model are established and verified with accurate fault images.The correct finite element model can be used to simulate the structure of normal and diseased external ear, middle ear and inner ear, to simulate abnormal and feasible repair measures, and to provide theoretical basis for the improvement of clinical operation.Methods: a fresh head of human cadaver was obtained from the Department of Anatomy of Shanghai Medical College of Fudan University. The external auditory canal and tympanic membrane were confirmed by endoscopy. The head of cadaver was dissected and the temporal bone of both sides was free.The specimens of the temporal bone should include the inner ear, the middle ear cavity, the mastoid chamber and the external auditory canal under the operation microscope, and can be fixed vertically in the scanning chamber.During Micro-CT scanning, the external auditory meatus was turned down and set to high precision scanning.After scanning, 13 渭 m and 45 渭 m were reconstructed, and both sets of data were saved in DICOM format.The data were imported into MIMIC software to select the window position and window width for the best display effect. The continuity of each structure of the middle ear was examined from the three azimuth tomograms, and a new two-dimensional tomography image was established by selecting the appropriate orientation.Then the images are imported into the PHOTOSHOP software line to cut the pictures, and then the reverse molding software is poured into the 3D reconstruction software. Each part is reconstructed in a general coordinate system, and the geometric structure of the reconstructed line is optimized and segmented.The reconstructed geometric model is imported into the finite element software to assemble and mesh, and resume the finite element model.Finally, the material properties and boundary conditions are given to operate, and the simulation results are compared with the data in the literature to verify the validity and rationality of the finite element model.Results: the quality of two-dimensional images generated by Micro-CT scan was good, and all structures could be continuously resolved in the whole picture set.Both 13 and 45 micron images can be used for 3D reconstruction.The 3D geometric model is reconstructed by 45 micron. After optimized and segmented, the surface with continuous curvature is formed.The finite element software is introduced and the mesh model with good quality and quantity is established.The material properties and boundary conditions are given, and the simulation results are in good agreement with the literature results.Due to the complex structure of the inner ear, the preparation of the membrane labyrinth specimen is still lack of experience in micro-CT 13 micron reconstruction images, and the resolution of the basement membrane and vestibular membrane is still poor.Conclusion: this model has a high degree of optimization, and the results fit well with the results of literature.In this study, the finite element model of the outer ear and middle ear is feasible, and the established model can be used to simulate the lesion of the outer ear and the middle ear.However, the human ear is a whole, because of the condition and the technical reason, the reconstruction method of the inner ear system needs to be further explored.
【学位授予单位】：复旦大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：R764

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