眼外肌的三维重建、测量及其应用

Extra-ocular muscle is important intra-orbital soft tissue and also the tissue frequently attained by many orbital diseases. The investigation on imaging change of extra-ocular muscle is crucial for diagnosis, evaluation and treatment for orbital diseases. In previous studies, manual outlining combined with computer-assisting reconstruction is the technique mostly used to define the intra-orbital structure. But it has the disadvantages including low efficiency, low objectivity, low accuracy and low replicability. Moreover, different intra-orbital soft tissues are similar in density and close in structure, so no appropriate method was yet built to separate the tissues and reconstruct them respectively. This study is a further investigation of our research series on orbital morphology. In this study, anatomically meaningful three - dimensional coordinates will be built. Extra-ocular muscle will be reconstructed into three-dimensional models and their changes in imaging properties will be investigated. The results of our study can provide quantitative evidence for orbital disease evaluation, help pre-operational planning and have many other applications in diagnosis and treatment.

眼外肌是眼眶内重要软组织。在各类眼眶病中，眼外肌也是较常受累组织。研究眼外肌的影像学改变是诊断、评估、治疗眼眶病的关键。既往眼外肌形态的研究主要采用手工描记后计算机合成的方法，存在效率低、客观性差、精确度低、可重复性差的缺点。并且，由于眶内各软组织密度相近且结构紧密互相包绕，一直没有合适的方法将眼外肌影像提取并重建。因此，此研究将在前期系列眼眶病形态学研究的基础上，拓展技术，制定具有解剖意义的眶面部三维坐标系，根据影像学特性，提取眼外肌影像并三维重建，研究其在生理状态及病理状态下的形态性质变化和位置移动。预期研究成果将能广泛应用于眼眶病诊治的各个方面，为眼眶病的观察评估提供定量依据，为手术治疗的术前设计提供数据支持。

研究背景目的. 根据眼眶病精确化研究的需要制定如下研究目的：构建标准化的三维坐标系，对眶面部结构进行定位和测量。构建骨性眼眶和眼外肌等眶内组织的有限元模型，进行动力学实验。.研究内容.1)编写计算机程序，在薄层CT图像系列上构建标准化眼眶三维坐标系。.2)在三维坐标系内定位和测量正常眼外肌等眶内结构。.3)构建骨性眼眶和眼外肌等眶内组织的有限元模型。.4)为有限元模型进行冲击动力学实验。.结果.1)标准化眼眶三维坐标系的构建方法具有很好的可重复性。.2)得出眶内结构位置和形态的正常值范围。正常眶内结构双侧对称；存在性别差异；一些形态变量间存在相关性。..3)得出骨性眼眶和眼外肌等眶内组织有限元模型的体积和详细CT值。.4)低速的钝性外力易造成眼眶爆裂性骨折；高速的钝性外力易造成眼球破裂伤。眶壁薄弱区能保护眼球在受到一定钝性外力冲击时避免破裂，而刚性材料修复的眼眶壁则不具有此保护作用。.科学意义.1)标准化眼眶三维坐标系可用于定位和测量眶面部结构。.2)骨性眼眶和眼外肌等眶内组织的有限元模型，可用于研究组织的立体形态和材料性质。.3)冲击动力学实验能模拟眼眶爆裂性骨折和眼球破裂伤的发生机制，分析所需外力条件和影响因素。