【作者】 陈蓉；

【导师】 张绍祥；

【作者基本信息】 第三军医大学 ， 人体解剖与组织胚胎学， 2009， 博士

【摘要】 目的1.分析临床颅脑减速伤的损伤特点,探讨其在临床伤情判断和影像诊断中的应用价值,并筛选有明确损伤力学边界条件的典型颅脑减速伤病例。2.利用动物实验进一步研究颅脑减速伤的损伤特点,探讨颅脑减速伤伤情、影像检查和病理特征之间的对应关系,补充、完善临床颅脑减速伤的损伤特点。3.构建基于中国可视化人体(Chinese visible human,CVH)的颅脑三维有限元模型,探讨高精度有限元模型的构建方法。4.进行基于事故再现的枕部颅脑减速伤的有限元模拟分析,探讨枕部颅脑减速伤的生物力学致伤机制,为颅脑减速伤的准确诊断和救治提供生物力学依据。方法1.分析近五年来临床上常见的颅脑减速伤病例的头部螺旋CT平扫资料,结合致伤病史及临床资料,分析颅脑减速伤的损伤特点。2.开展兔坠落式颅脑减速伤实验,应用常规CT平扫及CT灌注成像(Perfusion CT,PCT)检测颅脑减速伤的伤情,并与大体解剖、显微病理组织学观察进行对照,分析颅脑减速伤的CT表现与病理变化之间的关系。3.选取CVH数据集中颅脑连续薄层横断面图像作为数据源,应用PhotoShop CS3软件进行半自动图像分割,建立颅脑二维图像的分割数据。将分割后的数据导入Amira 4.1软件,采用面绘制算法进行三维重建,建立颅脑三维几何模型。然后在HyperMesh8.0软件中对颅脑三维面片模型进行实体建模、划分有限元网格和有限元模型装配,构建颅脑三维有限元模型。4.利用基于CVH的颅脑三维有限元模型,对筛选出的颅脑减速伤病例在LS-DYNA软件中进行事故再现,通过有限元模拟分析枕部减速冲击时颅脑的应力分布规律和特点,并与临床CT表现进行比较,分析枕部颅脑减速伤的生物力学致伤机制。结果与结论1.系统地分析了临床常见的颅脑减速伤伤情、CT影像特征,总结了颅脑减速伤损伤的主要特点。根据颅脑减速伤的损伤特点与致伤病史,可为临床颅脑损伤伤情的快速、准确判断与救治提供依据,为颅脑减速伤的CT影像扫描及诊断提供指导;根据颅脑减速伤的损伤特点与CT影像特征,可推测暴力作用部位和撞击力的作用过程,为颅脑创伤事故原因的评判提供理论依据。2.利用兔坠落实验成功再现了特定颅脑减速伤的致伤过程,得出兔颅脑减速伤的损伤特点主要表现为:头皮损伤和颅盖骨折位于撞击部位;颅底骨折比颅盖骨折多见且更严重,多位于前颅窝、中颅窝;硬膜下血肿多位于对冲部位;蛛网膜下腔出血是颅内最常见的病灶,多位于脑干周围和脑底部;脑挫裂伤位于撞击部位及对冲部位,以对冲部位损伤更严重。其病理和影像特征对临床颅脑减速伤的损伤特点作了有益补充。3.颅脑减速伤的CT表现与病理变化的良好对应关系,可为颅脑减速伤CT诊断提供明确的病理学依据;联合应用常规CT平扫及PCT扫描,可较满意地显示兔颅脑减速伤的损伤特点;PCT所显示的脑挫裂伤与病理解剖学观察的脑组织破损、出血、充血和水肿等范围接近,为临床PCT早期而敏感地检测脑挫裂伤提供了实验依据。4.建立了复杂解剖结构有限元模型构建的技术方法,成功构建了基于CVH的首例颅脑有限元模型,包括大脑、小脑、脑干、大脑镰、颅骨、上颌骨和下颌骨等结构,模型在完整性、精确性和代表性方面较现有的有限元模型更具优势,可作为颅脑结构生物力学分析的仿真实验平台。5.利用建立的颅脑有限元模型模拟分析枕部减速冲击时颅脑的应力分布规律,结果显示:枕部线性减速冲击时,除冲击部位下方颅骨及脑组织出现应力集中外,对冲部位也出现明显的应力集中区域,该应力分布特点不但与患者临床CT影像有良好的对应关系,而且与临床、动物实验颅脑减速伤的损伤特点相吻合。6.颅脑损伤分布与应力集中作用的关系,为颅脑减速伤的准确诊断和救治提供生物力学依据;基于CVH有限元模型的枕部颅脑减速伤的事故再现,为颅脑结构的应力传递和颅脑结构损伤的生物力学分析提供了技术平台;结合数字模型的应力分布特点可推测颅脑受力情况,为事故现场的还原提供辅助依据。更多还原

【Abstract】 Objective1. To study the value of injury judgment and imaging diagnosis of head deceleration injury (HDI) by analyzing the injury characteristics of HDI. In addition, a typical case of HDI would be used to reconstruction.2. Using an experimental model to further study the injury characteristics of HDI.To provide the beneficial supplementary for clinical HDI characteristics and definite pathological evidence for CT diagnosis of HDI.3. To build a 3D Chinese human head FE model based on the Chinese visible human (CVH) data set, and to study the reconstruction technique of high-quality FE model.4. To investigate the biomechanical mechanism of the occipital head impacted by accident reconstruction with FE method and provide biomechanical evidence for diagnosis and therapy of HDI.Methods1. By analyzing the conventional spiral CT imaging of head with HDI in our depatment,combined with the history of head impact and clinical data , the injury characteristics of HDI were summarized.2. Used an HDI experimental model of rabbit arising from falls, and the injury of HDI being detected with noncontrast CT and perfusion CT (PCT) approach. The detected results were compared with macroanatomy and microscopy to investigate the relations between CT findings and pathological injury.3. Successive thin-layer cross-sectional images of head were retrieved from the second CVH data set, and semi-automated segment with Photoshop CS3 software to acquire segmented data of two-dimensional (2D) head images. By using Amira 4.1 software, the segmented data were reconstructed to get head three-dimensional (3D) geometrical model of surface rendering. In Hypermesh 8.0 software, entity model reconstruction, meshing of FE and assembling of FE models have been done and a head FE model based on Chinese human was developed.4. Accident reconstruction for the HDI case was performed using LS-DYNA software, and the distribution characteristics of stress could be acquired by the numerical analysis with the FE model based on the CVH. The simulation results were compared with CT findings of case, and the biomechanical mechanism of HDI was discussed.Results and conclusions1. The traumatic condition and CT findings of HDI clinical patients, and summarized the injury characteristics of HDI were systematically analyzed. According to HDI characteristics and the history of head impact, it can help to provide the evidence for clinical rapidly, accurate judgment and therapy of head injury, and help to guide CT scanning and diagnosis of brain injury. According to HDI characteristics and CT findings, the site of impact and of the course of the traumatizing force can be deduced, and the data obtained by this procedure may theoretically provide the evidence for judgment the cause of head trauma accident.2. The course of the definite HDI traumatizing was reconstructed by using an experimental model of rabbit arising from falls, and the HDI characteristics in rabbit were as follows: scalp contusion and cranial fracture at coup site; basal fracture was more severe than cranial fracture, with more cases at the anterior or middle fossa; subdural hematoma mainly at contrecoup site; subarachnoid hemorrhage was the most frequent lesions of intracalvarium, mainly around brainstem and the ventral aspect of the brain; cerebral contusion at both coup and contrecoup site, the lesions at the site of contrecoup were more severe. The feature of pathology and CT imaging provided the beneficial supplementary for clinical HDI characteristics.3. The good corresponding relationship between pathology and CT imaging of HDI can provided the definite pathological evidence for CT diagnosis. The HDI characteristics can be satisfactorily assessed by means of combining NcCT and PCT scans. Contused areas in PCT matched pathoanatomical brain tissue breakage, bleeding, hyperemia and edema regions, which provided the experimental evidence for early and sensitive detection of cerebral contusions.4. A reconstruction methodology of FE model with complicated anatomic structure has been developed. The fist FE model based on the CVH was successfully constructed, including cerebrum, cerebellum, brainstem, cerebral falx, skull, maxillae and submaxilla. The FE model was superior to other FE model in integrality, truth and representation. The model was very helpful in the field of head biomechanical analysis simulation platform.5. The distribution characteristics of head stress were simulated by the FE analysis HDI of the occipital head impacted. As results, the Von-Mises stress was centralized in the area of skull and brain not only at the impact site but also the contrecoup site. The distribution characteristic of higher Von-Mises stress levels showed a good agreement with that of the injured region on the CT imaging, and was accorded with the injury characteristics of DHI of clinical patients and animal experiment.6. The relationship between head injury distribution and stress centralization may provide theoretical evidence for diagnosis and therapy of HDI. Accident reconstruction based on the CVH FE model may provide the technique platform for the diffusion of head stress and biomechanical analysis of head injury. Combined with the stress distribution characteristic of digitized model, the traumatizing force can be deduced, which can provide the assistant proof for accident reconstruction.更多还原