【作者】 冯婷；

【导师】 赵书俊； 单保慈；

【作者基本信息】 郑州大学 ， 测试计量技术及仪器， 2019， 硕士

【摘要】 脑是人体最为复杂的器官之一,大脑内多个脑区协调运作,高效地整合信息和分工,构成了一个复杂的脑网络,其中,脑白质作为神经中枢系统的重要组成部分,主要负责脑网络内的信息传输。许多重大脑疾病在发病初期常表现为脑网络的紊乱,如自闭症、抑郁症等,因此,对脑网络的研究是目前神经科学研究的重点及热点。扩散张量成像技术(Diffusion Tensor Imaging,DTI)依据脑内水分子扩散的三维位移分布,能够在体且无创地对脑白质及脑结构网络进行成像,为脑白质的研究提供了强有力的手段,目前已被广泛应用于术前评估及重大脑疾病和脑结构网络的基础研究中。然而与传统的磁共振成像不同,研究人员无法通过读片的方式直接观察脑白质及脑结构网络,因此,数据分析是DTI成像技术应用于脑疾病研究的关键,目前常用的方法有定量计算、纤维追踪、网络构建等。动物实验在神经科学的研究中占有举足轻重的作用,其中,猕猴以其具有与人类高度相似的行为学特性及生物学特性,被越来越多地应用于重大脑疾病的基础研究中。相比于传统的组织切片等实验手段,对模型猕猴进行在体的DTI成像,不仅能够大大的降低实验成本,还能够通过横向对比及纵向的跟踪的方法,全面地研究重大脑疾病在发生、发展过程中脑白质及脑结构网络的变化。随着国内外猕猴DTI脑成像实验的广泛开展,如何对其进行有效的数据分析成为目前亟待解决的问题。为了能够对猕猴DTI脑成像进行客观的数据分析,首先需要建立具有群体代表性的猕猴脑白质图谱及扩散张量脑模板。猕猴脑图谱有助于探索脑功能特性并了解脑结构,是连接生物医学和医学影像学的桥梁,对脑结构网络的分析至关重要。基于全脑白质纤维的猕猴脑白质网络可以定量分析纤维连接、脑网络拓扑属性。目前,猕猴脑图谱的研究并不全面,无法精确地描绘活体状态下三维白质纤维束的形态结构、走行方向及连接情况。猕猴脑白质网络的研究甚少,无法在脑图谱的基础上理解脑白质的分布及信息传输。因此,本论文着重于猕猴扩散张量脑模板、脑白质图谱、脑白质网络的构建与分析。本文在国内外发展现状的基础上,以30只健康恒河猴为研究对象,开展了以下研究工作:第一,提出利用基于q空间的DWI标准化方法将DTI图像配准至标准空间,建立了基于扩散张量的猕猴FA、MD、b0像标准脑模板。第二,采用确定性纤维束追踪算法获得了标准空间下的全脑白质纤维束,依据虚拟分割手工地勾画了主要的白质纤维束,并平均30只猕猴的纤维束图构建了猕猴脑白质图谱。脑白质图谱能够很好地描绘各种尺寸微小、形态结构不同的三维白质纤维,可提取某种特定纤维束进行定量分析,辅助脑外科手术。第三,在前两部分工作的基础上利用已建立的猕猴标准脑图集构建了基于纤维束追踪的猕猴脑白质网络,分析了网络的全局及局部效率、小世界属性,且对猕猴脑白质网络进行了模块划分,进一步分析了网络的hub节点。基于纤维追踪的猕猴脑白质网络有益于研究脑网络的模块化、核心脑区及复杂脑功能的实现。更多还原

【Abstract】 The brain is one of the most complex organs in the human body.Multiple brain regions in the brain operate in coordination and efficiently integrate information and division of labor,forming a complex brain network.Among them,as an important part of the central nervous system,white matter is mainly responsible for the information transmission in the brain network.Many major brain diseases are often manifested as the disorder of brain network in the early stage,such as autism,depression,etc.Therefore,the research on brain network is the focus and hotspot of current neuroscience research.Diffusion tensor imaging is able to show brain white matter and brain structure network in vivo and non-invasively,based on the three-dimensional displacement distribution of water molecules in the brain.DTI technique provides a powerful method to the research of cerebral white matter and it has been widely applied in the basic research of preoperative assessment,major brain disease and brain structural network.However,it is different from the traditional magnetic resonance imaging,researchers cannot directly observe the white matter and brain structure network by reading medical images.Therefore,data analysis is the key to the application of DTI imaging technology in the study of brain diseases.Currently,the commonly used methods include quantitative calculation,fiber tracking,network construction and so on.Animal experiments play an important role in the research of neuroscience.Among them,rhesus monkeys,with highly similar behavioral and biological characteristics to humans,are increasingly used in the basic research of major brain diseases.Compared with traditional experimental methods such as tissue sections,DTI imaging of model macaques in vivo can not only greatly reduce the experimental cost,but also comprehensively study the changes of white matter and brain structure network during the occurrence and development of major brain diseases by means of horizontal comparison and longitudinal tracking.With the extensive development of rhesus monkey DTI brain imaging experiments at home and abroad,how toeffectively analyze its data has become an urgent problem to be solved.In order to conduct objective data analysis on rhesus monkey DTI brain imaging,the rhesus monkey brain white matter atlas and diffusion tensor brain templates with a representative population need to be established first.Rhesus monkey brain atlas is helpful to explore the functional characteristics of the brain and to understand the brain structure.It is a bridge between biomedicine and medical imaging,and is of great importance to the analysis of the brain anatomical network.The network based on whole white matter fiber can quantitatively analyze the topology properties of brain network and fiber connection.At present,the study of rhesus monkey brain atlas is not comprehensive and the morphological structure,direction and connection of three-dimensional white matter fibers can not be described accurately and in vivo.There are few studies on the white matter network in rhesus monkeys.Therefore,this paper focused on the construction and analysis of diffusion tensor brain templates,white matter atlas and white matter network was proposed.In this paper,on the basis of overseas and domestic research status,this paper took thirty healthy rhesus monkeys as the research objects and carried out the following research work:First,DWI standardization method based on the q space was proposed to to register DTI images into the standard space.The macaque FA,MD,b0 brain templates based on diffusion tensor were established.Second,the whole white matter fibers in the standard space were obtained by using the deterministic fiber tracking algorithm,the main white matter fibers were manually drawn by virtual segmentation,and the white matter fiber maps of thirty rhesus monkeys were averaged to constructe the macaque brain white matter atlas.The white matter atlas based DTI can describe the three-dimensional white matter fibers well,and it is applied to extract a specific kind of fibers for quantitative analysis.It is widely used to assist brain surgery in the field of neuroscience.Thirdly,on the basis of the previous two parts,the established standard brain atlas of the rhesus monkey was used to construct the rhesus macaques cerebral white matter network based on fiber tracking,the global and local efficiency,small-world properties of the network were analyzed.Moreover,the module division of the macaque cerebral white matter network was conducted,and the hub nodes of the network were further analyzed.Brain white matter network of the rhesus monkey based on fiber tracking is beneficial to the study for modularization of brain network and core brain regions,realization of complex brain function.更多还原