失语症多模态影像特征研究

发布时间：2018-05-17 09:51

本文选题：脑卒中失语症 + 功能磁共振成像　；参考：《电子科技大学》2016年博士论文

【摘要】：失语症是指获得性语言障碍,因大脑皮层(优势半球)的语言中枢损伤所引起的语言理解和表达能力受损。其中由优势半球脑卒中所引起的失语症,也称脑卒中后失语症,最为常见。众多结构、功能神经影像技术已经广泛用以探究其失语患者的语言损害、恢复及其神经生理机制。但脑卒中后失语症患者脑部功能和结构变化仍不明确,需要融合多模态脑影像方法进行深入的探究。本文融合多模态的静息态功能磁共振成像、三维T1结构成像和弥散张量成像,探测失语患者脑功能和结构异常变化的影像特征,为临床诊断和评估提供客观的神经影像学依据。主要内容如下:(1)针对脑卒中失语症患者静息态脑功能活动局部一致性改变的问题,通过计算17名脑卒中后失语症患者和20名年龄、性别和受教育程度相匹配的健康对照的局部一致性来研究大脑局部区域同步性变化,检测了异常局部一致性值和脑卒中失语症患者的失语症严重程度的相关性。结果发现:与正常对照组相比,脑卒中失语症患者的右侧舌回、左侧距状沟、楔叶、额上回以及额上回内侧的局部区域同步性降低。且左侧额上回内侧的局部同步性与汉语失语成套测验(ABC)中的失语症严重程度(r=0.55,P=0.027)及命名分数(r=0.66,P=0.005)呈正相关。这一结果表明脑卒中失语症的发病机理可能归因于多个局部脑区同步化的异常。(2)针对脑卒中后失语症脑功能局部活动强度的异常和该区域引起的脑功能连接改变的问题,采用静息态功能磁共振成像结合低频振幅和区域间功能连接分析方法,探测失语症患者的局部脑活动和远程脑网络功能连接的改变。采用17名左半球脑卒中的失语患者与20名年龄、性别和受教育程度相匹配的正常对照作为研究对象。失语症患者主要在右侧颞叶内侧(海马/海马旁回)和左侧颞皮层部位表现出局部区域内脑活动显著增强。而右侧海马/海马旁回的局部区域内脑活动强度和造句能力呈负相关。失语症患者的远程脑网络功能连接在右侧海马/海马旁回和梭状回间增强,但在左侧枕叶和顶叶皮质降低。这些结果显示出失语症患者局部区域内大脑功能障碍和区域间的功能连接相关。局部区域内脑功能活动强度和远程脑网络连接可为失语症的病理生理学机制的深入理解提供客观的影像学特征。(3)针对脑卒中后失语症患者脑局部结构异常以及该区域脑功能连接的变化,采用结合基于体素形态学灰质体积度量和静息态功能连接的方法探测脑卒中失语症患者的脑结构和功能网络的改变。本研究采用基于体素形态学测量法检测17名脑卒中失语症患者与年龄、性别、受教育程度相匹配的20名正常对照灰质体积相异的特定脑区,进而检测灰质的异常与功能连接改变之间是否存在关联。最后,计算异常功能连接与失语症患者的临床量表分数之间的相关性。结果显示失语症患者的右侧颞上回、顶下小叶/缘上回以及左侧枕中回的灰质体积显著升高,而右侧尾状回和双侧丘脑的灰质体积显著降低。患者的右侧顶下小叶/缘上回与右侧楔前叶、角回、枕上回之间的远程功能连接增强,而右侧尾状回与辅助运动区、背外侧额上回之间的功能连接减弱。同时发现左侧枕中回与左侧眶部额中回的功能连接强度与操作指数呈正相关。我们推测失语症患者的灰质体积异常可能会导致脑区间的功能连接改变。这些结果将为理解脑卒中失语症的发病机制提供结构和功能影像方面的证据。(4)针对脑卒中后失语症全脑功能连接模式中关键网络特征的个体识别问题,采用基于全脑功能连接为特征的多变量模式分析方法来识别失语症患者和正常对照。本实验对17名失语症患者与20名年龄、性别和受教育程度相匹配的健康对照的功能影像数据进行模式识别分析,首先通过功能连接方法得到两组人的功能网络,选择其主要特征,采用支持向量机进行模式分类。结果显示:失语症患者分类正确率最高可达86.5%,灵敏度可达76.5%,特异性可达95.0%。此外,核心连接主要是位于额顶叶网络、听觉网络、感觉运动网络和视觉网络,而右侧罗兰迪克岛盖对分类贡献最大。实验结果表明全脑功能连接可以作为一个潜在的神经学标识,用以区分失语症患者和健康人。(5)针对失语症患者脑腹侧与背侧语言通路纤维连接受损的问题,采用全脑无偏空间统计方法分析脑卒中失语症患者和正常对照白质纤维连接的改变。本实验选用了18名脑卒中失语症患者和20名年龄、性别、受教育程度相匹配的正常对照,进行语言评估和弥散张量成像扫描。采用全脑无偏空间统计方法来估计每组被试的白质完整性(即部分各向异性),用线性相关分析法评估白质的完整性和临床量表值的关系。结果显示失语症患者左下额枕纤维素\下纵束、左侧钩状纤维束和左侧上纵束的白质纤维完整性减少。此外,左下额枕纤维束和左上纵束的白质纤维完整性分别与失语指数(AQ)、操作指数(PQ)和皮层指数(CQ)成正相关。左下额枕纤维素\下纵束与左上纵束分别是腹侧和背侧语言通路的重要组成部分,因此,本研究表明白质纤维完整性的损伤,即多个背侧和腹侧结构连接的缺失,而导致语言表达缺失和认知功能损害。因此,上述多重结构连接的缺失可作为脑卒中失语症的重要生物学标记。
[Abstract]:Aphasia refers to the impairment of language comprehension and expression caused by the impairment of the language center of the cerebral cortex (the dominant hemisphere). The aphasia caused by the stroke in the dominant hemisphere, also known as post stroke aphasia, is the most common. Many structures are widely used to explore their aphasia. The changes in the brain function and structure of the patients with aphasia after stroke are still not clear, and the multimodal brain imaging methods need to be integrated in depth. This paper combines multimodal resting state functional magnetic resonance imaging, three-dimensional T1 structure imaging and diffusion tensor imaging, to detect the brain work of aphasia patients. The image features of abnormal changes of energy and structure provide an objective neuroimaging basis for clinical diagnosis and evaluation. The main contents are as follows: (1) according to the problem of local conformance changes in resting state brain function of stroke patients with aphasia, 17 patients with aphasia after stroke and 20 age, sex, and educational level are calculated. The local consistency of the matched healthy controls was used to study local regional synchrony changes in the brain, and the correlation between abnormal local consistency and the severity of aphasia in patients with aphasia was detected. Results: the right tongue gyrus, left spur trench, wedge, upper frontal gyrus and forehead of stroke patients with aphasia were compared with the normal control group. The local synchronization in the medial part of the gyrus was reduced, and the local synchrony of the medial upper frontal gyrus was positively correlated with the r=0.55 (P=0.027) and the naming score (r=0.66, P=0.005) in the Chinese aphasia test (ABC). The results suggest that the pathogenesis of stroke aphasia may be attributed to the synchronization of multiple local brain regions. (2) in view of the abnormality of local activity intensity of cerebral apoplexy after stroke and the change of brain function connection caused by this region, resting state function magnetic resonance imaging (fMRI) combined with low frequency amplitude and interregional functional connection analysis to detect the changes of local brain activity and remote brain network function connection in aphasia patients. 17 apoplexy patients with left hemisphere apoplexy were studied with 20 normal controls matched with age, sex and education. Patients with aphasia showed significant regional brain activity in the medial temporal (hippocampus / parahippocampal gyrus) and left temporal cortex, while the right hippocampal / parahippocampal gyrus was in the local area. The intensity of internal brain activity was negatively correlated with the ability to create a sentence. The tele network functional connections of the patients with aphasia were enhanced in the right hippocampus / parahippocampal gyrus and spindle gyrus, but decreased in the left occipital and parietal cortex. These results showed that the brain dysfunction and regional functional connections in the local area of aphasia patients were related. The intensity of brain function and the distance of remote brain network can provide objective imaging features for the in-depth understanding of the pathophysiological mechanism of aphasia. (3) according to the changes in the local structure of the brain and the changes in the brain function connection in the aphasic patients after stroke, a combination of voxel based morphologic gray volume measurement and resting state function connection is used. This study was used to detect the changes in the brain structure and functional network of patients with apoplexy aphasia. In this study, a voxel based morphometry was used to detect the specific brain areas of 17 patients with apoplexy aphasia and 20 normal controls of age, sex and education, and then the abnormal and functional connection of gray matter was detected. Finally, the correlation between the abnormal functional connection and the clinical scale of the aphasic patients was calculated. The results showed that the right temporal upper temporal gyrus, the subapietal lobule / superior gyrus and the left occipital gyrus increased significantly, while the right caudate gyrus and the volume of gray matter in the bilateral thalamus decreased significantly. The functional connection between the right side of the right parietal lobule / upper margin and the right anterior wedge, the angular gyrus and the upper occipital gyrus was enhanced, while the functional connection between the right caudate gyrus and the accessory dorsal frontal gyrus was weakened. We also found that the functional connection between the left occipital gyrus and the left orbital frontal gyrus was positively correlated with the operation index. We speculated that the functional connection was positively related to the operation index. The abnormal volume of gray matter in aphasic patients may lead to functional connectivity changes in the brain region. These results will provide structural and functional evidence for understanding the pathogenesis of apoplexy aphasia. (4) the individual identification of key network characteristics in the whole brain function connection model after stroke, is based on the whole brain. The functional connectivity was characterized by a multivariable model analysis method to identify aphasia patients and normal controls. This experiment was conducted to analyze the functional image data of 17 patients with aphasia and 20 healthy controls matched with age, sex and education. First, functional networks were obtained by functional connection to select the functional networks of two groups of people. The results show that the classification accuracy of the aphasia is up to 86.5%, the sensitivity is up to 76.5%, the specificity can reach 95.0%., and the core connection is mainly located in the frontal parietal network, the auditory network, the sensorimotor network and the visual network, while the right Roland Dick Island cover contributes to the classification. The experimental results show that the whole brain functional connection can be used as a potential neurologic marker to distinguish between aphasia patients and healthy persons. (5) to analyze the problem of impaired fibrous connection between the ventral and dorsal language pathways of aphasic patients, the whole brain unbiased space statistics method is used to analyze the apoplexy aphasia patients and normal control white matter fiber. In this experiment, 18 patients with apoplexy aphasia and 20 normal controls with age, sex, and educational level were used to perform language assessment and diffusion tensor imaging. The whole brain unbiased space statistical method was used to estimate the white matter integrity (i.e., partial anisotropy) in each group, and the linear correlation analysis was used. The results showed that the integrity of the left inferior occipital fiber, the left hook fiber bundle and the left superior longitudinal bundle decreased the integrity of white matter fibers in the left inferior occipital fiber, and the white fiber integrity and the aphasia index (AQ), the operation index (PQ) and the cortex in the left inferior occipital bundle and the left superior longitudinal bundle. The index (CQ) has a positive correlation. The lower longitudinal and upper left longitudinal bundles of the left inferior occipital fiber are an important part of the ventral and dorsal language pathway. Therefore, this study shows that the integrity of the white matter fiber is damaged, that is, the loss of multiple dorsal and ventral structures, which leads to the loss of language and the impairment of cognitive function. Absence of connections can be used as an important biological marker for aphasia in stroke.
【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R445.2;R743.3

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