【作者】 王岩；

【导师】 蔡爱露；

【作者基本信息】 中国医科大学 ， 影像医学与核医学， 2010， 博士

【摘要】 前言椎基底动脉系统又称为后循环。主要供应脑干和小脑后血供,后循环缺血是常见的缺血性脑血管病,约占缺血性卒中的20%。临床表现为后循环缺血引起的肢体乏力、眩晕、共济失调、头疼、晕厥等症状。其病因多见于椎动脉狭窄或闭塞导致的血流动力学性的低灌注。神经系统对缺血很敏感,神经细胞缺血后死亡的主要方式不是坏死,而是凋亡。由于脑干是重要的神经活动部位,脑神经、网状上行激活系统和重要的上下行传导束在其间通过,当血供障碍时,可造成延髓、桥脑和部分颅神经的功能障碍,会出现各种不同但又相互重叠的临床表现。凋亡或抗凋亡均是多样性、偶联性、多途径的信号转导过程。脑缺血后神经元发生细胞凋亡的最有力的证据是关于其分子机制的研究,近些年由于对细胞凋亡机制的发现与研究,越来越多的实验证明神经系统的疾病,如癫痫、帕金森氏病、老年痴呆症、脑缺血等,与细胞凋亡之间存在着密切关系。本研究首先得到小儿椎动脉正常和异常血流参数；然后建立兔后循环缺血模型,模拟临床改变进行实验研究,采用彩色多普勒超声技术得到实验兔椎动脉血流量,血流速度等血流动力学参数,进行对比研究,评价有无后循环供血不足；通过对试验兔脑组织进行染色,观察后循环供血区域神经细胞形态学改变,计算脑干神经细胞凋亡指数等,进行超声检测的血流参数与凋亡指数之间的相关性分析,为该病的准确诊断提供确切的理论和实验依据。材料与方法1、2007年12月-2008年12月,在我院神经内科就诊的156例患儿,主述头痛,头晕,晕厥等头部症状,使用美国产GE LOGIC 7彩色多普勒超声诊断仪,探头频率为10MHz,行超声检查,检测出先天性椎动脉异常病例42例,12例为椎动脉发育不对称,15例为椎动脉椎间孔处扭曲,5例为双侧椎动脉发育不对称伴发椎动脉扭曲,6例为先天性椎动脉发育不良,4例患儿椎动脉起源和走行异常。另选86例2-14岁正常儿童作为对照组,对照组血管内径和血流动力学参数经统计学处理无显著差异(p>0.05)。所有病例组患儿都进行了脑电图检查,结果为阴性。超声检查患儿的椎动脉声像图资料,包括椎动脉内径、走行、搏动、频谱形态、血流量等。2、2009年1月-2010年2月,选择61只日本大耳白兔作为研究对象。使用日本产阿洛卡α10彩色多普勒超声诊断仪,探头频率为10MHz。兔麻醉后记录双侧椎动脉二维超声及彩色多普勒超声声像图特点,建立兔椎动脉结扎和狭窄模型,为椎动脉结扎组、椎动脉狭窄组,比较各组参数之间差异,于术后2小时、1天、2天等不同时间对试验兔进行超声检查,得到二维和彩色多普勒血流动力学参数,探讨临床改变的病理基础。3、处死试验兔,取基底动脉全长的脑干组织,HE染色,观察缺血后细胞形态改变,并进行脑干调亡细胞的检测,计算调亡指数,对不同组别的凋亡指数进行统计分析；分析椎动脉病例组血流参数与脑干调亡指数的相关性。结果1、156个患儿中检测出先天性椎动脉异常病例42例,椎动脉发育不对称组12例,椎动脉椎间孔处扭曲组15例,双侧椎动脉发育不对称伴发椎动脉扭曲组5例,先天性椎动脉发育不良组6例,患儿椎动脉起源和走行异常组4例,组成5个病例组。小儿正常对照组与5个病例组之间比较显示6组之间双侧内径、PSV、血流量(volume)存在差异,p<0.05；5个病例组患侧和对照组间比较EDV、RI存在差异,p<0.05。椎动脉发育不对称组12例,为双侧椎动脉内径相差1mm以上,其中左侧4例,右侧8例,双侧椎动脉内径、volume与正常对照组比较p<0.05,健侧EDV与正常对照组比较差异显著,p<0.05,患侧PI、RI与正常对照组比较差异显著,p<0.05。椎动脉椎间孔处扭曲组15例,发生在双侧5例,左侧5例,右侧5例,健侧椎动脉PSV、EDV、volume与正常对照组比较,p<0.05。双侧椎动脉发育不对称伴发椎动脉扭曲组5例,扭曲均发生在右侧,不对称右侧3例,左侧2例,患侧内径细,与正常对照组比较p<0.05,健侧血流量增加,与正常对照组比较p<0.05。先天性椎动脉发育不良组6例,内径小于2mm,管壁增厚,血流充盈不良,搏动减弱,发生在左侧5例,右侧1例,患侧内径、PSV、EDV、volume与对照组相比减少、下降明显,p<0.05。患儿椎动脉起源和走行异常组4例,其中椎动脉起始段从主动脉弓直接起源1例,2例椎动脉越过第6、5椎间孔后进入第4椎间孔上行,1例越过第6椎间孔后入第5椎间孔上行,患侧与正常对照组比较内径、PSV有统计学意义,内径小于正常对照组,PSV高于正常对照组,p<0.05。健侧内径、EDV、PI、RI与对照组比较有统计学意义,健侧椎动脉内径增宽,EDV速度增快,阻力减小,以代偿性增加椎基底动脉血供。2、构建兔后循环缺血模型,1组为对照组,2组为椎动脉100%结扎组,3组为椎动脉70%-100%狭窄组。分别于术后2小时、1天、2天、3天、4天、5天、6天将实验兔麻醉进行椎动脉超声检查,获得血流动力学参数。正常对照组和两病例组之间比较显示三组之间PSV、EDV、volume、PI、RI有统计学意义,p<0.05。结扎组与正常对照组比较健侧血流速度加快,血流量增加,p<0.05,组内比较术后不同时间PSV、EDV呈上升趋势,p<0.05。狭窄组与正常对照组比较,健侧PSV、EDV、volume增高明显,PI、RI下降明显,有统计学意义,p<0.05,而患侧PSV、PI、RI、volume与正常对照组相比,下降明显,也有统计学意义,p<0.05,组内比较术后不同时间血流动力学参数无统计学意义,p>0.05。3、取实验兔基底动脉全长的脑干,10%中性缓冲福尔马林固定4小时以上,石蜡包埋,在每个基底动脉中段取材,每点取1个切片,层厚3μm。HE染色后镜下观察椎动脉不同狭窄程度其供血区域的结构变化,以神经元的形态学变化作为缺血的判定指标。镜下观察凋亡细胞,计算凋亡指数。4、正常对照组与病例组之间凋亡指数采用单因素方差分析显示无统计学意义,p>0.05。椎动脉结扎组组内凋亡指数统计分析显示,随动物模型取材时间不同,凋亡指数呈上升趋势,而狭窄组随不同取材时间与脑干凋亡指数之间无相关性,p>0.05,无统计学意义。实验兔病例组超声血流参数与脑干凋亡指数之间Pearson相关分析显示呈正相关,凋亡指数与模型存活时间、PSV、volume呈正相关,p<0.05。结论1、超声检查能够比较准确地显示小儿颅外段异常椎动脉的形态和走行。2、二维超声得到的形态学改变结合血流动力学参数对评价先天性小儿椎动脉异常及后循环血供上具有很高的临床应用价值。3、通过建立动物模型来研究后循环缺血,与临床椎基底动脉供血障碍非常接近,在理论上和医学临床实践上都有一定的意义。4、实验兔病例组凋亡指数与血流动力学参数相关性分析,一方面说明椎动脉狭窄和闭塞与脑干细胞的凋亡有关,证实缺血时间与细胞凋亡之间的密切相关性,另一方面说明随着生存时间逐渐延长,机体会通过提高血流速度、增加后循环血流量等进行代偿,以维持机体的正常生存状态。更多还原

【Abstract】 IntroductionVertebrobasilar system is also called posterior circulation, which mainly provide blood supply to brain stem and posterior cerebellum. Blood insufficiency in posterior circulation is a common cerebral vessel disease. It makes up about 20% in oblitting of short blood supply. Its clinic presentation are languid limb、dizziness、ataxia、headache and syncope caused by blood insufficiency in posterior circulation. The reason for it is usually the lower perfusion caused by narrowness and occlusion of vertebral artery. Nervous system is much sensitive to blood short supply. Nerve cell die for apoptosis, not by necrosis after blood short supply in brain.Brain stem is an important nervous active position. Cerebral nerve、reticular formation and up-and-down conductive bunches go through in it. Once blood insufficiency happened, there will be some different and overlap clinic presentations because of malfunction in medulla oblongata、pons and some cerebral nerves.Apoptosis and anti-apoptosis are all signal transduction procedure that are diversity、connective and multi-roads. The most powerful evidence to test apoptosis after blood short supply in brain is the study of its molecular mechanism.These years more and more researches have demonstrated that some nervous system disease such as epileptic、parkinsonism、senile dementia and blood insufficiency in brain have close relationship with apoptosis along with the development of apoptosis mechanism.This study is to get normal and abnormal ultrasonographic data from vertebral artery in children. Then building up the rabbit models which have blood insufficiency in posterior circulation. Imitating clinic changes to perform the experiment. Volume and other hemodynamic data are got in color Doppler flow imaging. In comparison with each other to evaluate blood supply in posterior circulation. The slice of brain stem are got to dye to identify the morphology of nerve cell in insufficiency area. Apoptosis index are calculated. The correlation is analyzed between data got from ultrasonography and apoptosis index. Which can provide the tangible theory and experiment gist to diagnose the disease.Materials and Methods1. From November 2007 to November 2008,156 children came to our hospital. The complaints are headache、dizziness and syncope. GE Logic 7 were used to perform the examination. The frequency of probe is 10MHz.42 cases were detected.12 patients had asymmetric underdevelopment of the vertebral artery.15 had tortuosity of the extracranial vertebral artery.5 had bilateral asymmetric underdevelopment of the vertebral artery with tortuosity on the right side.6 had a congenital hypoplastic vertebral artery. And 4 had an abnormality of the path of the vertebral artery.In addition, 86 unaffected children aged 2 to 14 years were included as a control group. By statistical analysis, the results showed no significant variations in the control group. All patients underwent electroencephalography, which yielded negative findings in all cases. The information we got from ultrasnography is diameter、course、pulsating、wave configuration、volume.2. From January 2009 to February 2010,50 rabbits are chosen to be study. Alokaα10 were used to perform the examination.The frequency of probe is 10MHz. Ultrasonographic characteristics about 2-dimensional and CDFI are got after rabbits anesthetized. Building up the animal models whose vertebral artery is narrowness and occlusion. Comparing data discrepancy with each groups. Performing and getting data from models in diffirent time to explain the pathologic basis of clinic changes.3. Executing rabbit models to get brain stem which include the whole basilar artery. The cell morphology are observed after dyed in HE. Apoptosis index are calculated and analysed in statistic ways among different group. Correlation between the hemodynamic data and apoptosis index is studied.Results1.42 cases among 156 children are diagnosed congenital anomaly in vertebral artery. The group of asymmetric underdevelopment of the vertebral artery has 12 patients. The tortuosity of the extracranial vertebral artery has 15cases. The bilateral asymmetric underdevelopment of the vertebral artery with tortuosity has 5 cases. The group of congenital hypoplastic vertebral artery has 6 cases. The abnormality of the path of the vertebral artery has 4 cases. They consist of 5 case groups. In the comparison between the normal control group and the 5 case groups, it showed that bilateral diameters、PSV and volumes of these six groups had variations (p < 0.05). EDV、RI in disease side is significance, p< 0.05.The group of asymmetric development of vertebral artery has 12 cases. The bilateral diameters of vertebral arteries could vary by more than lmm, in which 4 were on left side and 8 were on right side. The bilateral diameters and volumes of vertebral arteries were compared to the normal control group is significant (p< 0.05). EDV in healthy side is significant in comparison with the control group. While PI、RI in disease side comparing with control has variations (p<0.05).The group of tortuosity of vertebral artery at intervertebral foramen has 15 cases, in which 5 had it on both sides,5 had it on left side, and 5 had it on right side. The PSV、EDV、volume in healthy side, in comparison to the control group, was significantly increased (p< 0.05).The group of bilateral congenital asymmetry with tortuosity has 5 cases, tortuosity was reported all on right side, while 3 had asymmetry on right side and 2 had asymmetry on left side. The internal diameters in disease sides, when compared to normal control group, showed narrow and p< 0.05. The volume in healthy side showed higher and p<0.05.The group of congenital hypoplastic vertebral artery has 6 cases. Internal diameter was less than 2mm, with thickening wall and inadequate blood flow. It was shown as blurry darkness and weakened pulse in vascular wall.5 had it on left side and 1 had it on right side. The comparison of internal diameter、PSV、EDV of diseased side and its volume to the normal control group revealed p-value of less than 0.05.The group of merely abnormal original and path of vertebral arteryhas 4 patients. One had direct origin from aortic arch for the start point of vertebral artery. Two had the crossing of vertebral artery from the fifth and the sixth intervertebral foramens before entering the fourth foramen for upward traveling. One had the crossing of vertebral artery from the sixth intervertebral foramen before entering the fifth one for upward traveling. In comparison with control, internal diameter、PSV in disease side has variation (p<0.05).While internal diameter、EDV、PI、RI in healthy side has variations comparing with the control to compensate blood supply.2. Building up rabbits models which have insufficiency blood supply in posterior circulation. One group is the control. The second group is 100% occlusion at one side of vertebral artery. The third group is 70%-100% narrowness at one side of vertebral artery. Performing ultrasonography and getting data from it at different time to get hemodynamic data.In the comparison between the normal control group and the 2 case groups, it showed that PSV、EDV、volume、PI、RI is significance (p＜0.05)The second group showed high speed PSV and much volume in healthy side than control (p<0.05). PSV、EDV have the increasing tendency after operation day by day.The third group, PSV、EDV、PI、RI in healthy side, has variations in comparing with control. While PI、RI、volume in occlusion side decreased and showed significance too (p<0.05).3. Getting brain stem of rabbits covering the whole basilar artery and fixation over 4 hours in 10% neutral formalin. In the middle of brain stem taking out the material. The slice is 3μm.Dying by HE and observing the structure changes of insufficiency area. The determinant guideline of blood insufficiency area is the changes of morphology of nerve cell. Apoptosis cell is observed under microscope and apoptosis index is calculated.4. Comparing apoptosis index between control and case groups is no significance in the method of One-way ANOVA (p>0.05). Apoptosis index showed increased tendency within second group which is significance at different time of taking out material, p<0.05. While within third group, it is no significance, p>0.05.The hemodynamic data from case groups is positive correlated with apoptosis index in the way of pearson analysis. Apoptosis index is positive correlation with model living time、PSV、volume, p<0.05. Conclusion1. Ultrasonography can reveal the morphology and course changes of extracranial vertebral artery correctly in congenital vertebral artery anomaly of children.2. Morphology changes of vertebral artery got by ultrasonography combine with hemodynamic data to evaluate posterior circulation blood supply in congenital vertebral artery anomaly in children have the high appilicative value.3. Studing posterior circulation insufficiency through building up animal model, which is close to vertebrobasilar insufficiency, has the significance both in theory and clinical practise.4. The correlation between apoptosis index and hemodynamic data shows the narrowness and occlusion of vertebral artery are related to apoptosis cell in brain stem, attesting the close relationship for short supply time and cell apoptosis. On the other hand, showing the body’s instinction to keep body natural condition in the way of increasing blood flow velocity and volume to compensate the short supply as models’ living time longer.更多还原