【作者】 李强；

【导师】 王玮； 崔光彬； 王亚蓉；

【作者基本信息】 第四军医大学 ， 影像医学与核医学， 2008， 硕士

【摘要】 目的:1、探讨伏隔核3.0T磁共振容积扫描的最佳扫描参数。2、利用3.0T磁共振探寻显示伏隔核的最佳方式。3、利用3.0T磁共振分析正常伏隔核体积双侧差异及性别差异。4、研究海洛因成瘾者在静息态下默认脑功能网络与健康者的差异。方法:1、健康志愿者72人,平均分为12组。利用T1WI三维快速扰相梯度回波序列,在其它参数固定的情况下,分别采用4个不同准备时间与3种矩阵组合成的12种方案对伏隔核进行容积扫描。测量伏隔核与其邻近脑白质的对比噪声比(CNR)并进行分析。2、对32名健康志愿者进行常规及容积扫描。将容积扫描图像进行不同角度重建,分为12组。对各组重建伏隔核图像进行打分评价并分析。3、健康志愿者42人(男24,女18),年龄范围18-55岁,中位数年龄25岁,利用磁共振对伏隔核进行常规扫描、冠状位容积扫描。在容积扫描图像上对伏隔核分割并进行体积测量,比较双侧体积差异及性别间差异。4、海洛因成瘾者14人和与之年龄、性别、体重、左右利手及受教育程度均相配的健康者14人接受3.0T磁共振扫描。所得MRI数据以腹前侧扣带回(vACC)为感兴趣区(ROI)构建全脑的功能网络连接图并比较成瘾组与对照组的差别。结果:1、在所有组中第1组所得的图像CNR最高(P<0.05)。当矩阵为256×256时,第1组图像CNR最高(P<0.05);当矩阵为342×342时,第5-8组之间不存在统计学差异;当矩阵为512×512时,第9组的图像CNR分别最高(P<0.05)。2、男女性别间分值差异无统计学意义,与前后连合连线垂直的90°组与其它角度组间的差异均有统计学意义(P<0.05)。3、所有志愿者以及男、女性志愿者伏隔核平均体积均右侧大于左侧(P<0.001)。男女之间伏隔核总体积不存在统计学差异(P>0.05)。4、以vACC为ROI建立的全脑连接图,成瘾者功能连接图较健康被试活动增强的区域有:双侧岛叶、左侧海马、右侧海马旁回、双侧舌回、额下回、颞上回;成瘾者较健康被试功能连接图活动减弱的区域有:后扣带回、左侧背外侧前额叶皮层、双侧楔前叶、小脑、胼胝体下回、右侧伏隔核。(P<0.01)结论:1、利用3.0T磁共振三维快速扰相梯度回波序列扫描伏隔核时,在TR=8.1ms /TE=3.6ms /FOV=24cm×19.6cm /层厚=1.4mm /层间距=-0.7mm /翻转角=20°/NEX=2的情况下,较合适的矩阵应为342×342,准备时间为350-500ms之间。2、3.0T磁共振可以较好显示伏隔核,扫描伏隔核最佳方案应为垂直于前后连合连线的冠状位扫描。3、健康成人右侧伏隔核体积大于左侧,性别之间伏隔核总体积无明显差异。4、成瘾者与健康被试在静息态下与vACC有功能连接的区域存在明显差异。静息态fMRI研究为海洛因成瘾机制的研究提供了新的方向。更多还原

【Abstract】 Objective1. To explore the optimal 3.0T MR Volume Scan Parameter of Nucleus Accumbens.2. To search for the best way in displaying nucleus accumbens by means of 3.0T MRI scanner.3. To measure the volume of nucleus accumbens by means of 3.0T MR scanner and analyze the difference between two sides and between males and females.4. To investigate the differences between heroin addicts and normal controls in the default mode functional connectivity in the resting-state brain.Methods1. 72 healthy volunteers ,divided into 12 groups,undertook MR scan using 3D fast spoiled gradient recall (3D-FSPGR)sequence.With the other parameters fixed,4 different preparation time and 3 matrix were combined respectively contributing to 12 protocols.Contrast-noise ratio (CNR) of nucleus accumbens and nearby white matter was measured and analyzed.2. 32 healthy volunteers underwent the routine and volume MR imaging examination of brain and then the volume images were reconstructed and classified into 12 groups based on the different reconstructing angles. The reconstructed images of each group were scored according to the degrees of whether the nucleus accumbens was completely displayed or not.3. 42 healthy volunteers(24males and 18femals),ranging from 18 years to 55 years ,medial age 25 years old, underwent the routine and volume MR imaging examination of the brain. The volume of nucleus accumbens on both sides was measured and the difference between both sides and different gender was analyzed.4. 28 volunteers participated this study ,14 of whom were heroin addicts and 14 of whom were healthy adults.The two groups were matched in age,gender,weight,right handedness and education.Both groups undertook MR scanning and the data was acquired and processed.The ventrolateral anterior cingulate cortex was defined as the region of interest(ROI) based on which the functional connectivity map of the whole brain was built and compared.Results1. Of all the groups ,the CNR of the first group was the best(P<0.05).When the matrix was 256×256, the CNR of the first group was the best(P<0.05).When the matrix was 342×342, no significant statistical difference was found among the fifth to the eighth group(P>0.05). When the matrix was 512×512, the CNR of the ninth group was the best(P<0.05).2. Between male and female, the display of nucleus accumbens had no statistical significance, but it did have between the group with the reconstructing angle 900 and other groups.3. Among males ,females or total volunteers the average volume of nucleus accumbens on the right side is significantly larger than it is on the left (P<0.001).No significant difference of the total volume between males and females was found(P>0.05).4. The vACC showed more significant resting-state connectivity with the following regions in the heroin addicts group than in the normal group: insula bilaterally,left hippocampus, right parahippocampal gyrus, lingual gyrus bilaterally,inferior frontal gyrus bilaterally and superior temporal gyrus bilaterally.And it showed more significant resting-state connectivity with the following regions in the normal group than in the heroin addicts group:PCC, left DLPFC, precuneus bilaterally,cerebellum bilaterally,subcallosal gyrus bilaterally and right nucleus accumbens.(P<0.01)Conclusions1. To acquire excellent images of nucleus accumbens by means of 3D-FSPGR with 3.0T MR scanner, the proper matrix and preparation time should be 342×342, 350-500ms when the other parameters is TR=8.1ms /TE=3.6ms /FOV=24cm×19.6cm /slice thickness=1.4mm /spacing=-0.7mm /flip angle=20°/NEX=2.2. 3.0T MRI can display nucleus accumbens effectively and excellently. The best method to show the nucleus accumbens is the coronal scan, its plane should be vertical to the line between anterior-posterior commissure.3. Among healthy adults,the volume of nucleus accumbens on the right side is larger than it is on the left. There is no significant difference of total volume of nucleus accumbens between males and females.4. Significant difference exists between heroin addicts and healthy adults in functional connectivity maps based on vACC in the resting-state brain.The method of resting-state brain fMRI study shed light on the study of addiction mechanism.更多还原