HIV相关脑痴呆BOLD fMRI运动功能成像

目的:应用功能磁共振成像(fMRI)研究正常健康受试者及HIV相关脑痴呆患者的右手运动功能区并且探讨其应用价值。方法:10例HIV相关脑痴呆患者和8例健康受试者,设计右手相关运动功能实验,采取右手抓握运动方法,结合患者情况分析早期认知运动功能损伤的皮质位置区域和激活情况。结果:正常健康受试者右手运动功能区多位于左侧(对侧)初级躯体感觉运动皮层(SMC)、初级运动皮层(M1)、对侧辅助运动(SMA)、躯体感觉相关皮层以及同侧小脑。HIV患者同侧SMC有激活,对侧主要激活区域基本相同,但激活程度减弱、区域范围减小、像素数降低。结论:fMRI是一种检测HIV相关脑痴呆神经系统损伤的有效工具,为临床早期诊断提供了有效的途径。     

不同强度电刺激诱发SⅠ及SⅡ区激活的fMRI研究

目的利用功能磁共振成像技术(fMR I)观察主要躯体感觉区(SⅠ区)和第二躯体感觉区(SⅡ区)在不同强度电刺激时的激活反应,探讨SⅠ区和SⅡ区对于痛觉调控的作用。方法对10名右利手健康志愿者分别施加1倍痛阈、2倍痛阈、3倍痛阈3个不同强度电刺激任务,并对刺激期间的脑功能活动进行全脑fMR I扫描,应用功能性神经图像分析(AFNI)软件包进行后处理以显示SⅠ区和SⅡ区的激活变化。结果在1倍痛阈强度电刺激时,SⅠ区未见明显激活,SⅡ区外侧部表现出较弱的双侧非对称性激活;2倍痛阈电刺激可诱发对侧SⅠ区和双侧SⅡ区内侧部激活,但BOLD信号未见明显增强;3倍痛阈电刺激可使对侧SⅠ区和双侧SⅡ区激活强度和范围明显增大。结论在不同强度电刺激作用下,SⅠ区和SⅡ区分别表现出不同的激活特性,这将有助于理解高级中枢在痛觉调控网络中的不同贡献。     

步进式视觉累加实验(PVSAT)功能磁共振研究

目的:利用功能磁共振成像(fMRI)技术探讨步进式视觉累加实验(PVSAT)在人脑的作用部位及其意义.方法:12例健康志愿者完成以步进式视觉累加实验(PVSAT)作为刺激模式(包括计算、工作记忆和注意力几个方面的认知功能模式)、采用组块设计(block)的fMRI检查,经SPM2软件处理获得脑功能图像.结果:PVSAT试验中健康志愿者的双侧顶上小叶区、顶下小叶区及额上回、额中回可见激活,而优势半球(左侧)较对侧激活区稍大、强度稍高;左侧额下回和扣带回可见激活;双侧枕叶视觉皮层区有明显激活;小脑亦可见少量激活.结论:PVSAT脑内激活区主要在额顶叶,fMRI可显示脑内激活区,对脑功能的深入研究有重要价值.     

中文语言活动区功能磁共振研究

目的　利用BOLD功能磁共振 ,初步探索国人说汉语时大脑语言相关功能区。方法　对 2 2名正常中国人 ,说中文句子状态下进行BOLD磁共振脑功能成像 ,探索其大脑语言活动皮层相关功能区。结果　说中文时激活的脑区包括 :两侧运动区 ,左右侧额下回 ,左右侧颞上回 ,左侧岛叶及左右侧小脑半球。结论　BOLD功能磁共振可显示中文大脑活动相关皮层 ,是无创性研究人类语言的有力武器     

大鼠前爪刺激的体感皮质功能区fMRI研究

应用1.5T MR扫描仪优化适合大鼠动物模型的functional MRI(fMRI)参数,测定其各自条件下大鼠前爪刺激体感皮质功能区的变化.材料和方法:应用1.5T MRI扫描仪对16只Sprague-Dawley雄性鼠进行fMRI检查.前爪刺激大鼠模型采取Block design方式,刺激序列被分成6个30s段落,休息和电刺激状态交替.进行血氧水平依赖测量时改变有效的回波时间(TE),从40～60ms,每10ms为一时间段.根据激活像素的数目和BOLD的最大反应激活像素的幅度来分析.结果:fMRI显示的大鼠前爪刺激的体感皮质激活中心高度集中位于受刺激的前爪对侧半球中线外侧1.5～4.5mm,额极后4～6mm,各TE组信噪比为100%,最佳回波时间为50ms,其产生最多的激活体素和最大的BOLD反应强度,激活的容积为11.5mm3±3.8.结论:fMRI是一种无创伤的定位大鼠前爪刺激体感皮质功能区的检测手段,这项技术的实验研究对发展和检测fMRI技术,深入研究体感皮质区脑功能的变化(如学习、可塑性、病变与修复等)具有重要价值.     

血氧水平依赖功能磁共振成像在累及运动区脑肿瘤中的应用

目的：功能磁共振成像对脑肿瘤术前评估具有重要意义,探讨血氧水平依赖功能磁共振成像（Bold-fMRI）在累及运动通路脑肿瘤中的应用价值。方法：对16例累及皮层运动区的脑肿瘤患者行fMRI检查,另以10例健康者作为对照,2例患者术后复查,fMRI采用双侧交替进行的大拇指对掌运动作为任务刺激。所有数据进行离线后处理,fMRI图像使用基于MATLAB平台下运行的SPM99软件进行处理,观察运动皮层区激活情况。结果：每个患者的健、患侧主运动区（M1）、辅助运动区（SMA）均激活,其中12例患侧M1区信号低于健侧,3例患侧M1区信号高于健侧,1例健侧与患侧M1区信号无明显差别,11例患侧M1区信号移位,8例患者患侧SMA区及健侧M1区的激活程度较健康人增强;2例患者复查显示患侧M1皮层激活范围较术前变小。结论：应用fMRI能显示肿瘤、皮层运动功能区之间的关系,对邻近脑运动功能区脑肿瘤患者术前评估具有重要意义。     

小脑汉字词语处理相关脑区的功能磁共振研究

目的：运用功能磁共振成像（fMRI），以假词为对照，初步探讨小脑在汉字词语语义处理中的作用。并根据Schmahmann小脑皮质的分类法，初步确定在汉字词语语义处理中小脑的激活区域。材料和方法：25例健康、母语为汉语的受试者参加了本实验，其中男性18例，女性7例。年龄在22-30岁，平均为25．7岁。所有受试者均为大学本科以上学历，受试者实验前均接受Snyder和Harris制定的利手确定问卷，得分在40分以上，确定为右利手。采用fMRI技术，模块设计（block-design）的刺激模式，运用听觉呈现的方法，每名受试者参加两组实验：假词实验组及真词实验组。结果：假词实验组激活的脑区包括双侧颞上回、双侧额下回及左侧角回。真词实验组激活的脑区包括双侧颞上回、双侧额下回、双侧辅助运动区、两侧小脑半球、两侧尾状核及右侧丘脑和左侧角回。双侧辅助运动区、两侧小脑半球、两侧尾状核及右侧丘脑仅在真词实验组中被激活。两侧小脑半球激活区域多位于偏后外侧的区域。结论：小脑半球偏后外侧区域（Ⅵ、ⅦB、ⅧA、CrusI、CrusⅡ）是特征性与汉字词语语义处理有关的区域。     

精神分裂症患者词语流畅性作业测验的功能MRI研究

目的　应用功能磁共振成像研究正常人和精神病患者在进行词语流畅作业测验时其额、颞叶皮层激活情况的差异。方法　 8位志愿者和 13名精神分裂症患者接受词语流畅作业测验。受试者执行任务时 ,应用GE 1 5TSignaHorizonLX超导型磁共振仪 ,采集其脑部的血氧水平依赖 功能磁共振成像 (BOLD fMRI)数据。刺激序列被分成 6个时相 ,每个时相 30s ,通过使用Block激活模式 ,即休息和刺激状态交替。结果　对两组额叶、颞叶激活区面积 (包括额上回、额中回及额下回 )和激活区出现比例 (包括颞上回、颞中回及颞下回 )进行比较 ,精神分裂症组左侧额叶激活较正常组的明显减少 ;正常组左侧额叶较右侧有明显增加 ,P <0 0 5。而颞叶各脑回的精神分裂症患者与正常对照组及左右各对应脑回之间激活情况相仿 ,P <0 0 5。结论　fMRI对检测对照组和精神分裂症患者之间完成高级认知作业时的大脑皮层激活差异具有重要价值。     

面部表情识别任务脑活动性别差异的fMRI研究

目的检测与面部表情识别相关脑区的激活部位及特点,分析其性别间差异。资料与方法采用GE1.5 T磁共振扫描仪对22名健康志愿者(男\女各11名,年龄26～37岁)行磁共振功能成像(functional magneticresonance imaging,fMRI),实验任务为事件相关设计的负性、正性及中性面部表情图片识别。采用SPM5软件进行fMRI数据预处理和统计分析。观察有统计学意义的体素所在的脑区及其MNI坐标,记录激活区的激活强度。并记录志愿者执行任务的反应时间和正确率。结果男性志愿者的反应时间明显快于女性(P<0.05);判断正确率无性别间差异(P>0.05)。识别正性表情时,女性相对于男性(女-男)激活增加的脑区包括左侧前额皮层背外侧(BA11)、两侧顶下小叶(BA39、40)、左侧颞下回(BA38)和右小脑;男性相对于女性(男-女)激活增加的脑区包括右侧前额皮层外侧面(BA6、10、44)、两侧楔前叶(BA7、19)、左侧颞上回(BA42)、两扣带回后部(BA24、30)、左海马旁回(BA30)、两小脑后叶和左尾状核。识别负性表情刺激时,女性相对于男性(女-男)激活增加的脑区包括两侧前额皮层背外侧...     

针刺同一经络不同穴位的磁共振脑功能成像对比研究

目的应用磁共振脑功能成像技术比较针刺同一经络不同穴位所引起的不同中枢反应.材料和方法利用BOLD技术观察分别针刺12例志愿者右侧足三里和丰隆穴时脑信号的改变,用SPM2软件分析比较激活脑区的差异.结果针刺足三里时激活的脑区位于左侧海马回、颞中回、颞上回和右侧颞上回、缘上回.针刺丰隆穴激活的脑区位于左侧颞上回、颞中回和右侧颞上回、扣带回、额内侧回、中央旁小叶.结论相同经络的不同穴位针刺后引起的脑激活区不完全相同,两侧颞上回和左侧颞中回可能是针刺右侧足三里和丰隆穴作用的共同神经通路.     

纯音听觉优势半球--fMRI和脑磁图联合研究

目的 利用血氧水平依赖功能磁共振成像（BOLD-fMRI）和脑磁图（MEG）观察正常人在纯音刺激时听觉中枢的兴奋情况及两侧半球的差异。资料与方法 BOLD-fMRI研究对象为30名正常听力志愿者。BOLD-fMRI采用组块设计。声音刺激用140曲1kHz纯音,持续时间500in8,刺激间隔18,刺激施加频率1Hz。MEG检查共有10名正常受试者,采用90dB1kHz纯音刺激,持续时间8ms,刺激间期1s。用等电流偶极（ECD）描述皮质兴奋并将其与自身MRI图像叠加。结果 在BOLD-fMRI研究中,纯音刺激激活两侧听觉中枢和其周围邻近脑区,右侧半球听觉中枢的激活强度明显大于左侧。MEG检查中纯音刺激诱发的主要磁反应波为M100,M100 ECD位于初级听觉中枢预横回。右侧半球M100 ECD比左侧半球偏前、潜伏期短、强度高。结论 纯音刺激激活听觉中枢和周围脑区,右侧半球为纯音刺激时听觉的优势半球。     

电针正常人阴陵泉穴的脑fMRI研究

目的通过功能磁共振成像(fMRI)研究电针右侧阴陵泉和口面部非穴位点时诱发的脑活动区,比较其异同,推测阴陵泉特异性激活区,探讨与临床疗效的相关性。资料与方法采用组块刺激模式,电针右利手健康志愿者的右侧阴陵泉(5名)和面部非穴位点(5名),对全脑行平面回波血氧水平依赖功能磁共振成像(BOLDfM-RI)和高分辨率三维T1解剖像,用SPM2软件进行统计学预处理,然后将统计参数图叠加到三维解剖图像。结果阴陵泉组5名受试者统计学分析后实验显示不同脑区信号升高和/或降低;信号增高见于右枕叶、右海马、双侧第二躯体感觉区、左顶上小叶;信号降低见于双侧颞下回和右楔前叶;信号呈双向变化见于双侧前额叶。面部非穴位组5名显示的脑激活区与之较相似,其中信号增高区域见于双侧中央后回、双侧前额叶、双侧颞上回、双侧岛叶和右枕叶;信号降低区域见于双侧前额叶、双侧枕叶、楔前叶和左顶上小叶。结论电针阴陵泉未见明显特异性脑活动,大脑在针灸阴陵泉促进排尿的临床实践中的作用较局限。     

注意缺陷多动障碍儿童语义工作记忆的功能MRI研究

目的 研究注意缺陷多动障碍（ADHD）儿童在语义工作记忆任务下不同脑区的功能状态。方法 ADHD儿童与正常学龄儿童各9名，分别进行行为学评估和功能MR（MR）扫描，刺激任务采用区组（BLOCK）设计的倒退N计数（N—BACK）模式下语义工作记忆任务。MR扫描采用GE3．0 T MR记录提取阶段大脑的反应。结果 ADHD儿童在语义工作记忆任务下激活普遍低于正常组，在1-BACK任务中双侧额中回、额下回、双侧顶上小叶、顶下小叶、右基底节激活低于正常组，而在2-BACK任务中双侧额中回、额下回、双侧顶上小叶、左侧顶下小叶、右基底节及前扣带回激活低于正常组。结论 ADHD儿童的工作记忆功能区包括双侧背外侧前额叶及双侧顶叶存在功能低下，在高负荷的2-BACK任务下并有执行功能区（前扣带回）的激活降低。     

Cerebral white matter degeneration in frontotemporal dementia detected by diffusion-weighted magnetic resonance imaging

RATIONALE AND OBJECTIVE: Brain tissue damage in frontotemporal dementia (FTD) has never been systematically studied using diffusion-weighted imaging (DWI). We studied FTD patients using DWI to determine whether microstructural changes in white matter can be detected in vivo. MATERIALS AND METHODS: Thirteen FTD patients and 15 aged healthy subjects were studied. Mean diffusivity (MD) abnormalities in 28 white matter regions were visually evaluated. In addition, MD values in 10 white matter regions relative to that in the ipsilateral postcentral gyrus were measured. The results were compared between healthy subjects and FTD patients. RESULTS: The visual rating resulted in a significant MD elevation in FTD patients in the bilateral high superior frontal gyri, right orbitofrontal gyrus, bilateral anterior temporal lobes, and left middle temporal lobe (P < .01, respectively). Relative MD comparison revealed a significant MD elevation in FTD patients in the bilateral high superior frontal gyri, bilateral orbitofrontal gyri, and bilateral anterior temporal lobes (P < .05 after Bonferroni correction, respectively). CONCLUSION: Our results demonstrated white matter MD abnormalities in FTD patients. It was suggested that the observed white matter MD abnormalities are secondary to damage in the overlying cortex.     

Material-dependent activation in prefrontal cortex: working memory for letters and texture patterns--initial observations

PURPOSE: To prospectively evaluate whether a distinction between verbal and nonverbal short-term memory systems, as predicted with the multicomponent working memory model, is reflected in the material-specific patterns of activation in the prefrontal cortex. MATERIALS AND METHODS: Informed written consent was obtained from all participants, and the institutional review board approved the study protocol. Echo-planar MR imaging was performed in 12 healthy subjects (five female and seven male subjects), with a mean age of 23.52 years +/- 2.52 (standard deviation) and a range of 20-29 years. A two-back task was used in the verbal and nonverbal versions. In the first version, letters were used as stimuli, and in the second version, the stimuli were abstract texture patterns. Timing parameters for both versions were the same. Statistical analysis of the functional data involved a fixed-effects general linear model. Regions of activation were identified from specific t-statistic contrasts between baseline and active tasks (corrected for whole-brain multiple comparisons). RESULTS: The following suprathreshold voxels for the verbal condition were observed predominantly in the left hemisphere (middle frontal gyrus, precentral gyrus, middle temporal gyrus, and occipital cortex). Bilateral activations were in inferior frontal gyri, insulae inferior, superior parietal lobules, and cingulate gyri. In the nonverbal condition, suprathreshold voxels were located mostly bilaterally in the following regions: inferior, middle, and medial frontal gyri and inferior parietal lobules. Active regions were also found in the precentral gyrus and precuneate gyrus in the left parietal lobe and the occipital cortex in the right hemisphere. CONCLUSION: Results of this study are consistent with the multicomponent model of working memory.     

语言优势半球及语言相关皮层区的功能性磁共振定位

目的　研究语言优势半球及语言相关皮层区定位的无创性手段。方法　使用血氧水平依赖对比的功能性磁共振脑扫描(fMRI)技术 ,观察、比较了 11例正常志愿者和 7例颞叶癫痫患者在完成组块设计的语言认知任务时的脑区激活图。结果　 11例志愿者语言优势半球位于左侧半球 ,主要语言相关皮层为左侧额叶及双侧楔叶 ;癫痫病人语言优势半球 6例位于左侧 ,1例位于右侧。主要语言相关皮层区为左颞叶及双侧额下回。 7例患者根据fMRI结果进行了颞叶切除治疗 ,术后均未发生语言障碍。结论　癫痫病人的语言相关脑区与正常人有明显的差异。语言认知任务的fMRI检查可无创地对优势半球和语言功能区进行准确定位 ,帮助制定手术计划。可推荐作为癫痫病人进行颞叶切除前的常规定位方法     

利用fMRI研究正常人执行Stroop任务的脑功能网络

目的:利用功能磁共振成像(fMRI)探讨正常人执行汉字Stroop任务时任务相关的激活与去激活脑功能网络。方法:14例正常志愿者接受了Stroop任务的组块式fMRI,扫描序列为平面回波血氧水平依赖(BOLD)序列,利用统计参数图(SPM99)软件进行图像分析。所有检查完毕后,对受试者进行Stroop的行为学测试,记录反应时间及错误数。结果:正常对照组认字试验的反应时间与颜色命名试验之间差异有显著性意义(t=-8.188,P=0.000)。对照状态下,正常人出现后扣带回皮层、中线前额叶皮层、背侧前扣带回的去激活。正常人执行颜色命名任务较认字任务时出现更多脑区的激活,且其激活强度较第1个任务的脑区激活强度增加。执行颜色命名任务时动用了双侧额中回、左侧额上回、左侧额下回及双侧顶叶。结论:本研究进一步证实静息状态下存在大量的神经元活动,其与任务相关的脑功能网络共同维持正常的认知活动。     

Intensity-dependent activation of the primary auditory cortex in functional magnetic resonance imaging

PURPOSE: The purpose of this study was to investigate the activation patterns of the primary auditory cortex in response to varying intensities of pure tone stimuli. METHOD: A 1,000-Hz pure tone stimulus was delivered monaurally to the right ear of 12 normal-hearing right-handed volunteers in 20-second on-off cycles. Stimuli were applied at 20 and 50 dB hearing level (HL) above threshold in 12 subjects and at 0, 20, 40, and 50 dB HL above threshold in 6 subjects. Functional magnetic resonance imaging (fMRI) data were obtained using a 1.5-T scanner and echoplanar imaging. Activated pixels were identified in the transverse temporal gyrus (TTG) of both hemispheres in response to pure tone stimuli at each intensity level using cross-correlation analysis (0.6; P < 0.0001). RESULTS: Of the 24 right and left TTGs imaged (n = 12), activation to pure tone stimuli at 20 and 50 dB HL above threshold was seen in 46% and 79% of TTGs, respectively, with bilateral hemispheric activation in 27% and 64% of subjects, respectively. The mean numbers of activated voxels were 4.0 and 13.0, respectively. Of the 12 right and left TTGs imaged at 0, 20, 40, and 50 dB HL above threshold, activation was seen in 33%, 42%, 58%, and 75% of TTGs, respectively. The mean numbers of activated voxels were 5.8, 3.2, 9.8, and 15.3, respectively. There was a nonsignificant trend toward contralateral (left) dominant TTG activation with increased tone intensity. CONCLUSION: Our results show an increased likelihood of TTG activation, increased TTG activation volume, and increased bilateral hemisphere TTG activation with increasing pure tone intensity. Our results suggest that the primary auditory cortex reflects or is directly involved in the central processing of sound intensity and that varying the intensity of even simple stimuli can alter the patterns of fMRI activation in auditory cortex.     

Cortical damage in Alzheimer's disease estimation in medial and lateral aspects of the cerebrum using an improved mapping method based on diffusion-weighted magnetic resonance imaging

RATIONALE AND OBJECTIVES: A method of estimating and mapping the cortical damage resulting from neurodegenerative diseases based on diffusion-weighted imaging was recently proposed. We improved on this method to visualize the cortical damage in Alzheimer's disease (AD) in the lateral and medial aspects of the cerebral hemispheres and to provide anatomic references. MATERIALS AND METHODS: Damage in the cerebral cortex was estimated based on diffusivity in the subcortical white matter according to a previously published method. A map of subcortical mean diffusivity (MD) was superimposed on the corresponding anatomic image so that the spatial extent of the abnormality could be anatomically localized. The right and left hemispheres were separated to evaluate the medial and lateral aspects of each hemisphere. This method was applied to 10 healthy subjects and 11 AD patients. MDs within 20 cortical regions were visually evaluated and statistically compared between AD and healthy subjects at a significance level of P < .01. RESULTS: In addition to the involvement of the lateral aspects of the bilateral parietal and temporal lobes and clear sparing of the bilateral pericentral regions that were previously reported, significant MD elevation was observed in the medial aspects of the right frontal, bilateral parietal, and right temporal lobes. The extent of MD abnormalities was easily identified by the background anatomic image. CONCLUSIONS: Results suggested that AD damage in the lateral and medial cerebral cortex can be visualized with an anatomic reference using our method.     

基于体素的形态测量学在阿尔茨海默病和轻度认知障碍中的应用价值

目的：应用基于体素的形态测量学（VBM）方法比较阿尔茨海默病（AD）和轻度认知障碍（MCI）患者和健康老年人灰质体积的不同,探讨VBM方法在AD、MCI诊断中的应用价值。方法：本研究包括10例AD患者（AD组）、9例MCI患者（MCI组）、10例老年健康志愿者（健康对照组）,检查系列包括头常规轴面T2WI、T1WI、轴面FLAIR、矢状面T1WI,全脑3D-SPGR。应用VBM方法处理数据,把脑组织分割成灰质、白质和脑脊液,最后应用两样本t检验两两比较灰质体积改变。结果：AD组与正常对照组脑灰质体积比较：AD组大脑皮层灰质体积弥漫减少,激活区域几乎分布整个大脑半球,以两侧内侧颞叶（海马、梨状皮层、内嗅皮层）为著。右侧海马减少的体素总数为2358个,左侧海马减少的体素总数为2967个,前后扣带回体素明显减少;MCI组与正常对照组比较：MCI组灰质减少的区域依然较多,但与AD和对照组相比,激活区域明显减少。其中最明显的是内侧颞叶内嗅皮层、海马旁回区域,右侧体素减少总数为1368,左侧1135;MCI组和AD组的比较：MCI组较AD组灰质减少的区域更多,内侧颞叶和海马区域基本没有激活区域,较明显的激活区域位于双侧额顶颞叶、扣带回。双侧尾状核头部和左侧丘脑亦有较明显激活,而豆状核没有明显激活。结论：内侧颞叶和海马体积减小是评价AD和MCI最敏感的区域,VBM可以有效评价灰质体积的改变。