Surface-Based Morphometry of Human Brain: Intra-Individual Comparison Between 3T and 7T High Resolution Structural MR Imaging

Objective High resolution structural MR imaging can reveal structural characteristics of cerebral cortex and provide an insight into normal brain development and neuropsychological diseases. The aim of this study was to compare cortical structural characteristics of normal human brain between 3T and 7T MRI systems using surface-based morphometry based on high resolution structural MR imaging. Methods Twelve healthy volunteers were scanned by both 3T with 3D T1-weighted fast spoiled gradient recalled echo (3D T1-FSPGR) sequence and 7T with 3D T1-weighted magnetization-prepared rapid gradient echo (3D T1-MPRAGE) sequence. MRI data were processed with FreeSurfer. The cortical thickness, white and gray matter surface area, convexity, and curvature from data of 3T and 7T were measured and compared by pairedt-test. Results Measurements of mean cortical thickness, total white matter surface area and gray matter surface area of 3T were larger than those of 7T (left hemisphere:P=0.000, 0.006, 0.020 respectively; right hemisphere:P=0.000, 0.000, 0.000 respectively). Surface-based morphometry over the whole brain demonstrated both reduced and increased measurements of cortical thickness, white and gray surface area, convexity, and curvature at 7T compared to 3T. Conclusions Inconsistency of brain structural attribute between 3T and 7T was confirmed, and researchers should be cautious about data when using ultrahigh field MR system to investigate brain structural changes.     

Continuous representation of human portraits and natural scenery in human ventral temporal cortex: evidence from functional magnetic resonance imaging

Background Functional magnetic resonance imaging (fMRI) has become a powerful tool for tracking human brain activity in vivo. This technique is mainly based on blood oxygenation level dependence (BOLD) contrast. In the present study, we employed this newly developed technique to characterize the neural representations of human portraits and natural sceneries in the human brain. Methods Nine subjects were scanned with a 1.5 T magnetic resonance imaging (MRI) scanner using gradient-recalled echo and echo-planar imaging (GRE-EPI) pulse sequence while they were visually presented with 3 types of white-black photographs: natural scenery, human portraits, and scrambled nonsense pictures. Multiple linear regression was used to identify brain regions responding preferentially to each type of stimulus and common regions for both human portraits and natural scenery. The relative contributions of each type of stimulus to activation in these regions were examined using linear combinations of a general linear test. Results Multiple linear regression analysis revealed two distinct but adjacent regions in both sides of the ventral temporal cortex. The medial region preferentially responded to natural scenery, whereas the lateral one preferentially responded to the human portraits. The general linear test further revealed a distribution gradient such that a change from portraits to scenes shifted areas of activation from lateral to medial. Conclusions The boundary between portrait-associated and scenery-associated areas is not as clear as previously demonstrated. The representations of portraits and scenes in ventral temporal cortex appear to be continuous and overlap.     

FUNCTIONAL MAGNETIC RESONANCE IMAGING STUDY OF THE BRAIN IN PATIENTS WITH AMYOTROPHIC LATERAL SCLEROSIS

Objective To study the activation changes of the brain in patients with amyotrophic lateral sclerosis （ALS） while executing sequential finger tapping movement using the method of blood oxygenation level dependent （BOLD） functional magnetic resonance imaging （tMRI）. Methods Fifteen patients with definite or probable ALS and fifteen age and gender matched normal controls were enrolled. MRI was performed on a 3.0 Tesla scanner with standard headcoiL The functional images were acquired using a gradient echo single shot echo planar imaging （EPI） sequence. All patients and normal subjects executed sequential finger tapping movement at the frequency of 1-2 Hz during a block-design motor task. Structural MRI was acquired using a three-dimensional fast spoiled gradient echo （3D-FSPGR） sequence. The tMRI data were analyzed by statistical parametric mapping （SPM）. Results Bilateral primary sensorimotor cortex （ PSM）, bilateral premotor area （ PA）, bilateral supplementary motor area （SMA）, bilateral parietal region （ PAR）, contralateral inferior lateral premotor area （ ILPA）, and ipsilateral cerebellum showed activation in both ALS patients and normal controls when executing the same motor task. The activation areas in bilateral PSM, bilateral PA, bilateral SMA, and ipsilateral cerebellum were significantly larger in ALS patients than those in normal controls （ P 〈 0.05 ）. Extra activation areas including ipsilateral ILPA, bilateral posterior limb of internal capsule, and contralateral cerebellum were only detected in ALS patients. Conclusions Similar activation areas are activated in ALS patients and normal subjects while executing the same motor task. The increased activation areas in ALS patients may represent neural reorganization, while the extra activation areas in ALS patients may indicate functional compensation.     

快速液体衰减反转恢复(FAST FLAIR)序列在脑部疾病诊断中的应用价值

目的:探讨快速液体衰减反转恢复(FAST FLAIR)序列在脑部疾病诊断中的应用价值。方法:108例脑缺血性疾病患者同时行T2加权FSE序列和FLAIR序列检查。结果:FLAIR序列显示异常信号病灶426个,T2加权FSE序列显示异常信号病灶324个,而且前者比后者边界显示清晰。结论:FLAIR序列在发现病灶数目,病灶与周围脑实质的对比度明显优于T2加权FSE序列。FLAIR序列在脑缺血性疾病诊断中的有较高的价值。     

功能性磁共振成像技术在老年人术后认知功能障碍中的应用

功能磁共振成像(fMRI)是通过一定的刺激使大脑皮质各功能区在磁共振设备上成像的方法,可以反映大脑的神经活动水平,对大脑的神经活动能准确地进行功能检测,并在活体人脑定位各功能区。fMRI是一种全新的对人的认知功能进行评价的影像学手段。通过fMRI对术后认知功能障碍患者脑功能区改变的研究,可为术后认知障碍的临床早期预防、诊断和治疗提供客观和直观的影像学依据。     

fMRI在蒙医针灸和rTMS治疗脑卒中后语言功能障碍恢复方面的疗效评价

脑的功能磁共振(fMRI)是利用磁共振成像生成反映脑血流变化的图像.它主要以实时无辐射的探测技术对特定的大脑皮层区域进行扫描,以此来观察大脑神经网络情况.血氧水平依赖功能磁共振主要是神经元活动引起血液动力的改变,是目前功能磁共振在临床研究方面应用广泛的一个技术.当大脑神经活跃时,其附近的血流及血流耗氧增加,顺磁性的去氧...     

Brain and spinal tumors: magnetic resonance imaging using gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA)

Magnetic resonance imaging (MRI) was performed in 17 patients (with 24 tumors) before and after intravenous administration of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). Contrast enhancement was seen in 16 patients. The image pattern of enhancement is the same as that of CT. With 0.1 mmol/kg intravenous bolus injection, the best enhancement can keep for one hour. In brain, the degree of enhancement was greater than that seen with CT in 7 tumours, equal to it in 12 tumors, and less in zero. MRI distinguished between tumour and peritumoral edema to the same extent as did CT. No side-effects were encountered and there was no significant change in regular urine and blood tests after administration of Gd-DTPA. T1-weighted images of spin echo pulse sequence are the best pulse sequence to observe the enhancement. Gd-DTPA is of considerable value in MRI of the brain and spine.     

磁共振液体抑制反转恢复技术在颅脑疾病中的应用

目的评价液体抑制反转恢复 (FLAIR)序列在颅脑疾病中临床应用价值。方法对 6 3例颅脑疾病患者行常规FSET1、T2序列及FLAIR序列扫描。比较这些序列在显示颅脑病变的差异。结果在 6 3例颅脑疾病中 ,FLAIR像共显示病灶 14 7个 ,而T2加权像只显示 10 6个。有 4 1个病灶仅在FLAIR图像中显示 ,95个病灶的内部结构、边界在FLAIR像较T2 像显示清晰。结论FLAIR像显示颅脑中邻近脑沟、脑室旁 ,脑室及脑池内等部位病变的边界、大小、范围及内部结构优于T2 加权像。     

重T_2在颅脑常见肿瘤中的应用(附37例分析)

为探讨用MR重T_2加权显示脑部肿瘤的临床应用价值。对37例病人共进行了41次磁共振成像。应用快速自旋回波(FSE)无脂肪抑制的重T_2加权成像技术.结果在原发性颅内肿瘤中,重T_2加权均能显示瘤体内部组织的结构及瘤体周边组织的病变。在较大的转移瘤中显示了内部结构及瘤体周边组织病变。因此提示了重T_2加权能更好的显示肿瘤的内部结构及其周边组织的病变。与常规MRI检查结合可以提供更多的肿瘤内部信息,提高诊断的准确性。方法简单,安全。     

危重脑梗死患者颅脑MR检查的序列优化

目的探讨在满足诊断的前提下,完成危重脑梗死患者颅脑MR检查的最佳方案。方法对临床拟诊为脑梗死的90例危重患者（全部病例均经CT检查已除外急性出血）应用半傅里叶采集自旋回波序列（half-fourier acquisition SE-HF）、半傅里叶采集单次激发快速自旋回波序列（half-fourier acquisition singo-shot turbo-SE,HASTE）和平面回波成像序列（echo planar imaging,EPI）完成颅脑的T1WI、T2WI和DWI检查,对部分躁动患者辅以制动措施。结果 88例患者约在2分钟完成颅脑MR检查,满足了临床诊断的要求。结论超快速的颅脑MR检查是危重脑梗死患者进行颅脑MR检查的前提,而采取合理的序列组合是实现超快速颅脑MR检查的重要手段。     

全麻状态下静脉麻醉药丙泊酚对大脑功能连结性的影响

 目的  应用静息态功能磁共振(rest state functional magnetic resonance imaging,rs-fMRI)成像技术观察深度麻醉下静脉麻醉药丙泊酚对大脑功能连结性的影响。方法  6位在术中磁共振手术室行经蝶垂体瘤切除术的神经外科患者,采用丙泊酚靶控输注(效应室浓度4 μg/mL)进行麻醉诱导并维持。分别在患者处于清醒、麻醉和麻醉下进行疼痛刺激三种状态时应用3.0 T场强磁共振仪进行扫描。获取的影象学资料应用AFNI软件分析大脑默认网络,体感运动网络和疼痛相关网络的功能连结性,并用SPSS统计软件进行统计分析。结果  种子体素相关分析法结果显示,与清醒状态相比,丙泊酚导致在外科麻醉水平大脑默认网络、躯体运动感觉皮层以及疼痛相关脑区岛叶皮层的脑功能连接显著下降,表现为扣带回、内侧前额叶、岛叶等脑区被抑制(P<0.01)。疼痛刺激后在躯体运动感觉皮层及疼痛相关脑区的功能连接呈现部分恢复,表现为右侧舌回、梭状回、岛叶及扣带回区出现不同程度的激活(P<0.01);而默认网络的功能连接则进一步下降(P<0.01)。结论  在外科麻醉水平,丙泊酚导致大脑各脑区功能连接减弱,提示可能与意识水平降低相关。扣带回、岛叶以及内侧前额叶可能是丙泊酚中枢作用靶点。而疼痛刺激虽可恢复部分脑区功能连结性,但重要脑区的功能连结性仍显著下降。     

FLAIR与T2WI序列对脑转移瘤的对比研究

目的对比研究FLAIR序列与T2加权序列在脑转移瘤诊断中的敏感性.方法对63例脑转移瘤患者行FLAIR及快速T2加权序列扫描,比较FLAIR序列与T2加权序列显示脑转移瘤的差异.结果 （1）在63例患者中,FLAIR上显示病灶306个,T2加权显示病灶238个,FLAIR较T2加权像在显示脑转移瘤的病灶数目方面敏感,差异有统计学意义（P〈0.05）,尤其是位于皮层、皮层下区及邻近脑沟、脑室旁的病灶;（2）在238个病灶中,T2WI与FLAIR在显示每个病灶大小、边界范围差异无统计学意义（P〉0.05）,而对病灶的内部结构及周边水肿差异均有统计学意义（P〈0.01）.结论 FLAIR像在检出转移瘤的病灶数目及显示瘤灶的周边水肿及内部结构均优于T2加权像,可作为常规脑转移瘤检查的补充序列.     

Laterality of brain areas associated with arithmetic calculations revealed by functional magnetic resonance imaging

Asymmetry of bilateral cerebral function, i.e. laterality, is an important phenomenon in many brain actions : arithmetic calculation may be one of these phenomena. In this study, first, laterality of brain areas associated with arithmetic calculations was revealed by functional magnetic resonance imaging (fMRI). Second, the relationship among laterality, handedness, and types of arithmetic task was assessed. Third, we postulate possible reasons for laterality. Methods Using a block-designed experiment, twenty-five right-handed and seven left-handed healthy volunteers carried out simple calculations, complex calculations and proximity judgments. T1 WI and GRE-EPI fMRI were performed with a GE 1.5T whole body MRI scanner. Statistical parametric mapping ( SPM99 ) was used to process data and localize functional areas. Numbers of activated voxels were recorded to calculate laterality index for evaluating the laterality of functional brain areas. Results For both groups, the activation of functional areas in the frontal lobe showed a tendency towards the nonpredominant hand side, but the functional areas in the inferior parietal lobule had left laterality. During simple and complex calculations, the laterality indices of the prefrontal cortex and premotor area were higher in the right-handed group than that in the left-handed group, whereas the laterality of the inferior parietal lobule had no such significant difference. In both groups, when the difficulty of the task increased, the laterality of the prefrontal cortex, premotor area, and inferior parietal lobule decreased, but the laterality of posterior part of the inferior frontal gyrus increased. Conclusions The laterality of the functional brain areas associated with arithmetic calculations can be detected with fMRI. The laterality of the functional areas was related to handedness and task difficulty.     

Mapping cortical areas associated with Chinese word processing using functional magnetic resonance imaging

Objective To identify the cortical areas engaged during Chinese word processing using functional magnetic resonance imaging.(fMRI)and to examine the reliability and reproducibility of fMRI for localizaiton of functional areas in the human brain.Methods FMRI data were collected on 8 young,right-handed,native Chinese speakers during performance of Chinese synonym and homophone judgment tasks on two different clinical MRI systems(1.5T GE Signa Horizon and 1.5 T Siemens Vision).A Cross correlation analysis was used to statistically generate the activation map.Results Broca‘s area,Wernicke‘s area,bilateral extrastriate,and ventral temporal cortex were significantly activated during both the synonym and homophone activities.There was essentially no difference between results acquired on two different MRI systems.Conclusions FMRI can be used for localizing cortical areas critical to Chinese language processing in the human brain.The results are reliable and well reproducible across different clinical MRI systems.     

针刺即时效应对急性脑梗死患者脑功能成像的影响

【目的】探讨针刺治疗急性脑梗死的作用机理。【方法】应用fMRI脑功能成像评价针刺内关穴的即时效应,对急性脑梗死患者及健康人相关脑功能区兴奋性的影响,对15例急性脑基底节区梗死患者和15例健康志愿者,针刺双侧内关穴,分别于针刺前、后行静息态fMRI脑功能成像扫描,获取两组被试静息态的fMRI数据,通过后处理软件得到脑梗死患者和健康对照组不同脑区的脑功能激活图像。【结果】患者针刺后,在右侧枕叶和左侧顶叶存在正激活,而左侧运动区有负激活。健康人针刺后,在双侧顶叶和枕叶出现正激活,在双侧额叶出现负激活。【结论】针刺内关穴对脑梗死患者和正常人的脑功能活动激活区域表现存在差异,提示针刺内关穴对机体病理与生理状态下fMRI脑功能成像影响不同。     

运动准备和执行的事件相关功能磁共振研究

目的:应用事件相关功能磁共振成像技术研究参与运动准备和执行的脑区的激活特点.方法:应用事件相关功能磁共振成像技术记录12名右利手健康受试者在序列手指运动过程中运动准备与运动执行大脑皮层的功能活动.采用美国威斯康辛医学院AFNI软件包进行每个像素的血氧变化分析,作出与运动准备和运动执行有关的脑激活图.结果:与运动准备有关的激活主要集中在双侧运动前区(PMC)前部,双侧后顶叶(PPC)后部;与执行有关的激活区主要集中在对侧初级运动区(M1),双侧辅助运动区(SMA)本部;而双侧辅助运动区前部、双侧运动前区后部在运动准备与执行过程中均有激活.结论:人脑内与运动相关的脑区功能并非单一.     

正常成人脑部皮层下灰质结构的3D pc-ASL灌注成像的可重复性

目的 研究正常成人脑部皮层下灰质结构3D假连续快速自旋回波动脉自旋标记(3D pc-ASL)灌注的可重复性.方法 对8例健康成年人进行脑部3D pc-ASL序列及3D结构像扫描,同一时间间隔一周后再次进行扫描.对3D结构像进行皮层下灰质结构(壳核、苍白球、尾状核、丘脑、杏仁核、海马)分割,并将3D pc-ASL进行计算生成脑血流(CBF)图,基于分割后的图像及CBF图进行皮层下灰质结构CBF值提取.对于两次测量结果采用组内相关系数(ICC)及Bland-Altman图分析.结果 皮层下灰质结构的ICC值为0.80-0.93,均值为0.88±0.04.Bland-Altman图形分析证实所有皮层下灰质结构对应的点均位于95％一致性界限内.结论 3D pc-ASL是一个可靠的评估脑部皮层下灰质核团灌注的序列.     

健康老年人大脑皮质机能定位的临床CT研究

目的：探讨在CT图像上对大脑皮质机能区简单而准确的定位方法。方法：随机抽取50例健康老年人的CT图像,以大脑表面沟回为标志辨认大脑皮质机能区。结果：大脑表面沟回为标志辨认大脑皮质机能区。结果：大脑表面沟回在健康老年人CT图像上显示清楚,易于辨认。中央沟、外侧沟、额上沟、顶枕沟、距状沟、脑室、脑池可作为定位大脑皮质机能区的主要解剖标志,并以8个典型CT轴位图像表示其结果。结论：大脑表面沟回是在CT图像上识别健康老年人大脑皮质机能区的一种标记。     

磁共振动态增强扫描对肾癌诊断价值的探讨

目的:研究动态增强磁共振扫描对肾癌的诊断价值和肾癌的强化特点。方法:对35例肾癌患者行SE序列T1WI,TSE序列T2WI,T1WI,T2WI压脂像,TFE序列动态增强及SE序列延迟T1WI扫描。计算并比较不同序列肿瘤-肾实质对比-噪声比(CNR)。计算增强后肾皮质、髓质、肿瘤的信号强度,并绘出曲线,分析各自不同的强化特点。结果:共检出肾癌35例,直径2～12cm。增强后各个序列图像CNR均较增强前有统计学意义(P<0.05),动态增强序列中肿瘤-肾髓质对比在140s左右最明显。结论:磁共振动态增强扫描是诊断肾癌的有效方法。     

外关穴配伍支沟穴皮部浅刺和常规针刺激活脑区的fMRI比较研究

运用fMRI探讨外关穴配伍支沟穴皮部浅刺激和常规深度刺激激活脑功能区的特点。方法：8名健康志愿者先后进行外关穴配伍支沟穴皮部浅刺激和常规深度刺激，运用GE公司1．5T超导核磁共振系统完成脑部fMRI扫描，基于感兴趣区（ROI）观察局部脑区的功能变化，用统计学方法比较激活几率、激活点数和激活强度。结果：两种方法对左右不同脑区都有不同程度的激活，统计表明无显著性差异（P〉0．05）；位有趋势表明，皮部浅刺相对集中激活额叶，常规针刺相对集中激活枕叶、小脑和基底节区。结论：外关穴配伍支沟穴皮部浅刺激和常规深度刺激对脯功能区的激活没有显著差异，但二者有着作用倾向的不同。表明两种层次的针刺刺激产生的效应，与脑部整合作用相关。