BOLD技术与皮质电刺激定位语言功能区的比较

目的:将语言BOLD与术中皮质电刺激作点对点比较,评价其对语言功能区定位的准确性.材料和方法:12例左侧大脑半球近语言功能区手术病例术前采用词语联想任务进行BOLD扫描,融合在导航序列上进行神经导航手术.在局麻下进行术中皮质电刺激,与导航影像对应,采用完全吻合或相邻1cm以内两种不同的标准来比较BOLD激活区与电刺激阳性区的关系.结果:12例病人共刺激了145个点,其中阳性点27个.与ESM比较,以完全重叠为标准,BOLD敏感性48.1%,特异性83.1%;以相距小于1cm为标准,BOLD敏感性88.9%,特异性75%.良性或低级别肿瘤(9例)BOLD敏感性(95.2%)特异性(80.4%)均高于高级别恶性肿瘤(3例)(敏感性66.7%,特异性68.6%).结论:词语联想任务的BOLD-fMRI与ESM结果有较好的吻合,显示出一定的临床应用价值.     

Cortical mapping by functional magnetic resonance imaging in patients with brain tumors

The aim of our study was to establish the effectiveness of the functional MRI (fMRI) technique in comparison with intraoperative cortical stimulation (ICS) in planning cortex-saving neurosurgical interventions. The combination of sensory and motor stimulation during fMRI experiments was used to improve the exactness of central sulcus localization. The study subjects were 30 volunteers and 33 patients with brain tumors in the rolandic area. Detailed topographical relations of activated areas in fMRI and intraoperative techniques were compared. The agreement in the location defined by the two methods for motor centers was found to be 84%; for sensory centers it was 83%. When both kinds of activation are taken into account this agreement increases to 98%. A significant relation was found between fMRI and ICS for the agreement of the distance both for motor and sensory centers (p=0.0021–0.0024). Also a strong dependence was found between the agreement of the location and the agreement of the distance for both kinds of stimulation. The spatial correlation between fMRI and ICS methods for the sensorimotor cortex is very high. fMRI combining functional and structural information is very helpful for preoperative neurosurgical planning. The sensitivity of the fMRI technique in brain mapping increases when using both motor and sensory paradigms in the same patient.     

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.     

信号式功能性电刺激对脑卒中偏瘫患者上肢运动功能和功能独立性的影响

目的:探讨信号式功能性电刺激对脑卒中偏瘫患者早期运动功能的影响。方法:48例脑卒中患者随机分为4组,即信号式功能性电刺激治疗组(简称信号组)、传统低频电刺激治疗组(简称低频组)、肌电反馈电刺激治疗组(简称肌电组)以及无电刺激治疗组。入组后,所有患者给予常规康复治疗,包括内科常规药物治疗和基础的康复治疗。此外,各电刺激组患者予以相应的电刺激治疗。分别在治疗前、治疗后20天时采用简化Fugl-Meyer运动功能评定(上肢部分)和功能综合评定量表(FCA)对患者功能进行评定并对结果进行统计分析。结果:治疗前各组两项评分均未见显著性差异(P>0.05)。治疗后20天时,各组上肢运动功能都有不同程度恢复,但肌电组、低频组、信号组与治疗前比较差异具有统计学意义(P<0.05);无电刺激治疗组与治疗前比较差异不显著(P>0.05)。治疗20天后,肌电组、信号组简化Fugl-Meyer运动功能评定(上肢部分)和FCA评分与无电刺激组、低频组比较均有显著性差异(P<0.05),但信号组与肌电组相比差异无统计学意义(P>0.05)。结论:信号式功能电刺激促进脑卒中患者上肢运动功能和FCA恢复的效果近似于肌电生物反馈电刺激,但好于国产低频电刺激和无电刺激。     

脑肿瘤患者术前手运动区的功能MRI

目的：探讨应用功能ＭＲＩ（ｆＭＲＩ）研究脑肿瘤患者手运动区（ＨＲＡ）的结构和功能变化特征。材料和方法：２２例位于或邻近实级运动皮质肿瘤患者采用单次激发ＧＲＥ－ＥＰＩ序列采集Ｔ＾＊２Ｗ图像,共３个周期即６个时相,每个周期包括手指对掌运动激发的１０幅活动图像和１０幅静止图像。经离线工作站重建获取减影后的差别图像,设定ＲＯＩ,描绘动态时间－信号强度曲线,测量信号强度（ＳＩ）上升百分率。结果：８例ＨＲＡ呈局限分布,１４例呈弥漫分布。肿瘤实体的边缘与ＨＲＡ活动中心的最短距离为０．３￣２．８ｃｍ。有５例患者在肿瘤内见到高信号区。肿瘤侧ＳＩ上升百分率为１．５％￣３％,正常侧ＳＩ上升百分率为２．５％￣１０％,结论：对位于或邻近初级运动皮质脑肿瘤患者,功能ＭＲＩ为术前手术计划的制定提供了一种非侵袭性而有效的方法。如果肿瘤实体的边     

Minimum detectable change in motor and prefrontal cortex activity over repeated sessions using 3T functional MRI and a block design

Purpose

To determine the minimum detectable change (MDC) in functional magnetic resonance imaging (fMRI) measurements of brain activity over repeated sessions with 95% confidence using a block design of tasks.

Materials and Methods

Fourteen individuals participated in three sessions on different days during which four scans each of a motor task and working memory task were performed. Using a region‐of‐interest analysis of variance, we calculated the MDC in the volume of activated primary sensorimotor cortex (for motor) and dorsolateral prefrontal cortex (for working memory), as well as the percent increase in MR signal and the center and location of maxima of the activated voxels.

Results

The MDC of activated volume was 5.0–8.8 cm³, and the MDC of percent increase in signal from baseline during tasks was 0.3%–0.6%. The MDC of the center of mass of activity was 3–4 mm, compared to 6–10 mm for the location of maxima.

Conclusion

fMRI measurements that quantify the strength of activity in response to tasks and centers of mass offer sensitive measurements of change over repeated imaging sessions. fMRI can be used for serial investigations of individual participants using simple motor and cognitive tasks using a simple block design. J. Magn. Reson. Imaging 2008;28:1055–1060. © 2008 Wiley‐Liss, Inc.     

原发性闭角型青光眼不同频段低频振幅的静息态功能磁共振研究

目的：应用静息态功能磁共振(rs-fMRI)分析原发性闭角型青光眼(PACG)患者不同频段(slow-4：0.027~0.073 Hz, slow-5：0.01~0.027 Hz)大脑低频振幅(ALFF)值改变。方法40例 PACG 患者及36例年龄、性别匹配的正常健康对照(HC)均接受 rs-fMRI 检查,应用 rs-fMRI 数据处理助手(DPARSF)对数据进行预处理。Statistical Parametric Mapping (SPM8)2因素水平重复方差分析比较 PACG 及 HC 组组间效应以及 slow-4,slow-5频段间效应。随后,两样本 t 检验分别比较 PACG 组及 HC 组2个频段 ALFF 值差异并分析差异脑区 ALFF 值与临床参数的相关性。结果频段间结果显示右侧尾状核、左侧眶部额下回 slow-5频段的 ALFF 值较 slow-4频段高(P <0.05,FDR 校正)。与 HC 组相比,楔前叶、楔叶、双侧舌回、双侧枕中回、双侧距状裂、双侧中央后回、右侧中央前回、右侧颞中回、右侧额中回、双侧顶上小叶、右侧中央旁小叶、左侧顶下小叶 ALFF 减低;PACG 组 ALFF 值增高的脑区包括左侧颞下回、左侧颞上回、左侧小脑后叶、双侧海马旁回、左侧额下回、右侧边缘叶、右侧岛叶、后扣带回(P <0.05, FDR 校正)。此外,笔者发现 slow-4、slow-5频段均能检出 PACG 患者异常脑功能活动区。结论PACG 患者存在视觉以及视觉以外相关脑区神经元活动异常,slow-4、slow-5能从不同的角度发现异常脑区,为进一步探究 PACG 的神经病理机制提供了新思路。     

Multislice interleaved excitation cycles (MUSIC): An efficient gradient-echo technique for functional MRI

A method providing improved slice efficiency for gradient-echo imaging requiring long echo times, such as in functional neuromagnetic resonance imaging, is presented. To enhance the volume coverage while maintaining the short imaging time of a conventional single-slice gradient-echo technique, an interleaved muttislice excitation is performed during the echo time. This technique allows detection of susceptibility changes, e.g., the acquisition of stimulated human cortical activation maps, on clinical MR instruments at multiple planes within total imaging times of a few seconds. The efficiency of the technique is demonstrated in the detection of temporary changes in T₂^* in functional MRI experiments of the human visual cortex at magnetic field strengths of 2 Tesla and 3 Tesla. Fourteen 128 × 128 slices can be acquired in 13 s to cover a large volume-of-interest in the same time that would be required for single-slice acquisition using the conventional technique.     

磁共振常规及其功能成像在原发性颅内淋巴瘤的应用价值

目的：探讨磁共振成像(MRI)、扩散加权成像(DWI)、磁共振灌注成像(PWI)、磁共振波谱成像(MRS)在原发性颅内淋巴瘤诊断及鉴别诊断中的应用价值。方法回顾性分析27例原发性颅内淋巴瘤患者的 MRI、DWI、PWI、MRS 影像资料。结果所有病灶 T1 WI 呈低-等信号,T2 WI 呈等、稍高、高信号,DWI 呈稍高、高信号。增强扫描22例病灶呈明显均匀强化,5例病灶呈不均匀强化。19例病灶可见“蝶翼征”“握拳征”“缺口征”“尖角征”。18例病灶均为低灌注表现。MRS 表现为病灶实质区 NAA 峰明显降低或消失,Cho 峰增高,23例出现高大 Lip 峰,12例出现 Lac 峰。结论磁共振常规及其功能成像在原发性颅内淋巴瘤的诊断及鉴别诊断中具有很高的应用价值,低灌注、肿瘤实质区出现高耸的 Lip 峰是原发性颅内淋巴瘤的特征性表现。     

Detection of brain activation using oxygenation sensitive functional spectroscopy

A nonwater-suppressed localized spectroscopy experiment using the PRESS-sequence has been used to study the signal changes of the water resonance during cortical activation. Significant effects with an effect-to-noise ratio up to 50:1 for a single shot experiment have been observed upon photic stimulation. The exceedingly high signal-to-noise ratio of the experiment was used to demonstrate signal changes as low as 0.1% after electrical stimulation of the median nerve.     

Alteration of blood oxygenation level-dependent signaling by local circulatory condition

PURPOSE: To determine regional differences in the relationship between neuronal activation and blood oxygenation level-dependent (BOLD) signal changes. MATERIALS AND METHODS: We performed BOLD and perfusion-based studies on healthy adult volunteers (40 for BOLD and 20 for perfusion-based studies) with visual stimulation of varied extent in the visual field of subjects. RESULTS: Regions with a significant negative correlation between the extent of visual stimuli and BOLD and perfusion responses were found bilaterally on the lateral surface of the occipital lobe just anterior to the occipital pole. These regions were located in the border zone between the territories of the middle and posterior cerebral arteries. CONCLUSION: Insufficient perfusion pressure in these regions may have led to attenuation of BOLD and perfusion responses to stimulation of a large portion of the visual field, or a condition in which a large extent of the visual areas was activated in the proximal regions of the territories perfused by the middle and posterior cerebral arteries. This finding supports the hypothesis that regional differences in circulatory condition can result in alterations of the relationship between neuronal activation and BOLD signal changes in the normal human brain.     

Role of functional imaging in the development and refinement of invasive neuromodulation for psychiatric disorders

Deep brain stimulation (DBS) is emerging as a powerful tool for the alleviation of targeted symptoms in treatment-resistant neuropsychiatric disorders. Despite the expanding use of neuropsychiatric DBS, the mechanisms responsible for its effects are only starting to be elucidated. Several modalities such as quantitative electroencephalography as well a intraoperative recordings have been utilized to attempt to understand the underpinnings of this new treatment modality, but functional imaging appears to offer several unique advantages. Functional imaging techniques like positron emission tomography, single photon emission computed tomography and functional magnetic resonance imaging have been used to examine the effects of focal DBS on activity in a distributed neural network. These investigations are critical for advancing the field of invasive neuromodulation in a safe and effective manner, particularly in terms of defining the neuroanatomical targets and refining the stimulation protocols. The purpose of this review is to summarize the current functional neuroimaging findings from neuropsychiatric DBS implantation for three disorders: treatment-resistant depression, obsessive-compulsive disorder, and Tourette syndrome. All of the major targets will be discussed (Nucleus accumbens, anterior limb of internal capsule, subcallosal cingulate, Subthalamic nucleus, Centromedial nucleus of the thalamus-Parafasicular complex, frontal pole, and dorsolateral prefrontal cortex). We will also address some apparent inconsistencies within this literature, and suggest potential future directions for this promising area.     

Imaging of human brain activity at 0.15 T using fluid attenuated inversion recovery (FLAIR) pulse sequences

A 34% change in signal intensity correlated with visual stimulation was observed in the occipital lobes of three normal volunteers examined with MRI at 0.15 T using fluid attenuated inversion recovery pulse sequences. Similar results were observed at 1.0 T. A double difference technique in which difference images are themselves opposed provided an increase in sensitivity.     

血氧水平依赖功能磁共振评价脑肿瘤恶性程度与脑皮层功能区距离和激活体积的相关性

目的 利用血氧水平依赖功能磁共振(BOLD-fMRI)评价脑肿瘤恶性程度与脑皮层功能区距离和激活体积的相关性.资料与方法 33例经手术病理证实的位于或邻近中央前回的脑肿瘤患者,包括恶性肿瘤组16例和良性肿瘤组17例,术前采用对指模式的组块(BLOCK)刺激方法,应用BOLD-fMRI成像技术,分析良恶性肿瘤与脑功能区边缘的距离及激活体积的相关性.结果 恶性肿瘤组BOLD激活体积为(31.29±10.87),良性肿瘤组BOLD激活体积为( 79.53±16.27),差异有统计学意义(P＜0.05);良性肿瘤组肿瘤边缘距脑皮层运动功能区距离平均(5.65±2.29) mm,恶性肿瘤组肿瘤边缘距脑皮层运动功能区距离平均(5.00±2.76) mm;恶性肿瘤组肿瘤至脑皮层功能区的距离与激活体积比呈正相关(R2=0.407,P＜0.01),良性肿瘤组肿瘤至脑皮层功能区的距离与激活体积比呈正相关(R2=0.25,P＜0.05),恶性肿瘤组较良性肿瘤组肿瘤至脑皮层功能区的距离与激活体积比的相关性更加显著.结论 脑肿瘤对周围脑组织产生影响,影响运动激活区状态,且在恶性肿瘤中更明显.     

基于弥散张量配准和皮层分割的白质纤维束追踪技术

目的 实现弥散张量图像与标准模板的非线性对齐,并以自动分割的皮层和皮层下区域为感兴趣区域进行纤维追踪.资料与方法 使用1.5T磁共振扫描仪,对1例脑梗死恢复期患者进行DTI、DWI和T1WI扫描,对DTI图像进行预处理,应用ART矫正DTI图像变形、使用dtitk将张量图像与标准模板进行非线性对齐,随后将对齐结果应用到T1WI中;应用FreeSurfer对标准化的T1WI进行皮层和皮层下脑区分割,在MedINRIA软件包中以分割后的脑区作为感兴趣区域,进行白质纤维追踪,经过在CINCH软件包中修剪后,在三维背景中显示白质纤维.结果 在标准脑空间中可清晰显示全脑表面、运动皮层、脑干以及锥体束.结论 利用张量图像配准和自动皮层分割技术,提供三维背景下较准确的白质纤维图像,可为临床诊断、判断预后提供依据.     

功能性磁共振成像在胶质瘤中的应用

综述功能性磁共振成像技术,皮层激发功能定位成像、灌注成像、磁共振波谱分析及扩散加权成像(包括扩散张量成像)对胶质瘤的临床应用价值。     

功能磁共振成像在脑膜瘤患者运动功能区的应用

目的：探讨血氧水平依赖功能磁共振技术(BOLD-fMRI)在脑膜瘤患者运动功能区术前定位的价值。方法收集10例经术后病理证实的靠近运动区的大脑凸面脑膜瘤患者,采用概率独立成分分析(PICA),进行 ICA 分析。术前术后行远期生活质量评估(KPS)生活状态评分来评价患者的状态。结果双侧主要运动皮层及辅助运动皮层均出现运动功能激活簇,其中患侧激活区与对侧激活区相比较为对称的有6例,出现明显推压移位的有4例,患者运动功能激活区均被肿瘤挤压导致功能区向前或向后移位,并且出现拉伸变形。结论 BOLD-fMRI 能够有效对脑肿瘤患者进行术前运动功能区定位,对脑膜瘤患者术前手术计划的制定能够提供帮助。     

Functional MRI of the kidneys

Renal function is characterized by different physiologic aspects, including perfusion, glomerular filtration, interstitial diffusion, and tissue oxygenation. Magnetic resonance imaging (MRI) shows great promise in assessing these renal tissue characteristics noninvasively. The last decade has witnessed a dramatic progress in MRI techniques for renal function assessment. This article briefly describes relevant renal anatomy and physiology, reviews the applications of functional MRI techniques for the diagnosis of renal diseases, and lists unresolved issues that will require future work. J. Magn. Reson. Imaging 2013;37:282–293. © 2012 Wiley Periodicals, Inc.     

聋人与正常人枕叶视皮层对亮度敏感性的功能磁共振成像研究

目的　利用血氧水平依赖性功能磁共振成像 (BOLD fMRI)技术 ,探讨聋人在固定频率、不同亮度的点光源刺激下 ,枕叶视皮层的兴奋情况 ,并比较兴奋区的分布、范围、强度与正常人是否一致。方法　对 12例聋人和 15例正常人给予闪烁频率为 8Hz、亮度为 0 7、2 2、5 0 0、180 0lm的点光源刺激 ,同时应用GE 1 5TSignaHorizonLX超导型磁共振成像系统 ,采集其脑部的BOLD fMRI数据。通过AFNI软件进行统计分析得到脑功能活动的图像。结果　在 4种不同亮度的点光源刺激下 ,聋人与正常人的枕叶视皮层均有明显兴奋区 ,且主要兴奋区位于枕叶矩状裂周围的视皮层内 ;随着亮度的增加 ,聋人与正常人视皮层兴奋区内的活动像素数 (numberofactivatedpixels)显著增加 (F正常人 =4 2 7,P <0 0 5 ;F聋人 =6 41,P <0 0 5 ) ,且在较高亮度刺激下 ,聋人枕叶视皮层的兴奋性高于正常人 ,但两者差异无显著性意义 (F =2 17,P >0 0 5 ) ;聋人与正常人视皮层内所有兴奋像素的平均活动水平(activationlevel)随亮度的增加变化不大 ,而在 4种亮度刺激下均兴奋的像素的平均活动水平却随着亮度的增加而有较明显的增加 ,但无显著性差异 (F正常人 =0 79,P >0 0 5 ;F聋人 =1 6 ,P >0 0 5 )。结论聋人与正常人对亮度的基本反应特性是相     

Functional Neuroanatomy in Depressed Patients with Sexual Dysfunction: Blood Oxygenation Level Dependent Functional MR Imaging

Objective

To demonstrate the functional neuroanatomy associated with sexual arousal visually evoked in depressed males who have underlying sexual dysfunction using Blood Oxygenation Level Dependent-based fMRI.

Materials and Methods

Ten healthy volunteers (age range 21-55: mean 32.5 years), and 10 depressed subjects (age range 23-51: mean 34.4 years, mean Beck Depression Inventory score of 39.6±5.9, mean Hamilton Rating Scale Depression (HAMD)-17 score of 33.5±6.0) with sexual arousal dysfunction viewed erotic and neutral video films during functional magnetic resonance imaging (fMRI) with 1.5 T MR scanner (GE Signa Horizon). The fMRI data were obtained from 7 oblique planes using gradient-echo EPI (flip angle/TR/TE=90°/6000 ms/50 ms). The visual stimulation paradigm began with 60 sec of black screen, 150 sec of neutral stimulation with a documentary video film, 30 sec of black screen, 150 sec of sexual stimulation with an erotic video film followed by 30 sec of black screen. The brain activation maps and their quantification were analyzed by SPM99 program.

Results

There was a significant difference of brain activation between two groups during visual sexual stimulation. In depressed subjects, the level of activation during the visually evoked sexual arousal was significantly less than that of healthy volunteers, especially in the cerebrocortical areas of the hypothalamus, thalamus, caudate nucleus, and inferior and superior temporal gyri. On the other hand, the cerebral activation patterns during the neutral condition in both groups showed no significant differences (p < 0.01).

Conclusion

This study is the first demonstration of the functional neuroanatomy of the brain associated with sexual dysfunction in depressed patients using fMRI. In order to validate our physiological neuroscience results, further studies that would include patients with other disorders and sexual dysfunction, and depressed patients without sexual dysfunction and their treatment response are needed.