3.0T磁共振脑功能成像对额顶叶肿瘤神经微创手术的应用价值

目的探讨3.0T磁共振脑功能成像(fMRI)在额顶叶肿瘤神经微创手术前的应用价值。方法在3.0T磁共振上,49例额顶叶肿瘤病例术前行颅脑常规MRI平扫加增强和fMRI检查。依据fMRI成像后处理脑功能活动定位图(functional brain mapping,FBM)及常规MR扫描图像制定合理的手术计划,找出额顶叶肿瘤神经微创手术最佳路径切除肿瘤。结果 49例FBM图清晰的显示了大脑皮层左右两侧运动功能区的位置、大小和移位情况,为确定手术路径提供重要的参考依据。49例微创手术也取得比较满意的效果。结论 3.0TfMRI对额顶叶肿瘤神经微创手术的术前评价有重要临床意义,对手术切除脑功能区周围肿瘤并保留运动功能有重要的指导作用。     

灰质异位脑功能连接的功能磁共振成像研究

目的通过观察灰质异位脑功能连接区的空间分布形式,探索灰质异位与正常脑区间的神经功能联系。方法研究对象为8例确诊为双侧灰质异位癫痫患者,经Siemens 3.0 T磁共振仪采集静息态及3D结构像数据。以异位灰质团块作为种子点,进行基于相关的全脑功能连接分析,并对异位灰质功能连接网络存在的模式进行观察分析。结果 (1)一侧异位灰质与对侧异位灰质存在正相关功能连接;(2)异位灰质与双侧基底神经节存在正相关连接。(3)异位灰质与正常大脑皮层存在正相关功能连接,但其空间模式与异位灰质所处的部位有关。(4)异位灰质与双侧大脑皮层也存在负相关功能连接区域,但其空间模式无明显一致性。结论灰质异位不是孤立的异常脑结构,其不但与对侧的异位灰质保持功能连接,还与众多大脑皮层区保持着广泛的功能连接,这可能由于异位灰质团与正常皮层具有相同起源以及相似发育过程而形成的。其与基底神经节存在功能连接可能是异位灰质经常引发癫痫发作的病理生理基础之一。     

Exploring Functional Connectivity of Gray Matter Heterotopia Using fMRI

目的 通过观察灰质异位脑功能连接区的空间分布形式,探索灰质异位与正常脑区间的神经功能联系.方法 研究对象为8例确诊为双侧灰质异位癫痫患者,经Siemens 3.0 T磁共振仪采集静息态及3D结构像数据.以异位灰质团块作为种子点,进行基于相关的全脑功能连接分析,并对异位灰质功能连接网络存在的模式进行观察分析.结果 (1)一侧异位灰质与对侧异位灰质存在正相关功能连接;(2)异位灰质与双侧基底神经节存在正相关连接.(3)异位灰质与正常大脑皮层存在正相关功能连接,但其空间模式与异位灰质所处的部位有关.(4)异位灰质与双侧大脑皮层也存在负相关功能连接区域,但其空间模式无明显一致性.结论 灰质异位不是孤立的异常脑结构,其不但与对侧的异位灰质保持功能连接,还与众多大脑皮层区保持着广泛的功能连接,这可能由于异位灰质团与正常皮层具有相同起源以及相似发育过程而形成的.其与基底神经节存在功能连接可能是异位灰质经常引发癫痫发作的病理生理基础之一.     

磁共振脑灰白质成像在脑灰质异位症中的临床应用

目的：探讨磁共振脑灰白质成像在脑灰质异位症中的诊断价值。方法：回顾性分析5例经临床及MRI检查确诊的脑灰质异位症患者，全部患者均行脑MRI常规T1WI、T2WI序列、FLAIR序列和脑灰白质成像检查。结果：5例脑灰质异位症患者在MRI各扫描序列上病灶信号与脑灰质信号完全相同，特别是在脑灰白质成像上对异位的灰质灶观察更为满意，更有利于判断病变的性质。结论：脑灰白质成像在观察灰质异位方面有独到价值，在分析癫痫病因方面可提供更直接的影像学信息。对于脑灰质异位症患者，脑灰白质成像对于帮助发现病灶并判断其性质甚为必要，是对常规序列的必要补充，具有较高的临床应用价值。     

磁共振脑功能成像研究进展

血液动力学反应与神经活动间存在着密切的联系,磁共振脑功能成像是利用大脑功能区活动时,脑组织的活跃可引起局部顺磁性的脱氧血红蛋白生成减少,使局部脑组织Ｔ２及Ｔ２的弛瞎长,从而获得激活脑区的功能成像图,其突出特点是应用了平面回波（ＥＰＩ）技术,磁共振脑功能成像已用于人脑各种功能活动的研究,通过对颅内占位性病变对邻近重要功能区造成影响的研究,能够进一步指导神经外科医师合理地制定手术计划,对改善手术预后有     

臂丛损伤健侧C7神经移位术后大脑运动皮质远期功能重组

目的:运用功能磁共振成像方法研究臂丛根性撕脱伤并行健侧C7神经移位术后大脑运动功能的远期变化。方法:8例经临床检查和手术证实一侧全臂丛根性撕脱伤男性患者(健侧C7术后两年以上)以及9名健康男性被试接受磁共振扫描。运动任务为单侧手的抓握运动。结果:健康对照组单侧手运动时所有被试均主要激活对侧初级运动区和辅助运动区而且偏侧化系数均大于0。组分析结果同样显示单侧手运动主要激活对侧大脑半球运动脑区。患者患肢运动激活双侧运动皮质,但偏侧化系数大于0,提示患肢运动主要激活对侧运动皮质(M1和SMA)。5例右侧臂丛损伤患者组分析结果显示患肢运动主要激活对侧运动皮质。3例左侧臂丛损伤患者单个被试偏侧化系数分析及激活图像显示患肢运动主要激活脑区位于对侧运动皮质。结论:健侧C7神经移位术后,大脑会试图利用原躯体运动区对患肢运动进行控制。     

MR双反转恢复成像在灰质异位诊断中的初步应用

目的 初步探讨MR双反转恢复(DIR)序列在灰质异位诊断中的价值.资料与方法 回顾性分析本院9例灰质异位症患者的影像学资料,重点观察灰质异位病灶在DIR上的表现.结果 根据病灶形态和位置分型:皮层下灰质异位(SCH)5例、室管膜下灰质异位(PNH)2例、皮层下带状灰质异位(SBH)2例;在DIR上,脑内灰质结构表现为高信号,白质结构表现为低信号,灰质异位病灶均表现为边界清楚、形状不规则的高信号,与脑皮层和灰质核团的信号相一致.结论 DIR序列能够选择性抑制脑脊液和白质的信号,突出显示灰质结构,灰白质对比度高,对灰质异位的诊断具有显著价值.     

磁共振扩散成像评价阻塞性睡眠呼吸暂停低通气综合征患者认知功能损害的研究进展

阻塞性睡眠呼吸暂停低通气综合征是一种以夜间睡眠反复缺氧及睡眠碎片化为特征的睡眠障碍疾病,可引起广泛的大脑结构及功能改变,导致神经认知功能受损。磁共振扩散成像是基于无创检查活体内水分子的扩散运动反映组织微结构的变化,可以从分子水平早期观察患者脑组织微观结构的改变,分析其与认知功能改变的关系,并监测持续气道正压通气治疗效果。本文对磁共振扩散成像评价阻塞性睡眠呼吸暂停低通气综合征患者认知功能的研究进展进行综述。     

类风湿关节炎病人颈脊柱的动态和静态磁共振检查的比较

目的:比较动态和静态磁共振检查对类风湿关节炎侵犯颈段脊柱的诊断价值。材料和方法:对5例正常志愿者和20例类内湿关节炎病人进行了颈段脊柱动态磁共振功能成像,使用一个体位支架,使病人在动态检查时可以作颈部连续前、后曲运动。结果:动态磁共振成像可较好地辨别齿状突上、前、后关节囊组织的分布,特别是评价在曲屈和伸展运动时脊髓的压迫和侵犯。特别适合于评价寰枕和寰枢平面的脊柱稳定性。磁共振电影与常规摄片、ＣＴ以及静态磁共振检查比较,对扁颅底和颈段脊髓的显示更为清楚。结论:动态磁共振成像是类风湿关节炎颈部病变的重要检查方…     

SonoWand超声神经导航系统在脑肿瘤手术中的应用

目的 评价术中三维超声神经导航系统在脑肿瘤手术中的应用价值.方法 应用SonoWand超声神经外科系统,对术前计算机体层摄影术/磁共振成像资料进行手术计划和术中导航,也可在术中直接应用三维超声进行导航.结果 本组进行脑肿瘤手术13例,共14个病灶;全切除13个(92.9%),次全切除1个(7.1%);手术切口和骨瓣较常规开颅手术小;病灶邻近运动区的7例患者,5例术后肌力未受影响,2例出现一过性肌力下降,2周后恢复至术前水平.本组无症状恶化及死亡者,未发现应用超声神经导航系统导致的手术并发症.结论 SonoWand超声神经导航系统具有定位准确、微侵袭、安全可靠等特点,通过术中实时超声扫描,解决了脑组织移位问题,有助于提高脑肿瘤的全切除率.     

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。     

Optimized activation of the primary sensorimotor cortex for clinical functional MR imaging

BACKGROUND AND PURPOSE: One application of functional MR imaging is to identify the primary sensorimotor cortex (M1 and S1) around the central sulcus before brain surgery. However, it has been shown that undesirable coactivation of nonprimary motor areas, such as the supplementary motor area and the premotor area, can interfere with the identification of the primary motor cortex, especially in patients with distorted anatomic landmarks. We therefore sought to design a simple functional MR imaging paradigm for selective activation of the primary sensorimotor cortex. METHODS: Different paradigms using finger tapping for motor activation were examined and compared with respect to the distribution of activated voxels in primary and nonprimary cortical areas. Studies were conducted in 14 healthy volunteers using a blood oxygen level-dependent multislice echo-planar imaging sequence. RESULTS: The most selective activation of the primary sensorimotor cortex was obtained with a paradigm combining right-sided finger tapping as the activation condition with left-sided finger tapping as the control condition. Analysis of the signal time course of primary and nonprimary areas revealed that the highly selective primary motor activation was due to it being restricted to contralateral finger movements, as opposed to the nonprimary motor areas, which were activated by ipsilateral, contralateral, and bilateral finger movements alike. CONCLUSION: When performing functional MR imaging to determine the location of the primary sensorimotor cortex, one should compare unilateral voluntary movements as the activation condition with contralateral movements as the control condition to accentuate activation of the primary motor area and to suppress undesirable coactivation of nonprimary motor areas.     

The effect of prior surgery on blood oxygen level-dependent functional MR imaging in the preoperative assessment of brain tumors

BACKGROUND AND PURPOSE: Blood oxygen level-dependent functional MR imaging (BOLD fMRI) is a clinically useful technique for preoperative mapping of eloquent cortices in patients with brain tumors. The purpose of this study was to determine the effect on BOLD fMRI accuracy of susceptibility artifacts caused by prior surgery by comparing volumes of activation in the primary motor cortex (PMC) of patients with and without prior brain surgery. METHODS: The volumes of fMRI activation of the PMC were measured for the tumor and nontumor sides in patients with (n = 13) and without (n = 30) prior neurosurgery. Statistical comparisons of the volumes were performed by using paired t tests and linear regression analysis. The location and degree of susceptibility artifact were subjectively assessed. RESULTS: No significant difference was found between the mean tumor and nontumor volumes of fMRI activations in patients without prior surgery (P = .51). In patients who had prior surgery, the volume of activation was significantly smaller on the side of the prior operation when compared with the contralateral side (P = .001). The volume of activation on the side of the tumor was also significantly smaller in the patients with prior surgery compared with those without prior surgery (P < .001). Nevertheless, the PMC was identified in all cases, and its location was confirmed intraoperatively. CONCLUSION: Prior surgery is associated with a decrease in the volume of fMRI activation in patients with prior surgery; however, by examining the T2 images, an astute radiologist can recognize this phenomenon, draw the appropriate conclusions, and correctly identify the PMC.     

肌萎缩侧索硬化症患者大脑运动皮层的功能MRI研究

目的 研究肌萎缩侧索硬化症(ALS)患者顺次对指运动时脑部运动皮层的血氧水平依赖(BOLD)功能MRI(fMRI)变化.方法 对15例临床确诊及拟诊为ALS的患者(ALS组)和15名年龄、性别相匹配的健康志愿者(对照组)进行BOLD MR扫描.所有受试者均为右利手,无其他疾病,近期未服用过影响神经系统功能的药物,受试者进行频率为1～2次/s的顺次对指运动.使用3.0 T MR机获取梯度回波-回波平面成像(GRE-EPI)序列功能图像.所得数据采用统计参数图(SPM)2软件进行分析.激活脑区体积的比较采用t检验.结果 2组在完成相同运动任务时均有激活的脑区包括:双侧主感觉运动皮层(PSM)、双侧运动前区(PA)后部、双侧辅助运动区(SMA)、对侧外下运动前区(ILPA)、双侧顶叶区(PAR)和同侧小脑半球.ALS组激活体积较对照组激活体积明显增大的区域包括:双侧PSM及双侧PA后部[右手同侧激活:ALS组为(924.5±141.1)mm3,对照组为(829.9±98.4)mm3(P=0.05);右手对侧激活:ALS组为(9143.8±702.8)mm3,对照组为(8638.8±506.4)mm3(P＜0.05);左手同侧激活:ALS组为(1162.5±357.4)mm3,对照组为(902.5±184.2)mm3(P＜0.05);左手对侧激活:ALS组为(8255.2±870.2)mm3,对照组为(5934.6±616.4)mm3(P＜0.05)]、双侧SMA[右手双侧激活:ALS组为(6564.3±720.6)mm3,对照组为(4710.7±416.3)mm3(P＜0.05);左手双侧激活:ALS组为(6970.5±961.8)mm3,对照组为(3688.9±672.3)mm3(P＜0.05)]及同侧小脑半球[右手同侧激活:ALS组为(2720.0±1154.2)mm3,对照组为(254.3±84.4)mm3(P＜0.05);左手同侧激活:ALS组为(4794.4±1237.0)mm3,对照组为(1689.0±719.6)mm3(P＜0.05)].ALS组额外激活的区域包括:同侧ILPA、对侧小脑半球及双侧内囊后肢.结论 ALS组与对照组完成相同运动模式所激活的脑区相似,但ALS组激活的区域有所增加.ALS患者激活增大的脑区可能为功能重组,额外激活的脑区则可能为功能代偿.     

简单与复杂手指运动的fMRI对比分析

目的；研究简单和复杂手指运动激活脑皮层功能区的异同。资料与方法：选择一组正常志愿者（12例）按要求分别进行简单与复杂手指运动，同时进行BOLD功能性磁共振成像（fMRI)扫描，用t检验统计学方法分析获得运动状态与静息状态信号对比的脑功能图。对比观察脑皮层区的兴奋区的异同。结果：12例受试者中，复杂手指运动可激活对侧初级躯体感觉区（SM1),11例可观察到一侧或双侧辅助运动区（SMA）兴奋，9例运动前区（PMA）兴奋；简单手指运动则均表面为对侧SM1兴奋，而MA，PMA区被激活仅为2例和5例。激活区检测的可靠复性大于95％。结论：复杂手指运动需要更多的脑皮层功能区参与运动的协调，因而能更多地激活非初始运动皮层区。     

Functional MRI activation of somatosensory and motor cortices in a hand-grafted patient with early clinical sensorimotor recovery

The aim of this study was to investigate somatosensory and motor cortical activity with functional MRI (fMRI) in a hand-grafted patient with early clinical recovery. The patient had motor fMRI examinations before transplantation, and motor and passive tactile stimulations after surgery. His normal hand and a normal group were studied for comparison. A patient with complete brachial plexus palsy was studied to assess the lack of a fMRI signal in somatosensory areas in the case of total axonal disconnection. Stimulating the grafted hand revealed significant activation in the contralateral somatosensory cortical areas in all fMRI examinations. The activation was seen as early as 10 days after surgery; this effect cannot be explained by the known physiological mechanisms of nerve regeneration. Although an imagination effect cannot be excluded, the objective clinical recovery of sensory function led us to formulate the hypothesis that a connection to the somatosensory cortex was rapidly established. Additional cases and fundamental studies are needed to assess this hypothesis, but several observations were compatible with this explanation. Before surgery, imaginary motion of the amputated hand produced less intense responses than executed movements of the intact hand, whereas the normal activation pattern for right-handed subjects was found after surgery, in agreement with the good clinical motor recovery.     

健康成人及脑肿瘤患者利手和非利手简单与复杂运动fMRI研究

目的:应用脑血氧水平依赖性功能MRI(BOLD-f MRI)研究健康成年人及脑肿瘤患者运动功能皮层定位并探讨其对脑肿瘤的临床应用价值。方法:10例健康志愿者和32例脑肿瘤患者(术前25例,术后7例)共42例受试者,行利手、非利手的单手握拳(简单运动)或单手对指(复杂运动)运动的脑BOLD-f MRI检查,分析脑肿瘤对运动皮层位置和功能的影响。结果:健康成人运动皮层主要位于对侧躯体感觉运动皮层(SMC),单或双侧辅助运动区(SMA)、运动前区(PMA)和双侧小脑半球。复杂运动或非利手运动时脑功能激活区范围和程度较简单运动或利手运动时增多。累及功能皮层的脑肿瘤患者,可见患侧部分脑功能区激活,但激活区移位、分布弥散。术后脑肿瘤患者功能皮层的位置基本恢复正常。结论:BOLD-f MRI是一种有效而无创的脑功能皮层定位方法,有利于脑肿瘤的精确定位诊断并指导临床治疗。     

On the application of susceptibility-weighted ultra-fast low-angle RARE experiments in functional MR imaging.

The applicability of displaced, split-echo, and phase-cycled variants of the blood oxygenation level-dependent (BOLD) sensitized ultra-fast low-angle rapid acquisition and relaxation enhancement (UFLARE) technique for the mapping of brain function are examined in functional magnetic resonance imaging (fMRI) experiments at high magnetic field strength (3 T). Activation maps are presented for visual and motor-sensory activation. For the visual studies the range of the stimulation-associated signal intensity changes is 5-7% in voxels containing mainly gray matter and 10-15% in voxels dominated by larger vessels. The motor studies reveal signal changes of 5-10% in the primary motor cortex and in the supplementary motor area. For gray matter, T2* increases from 31.2 +/- 1.5 msec under baseline conditions to 33.0 +/- 1.5 msec during periods of visual stimulation. The results clearly demonstrate that T2*-weighted UFLARE is a robust and reliable method for detection of brain activation. The relative pros and cons of displaced, split-echo, and phase-cycled T2*-sensitized UFLARE versions are discussed for fMRI applications. Since the susceptibility weighting can be freely adjusted from zero upward, the UFLARE variants used are particularly suitable for functional examinations in regions with poor magnetic field homogeneity and at high magnetic field strengths.     

Whole-brain functional MR imaging activation from a finger-tapping task examined with independent component analysis

BACKGROUND AND PURPOSE: Independent component analysis (ICA), unlike other methods for processing functional MR (fMR) imaging data, requires no a priori assumptions about the hemodynamic response to the task. The purpose of this study was to analyze the temporal characteristics and the spatial mapping of the independent components identified by ICA when the subject performs a finger-tapping task. METHODS: Ten healthy subjects performed variations of the finger-tapping task conventionally used to map the sensorimotor cortex. The scan data were processed with ICA, and the temporal configuration of the components and their spatial localizations were studied. The locations with activation were tabulated and compared with locations known to be involved in the organization of motor functions in the brain. RESULTS: Components were identified that correlated to varying degrees with the conventional boxcar reference function. One or more of these components mapped to the sensorimotor cortex, supplementary motor area (SMA), putamen, and thalamus. By means of ICA components, sensorimotor cortex, supplementary motor area, and superior cerebellar activation were identified bilaterally in 100% of the subjects; thalamus activation was contralateral to the active hand in 80%; and putamen activation was contralateral to the active hand in 60%. CONCLUSION: ICA processing of multislice fMR imaging data acquired during finger tapping identifies the sensorimotor cortex, SMA, cerebellar, putamen, and thalamic activation. ICA appears to be a method that provides information on both the temporal and spatial characteristics of activation. Multiple task-related components can be identified by ICA, and specific activation maps can be derived from each separate component.     

Functional MRI for immediate monitoring stereotactic thalamotomy in a patient with essential tremor

The effect of stereotactic thalamotomy was assessed with pre- and postoperative functional magnetic resonance imaging (fMRI) under motor stimulation. A patient with unilateral essential tremor (ET) of the left arm underwent stereotactically guided thalamotomy of the right ventral intermediate thalamic nucleus (VIM). FMRI was done directly before and after surgery on a 1.5-Tesla scanner. The stimulation paradigm was maintainance of the affected arm in an extended position and hand clenching being performed in a block design manner. Statistical analysis was done with Brain Voyager 2000. After thalamotomy the tremor diminished completely. As a difference between the pre- and postoperative fMRI, a significant activation was found in the VIM contralateral to the activation site, adjacent to the inferior olivary nucleus contralateral to the activation site and in the dorsal cingulum. In conclusion, fMRI can detect the functional effect of thalamotomy for tremor treatment. Direct postoperative fMRI provides a sufficient method for estimating the effect of thalamotomy immediately after intervention. The importance of the intermediate thalamic nucleus and the olivary nucleus in tremor generation is supported by our findings.