运动双手食指后应用磁源性影像对运动皮质及体感皮质定位

目的 确定运动双手食指后应用磁源性影像对运动皮质及体感皮质功能区定位的价值并探讨其成像方法。方法 6例受试者接受左、右侧视觉光刺激后运动相应侧食指，双手食指下方各放置一块垫板，垫扳上有一个光电偶合器，食指抬起后数据采集计算机即可将光电偶合的一刻为“零”对脑反应信号进行叠加。应用脑磁图记录运动及体感反应叠加后的脑电磁波并将其与相应受试者头MRI叠加形成磁源性影像。结果 食指运动后，每个受试者双侧半球均出现一个最高的波峰，左右半球潜伏期分别为(41．5&;#177;7．8)ms和(35．5&;#177;3．6)ms。受试者之间左、右半球皮质兴奋的潜伏期(WI)差异无显著意义(t＝2．046，P＝0．096)。将其CCD叠加到MRI上可见ECD均位于中央后回。每个受试者在最高波峰之前出现一个小的波峰，潜伏期为负值，左、右半球分别为-(52．9&;#177;25．9)ms和—(63．8&;#177;19．5)ms。受试者之间左、右半球皮质兴奋的潜伏期(W2)差异无显著意义(t＝1．342，P=0．237)。由磁源性影像显示兴奋的皮质位于中央前回。结论 磁源性影像可很好地显示健康受试者运动皮质及体感皮质，可对运动皮质及体感皮质进行精确定位。     

磁源成像对中、英文语言功能区的研究

目的：探索通过中、英文单词刺激健康志愿者后用磁源成像（MSI）无创性测定语言功能区的位置。方法：作者使用脑磁图对8例右利健康志愿者进行语言接受功能区的功能成像，在此过程中，受试者进行分别听150对中、英文单词的文字识别任务。结果：MSI显示8例受试者中有7例左侧半球内的兴奋明显强于右侧半球，有1例双侧大脑半球内的兴奋大致相等；中、英文单词刺激的磁反应波峰的后期兴奋（刺激后300-600ms）的磁源均位于颞上回和颞中回的后部。结论：MSI是一项有发展前途的、无创伤性的检查方法，它不但可以判断语言优势半球，而且可以判定语言功能区的位置。     

脑磁图SAM分析法定位皮质运动功能初步探讨

目的利用脑磁图SAM分析法研究健康受试者运动皮质反应及其磁源影像定位价值。方法10例右利手健康受试者给予tone音刺激,受试者听到声音后右手食指触压按键感应器。以运动触发为基点进行平均,选择触发点前后的波形分别用等价电流偶极子(ECD)和合成孔径磁场测量(SAM)进行分析,最终形成三维的脑功能影像图。结果所有10例受试SAM法均定位大脑皮层中央前回,与运动皮层解剖位置一致,ECD法7例定位于中央前回运动中枢,3例定位偏差。结论脑磁图SAM分析方法可以很好地显示皮质运动反应并能对皮层运动功能进行成功定位。     

磁源性影像对颅内肿瘤患者初级体感皮质定位的研究

目的:确定磁源性影像(MSI)对颅内肿瘤性病变患者脑初级体感皮质定位的价值。材料与方法:6例颅内肿瘤接近体感皮质的患者,其中男4例,女2例,年龄15~68岁,平均46岁。对患者双侧腕部正中神经进行电刺激。用306通道全头型生物磁仪(MEG)进行脑磁场测量。MRI设备使用GE公司生产的1.5T Signa Horizon成像系统。结果:所有受试者均出现M20波峰(电刺激腕部正中神经后20ms左右出现的体感诱发磁场)及M35波峰(电刺激腕部正中神经后35ms左右出现的体感诱发磁场),M20波峰潜伏期为21.2±0.9ms。MRI显示病变侧脑沟明显变窄。MSI明确地显示出脑体感皮质与肿瘤的立体关系,借此外科医师很容易地识别出中央沟的位置。结论:MSI对帮助术前制定的手术计划、术中的程序以及提供肿瘤与脑功能区的立体关系有重要意义。     

颞叶躯体感觉中枢——脑磁源成像研究

目的利用脑磁源成像观察正常人在躯体感觉刺激时中枢的兴奋情况。方法研究包括10名正常志愿者。通过专用电刺激仪刺激手部皮肤,固定电流脉冲0.3ms,刺激间期0.5s,叠加1000次。用等电流偶极描述局灶性皮质活动,受试者的头部空间形态用球形模型化。结果体感刺激明显激活位于对侧中央前、后回的第一躯体感觉皮层和颞上回。颞叶ECD的潜伏期比第一躯体感觉中枢的长,ECD的强度较低。结论体感刺激激活对侧第一躯体感觉皮层,颞叶参与处理体感刺激。     

脑磁图与视频脑电图定位癫痫灶的结果比较

背景: 多数癫痫患者的癫痫发作经药物治疗可得到控制,但对于难治性癫痫患者来说,手术可能是一种治疗选择,正确定位癫痫患者的致痫灶是癫痫手术成功的基础.癫痫患者的术前评估包括视频脑电图、MRI、正电子发射计算机体层摄影/单光子发射计算机体层摄影和神经心理测试等.脑磁图作为一种新的无创性术前检测技术,已被许多国家用于癫痫外科手术计划和大脑功能的研究.目的:术前采用磁源成像技术进行对手术治疗的难治性癫痫患者进行致痫灶定位,并与无创性视频脑电图对比,参考手术效果,评估其定位价值.设计、时间及地点:回顾性病例分析,于2001-11/2005-12在广东三九脑科医院脑磁图室完成.对象:选择进行脑磁图检查618例的癫痫患者,采集其自发磁场信号进行单偶极子定位分析诊断.对其中149例MRI检查有结构改变、病史在2年以上者进行了手术治疗,病程2～35年,平均9.5年.方法:用148通道全头型脑磁系统(Magnes WH2500, 4-D Neuroimaging, San Diego, CA, USA)在磁屏蔽室采集脑自发磁场,采样频率为508.63 Hz,带通为1.0～100 Hz,采集30 min发作间歇期的自发脑磁,采用单个等效电流偶极子进行数据分析.分析结果最后重叠在MRI-T1加权像上,形成磁源成像.主要观察指标:术前视频脑电图、MRI和脑磁图结果及术后随访结果.结果:30 min发作间期的脑磁图检测到明显的癫痫样活动的敏感度为91%,并且大部分患者,其等效偶极子主要分布于结构性异常的边缘和邻近区域.与无创性视频脑电图(38.9%,58/149)相比,利用脑磁图可以对大部分MRI上有病变的患者(62.4%,93/149)进行精确定位并且能够确定切除区域.对资料完整的89 例患者进行了3～35个月的随访,平均随访9个月.89例患者中有72例(80.9%)术后未出现癫痫发作(EngelⅠ);7例(7.9%)癫痫发作极少或癫痫发作频率减少90%以上(Engel Ⅱ和 Engel Ⅲ);10例(11.2%)癫痫发作频率无明显减少(Engel Ⅳ和Engel Ⅴ),总有效率达88.8%(EngelⅠ～Ⅲ).结论:与无创性视频脑电图相比,利用脑磁图可以对大部分MRI上出现结构性病变的癫痫患者致痫灶进行精确定位,并且能够确定切除区域.     

运动双手食指后应用磁源性影像对运动皮质及体感皮质定位

目的确定运动双手食指后应用磁源性影像对运动皮质及体感皮质功能区定位的价值并探讨其成像方法。方法6例受试者接受左、右侧视觉光刺激后运动相应侧食指,双手食指下方各放置一块垫板,垫板上有一个光电偶合器,食指抬起后数据采集计算机即可将光电偶合的一刻为“零”对脑反应信号进行叠加。应用脑磁图记录运动及体感反应叠加后的脑电磁波并将其与相应受试者头MRI叠加形成磁源性影像。结果食指运动后,每个受试者双侧半球均出现一个最高的波峰,左右半球潜伏期分别为(41.5±7.8)ms和(35.5±3.6)ms。受试者之间左、右半球皮质兴奋的潜伏期(W1)差异无显著意义(t=2.046,P=0.096)。将其ECD叠加到MRI上可见ECD均位于中央后回。每个受试者在最高波峰之前出现一个小的波峰,潜伏期为负值,左、右半球分别为-(52.9±25.9)ms和-(63.8±19.5)ms。受试者之间左、右半球皮质兴奋的潜伏期(W2)差异无显著意义(t=1.342,P=0.237)。由磁源性影像显示兴奋的皮质位于中央前回。结论磁源性影像可很好地显示健康受试者运动皮质及体感皮质,可对运动皮质及体感皮质进行精确定位。     

直接皮质电刺激在脑功能区手术中对脑功能的保护作用

目的：探讨脑重要功能区手术中应用直接皮质电刺激联合皮质体感诱发电位定位脑功能区的方法及意义。方法：16例脑重要功能区病变的患者在唤醒麻醉下进行显微外科手术，利用皮质诱发电位及皮质直接电刺激定位感觉区、运动区及语言区，在保护脑功能区功能不受损的前提下，最大限度的手术切除病变。结果：12例位于运动感觉区的患者利用体感诱发电位及皮质电刺激确定出运动感觉区，其中6例利用体感诱发电位总位相倒置确定出中央沟，记录到明显的P20-N25倒置波形，波幅最大及波形分化最佳，经直接皮质电刺激确认为运动区。4例病变位于左侧额颞叶的患者通过皮质直接电刺激确定出语言区。术后无一例出现长期的功能障碍加重，并且术后功能均较术前明显好转。皮质电刺激未出现特殊并发症。结论：术中体感诱发电位及直接皮质电刺激可准确实时确定脑功能区，可最大限度的保护患者功能，最大限度的切除病变。     

磁敏感加权成像对脑肿瘤诊断价值初探

目的探讨磁敏感加权成像（SWI）对脑肿瘤的诊断价值。方法41例脑肿瘤患者行常规横断位（T1WI、T2WI）和横断位SWI检查,其中30例同时行横断位T1WI和SWI增强扫描。观察SWI图像上肿瘤显示、瘤周水肿、肿瘤出血、肿瘤钙化及肿瘤静脉等5个项目,并对所有项目进行评分（0～3）,采用析因设计的方差分析及LSD多重检验。结果SWI图像上,脑膜瘤、低级别星形细胞瘤表现为等或稍高信号;复发性脑膜瘤、多数高级别星形细胞瘤及脑转移瘤实性成分表现为稍低信号。脑膜瘤内部新生血管较少,周围静脉呈弧形受压改变;低级别星形细胞瘤肿瘤静脉稀疏、散在分布;复发性脑膜瘤、高级别星形细胞瘤及转移瘤内部静脉血管丰富,瘤周静脉表现各异。相位图上肿瘤钙化以低信号为主,而且钙化灶最外层表现为高信号;出血灶信号与之相反。瘤周水肿表现为高信号。在肿瘤出血、肿瘤钙化及肿瘤静脉显示方面,SWI与T1WI、T2WI评分结果差别具有统计学差异（P〈0．01）;在瘤周水肿显示方面,SWI与T2WI评分结果差别无统计学意义;在肿瘤显示方面,CE-SWI及CE-T1WI与其他序列评分结果的差别有统计学意义（P〈0．01）。结论SWI在显示肿瘤的一般影像特征的基础上突出显示肿瘤静脉、出血代谢物和钙化灶,提供不同于常规MRI序列的肿瘤内部病理信息,相位图像有助于肿瘤出血与钙化的鉴别。     

老年人大脑听觉皮质功能区老化的神经磁学研究

目的：分析老年人随年龄增加出现的大脑听觉皮质老化的发生发展规律，为老年聋的防治提供依据。 方法：所有受试者为2002-01／2005-01在河北省人民医院耳鼻咽喉科门诊就诊者。以306通道全头型脑磁图仪分别测试青年组（18～28岁）30例、老年前期组（45-59岁）35名、老年期组（60-80岁）32名健康受试者0．5，1，2，4，6kHz纯音诱发的双侧大脑半球听觉皮质脑磁场M100，并与其MRI解剖影像信息叠加整合，得到大脑听觉皮质磁源性影像。分析比较不同年龄组各刺激频率纯音所诱发M100的潜伏期、波幅及其等电流偶极在X、Y，Z坐标轴的三维定位。 结果：97名健康人均完成全部测试，进入结果分析。①老年前期组和老年期组与青年对照组比较，其纯音听力在所有测试频率均随年龄增加显著逐渐下降（P〈0．01）；M100的潜伏期随年龄增加逐渐延长．波幅逐渐降低。②老年期组在各刺激声频率诱发的M100潜伏期和波幅均较老年前期组和青年组出现了有统计学意义的显著延长或降低；M100的等电流偶极位置双侧大脑半球听觉皮质均在2，6kHz刺激声发生向内、后、下方向的位移或偏离，在4kHz均发生向内、后、上的位移或偏离；等电流偶极的位置分布亦随年龄增加而逐渐分散。 结论：老年人的大脑听觉皮质随年龄增加而发生的老化主要表现为大脑听觉皮质在激活的时间、程度和空间位置的重组，探寻纠正和改善这种重组发生的方法可能成为未来有希望预防和治疗老年人年龄相关性听力下降发生和发展的一种有效途径。     

High fidelity tonotopic mapping using swept source functional magnetic resonance imaging

Tonotopy, the topographic encoding of sound frequency, is the fundamental property of the auditory system. Invasive techniques lack the spatial coverage or frequency resolution to rigorously investigate tonotopy. Conventional auditory fMRI is corrupted by significant image distortion, sporadic acoustic noise and inadequate frequency resolution. We developed an efficient and high fidelity auditory fMRI method that integrates continuous frequency sweeping stimulus, distortion free MRI sequence with stable scanner noise and Fourier analysis. We demonstrated this swept source imaging (SSI) in the rat inferior colliculus and obtained tonotopic maps with ~2 kHz resolution and 40 kHz bandwidth. The results were vastly superior to those obtained by conventional fMRI mapping approach and in excellent agreement with invasive findings. We applied SSI to examine tonotopic injury following developmental noise exposure and observed that the tonotopic organization was significantly disrupted. With SSI, we also observed the subtle effects of sound pressure level on tonotopic maps, reflecting the complex neuronal responses associated with asymmetric tuning curves. This in vivo and noninvasive technique will greatly facilitate future investigation of tonotopic plasticity and disorders and auditory information processing. SSI can also be adapted to study topographic organization in other sensory systems such as retinotopy and somatotopy.     

Prediction of memory rehabilitation outcomes in traumatic brain injury by using functional magnetic resonance imaging

Strangman GE, O'Neil-Pirozzi TM, Goldstein R, Kelkar K, Katz DI, Burke D, Rauch SL, Savage CR, Glenn MB. Prediction of memory rehabilitation outcomes in traumatic brain injury by using functional magnetic resonance imaging.

Objective

To evaluate the ability of functional magnetic resonance imaging (fMRI) measures collected from people with traumatic brain injury (TBI) to provide predictive value for rehabilitation outcomes over and above standard predictors.

Design

Prospective study.

Setting

Academic medical center.

Participants

Persons (N=54) with TBI greater than 1 year postinjury.

Intervention

A novel 12-session group rehabilitation program focusing on internal strategies to improve memory.

Main Outcome Measure

The Hopkins Verbal Learning Test−Revised (HVLT-R) delayed recall score.

Results

fMRI measures were collected while participants performed a strategically directed word memorization task. Prediction models were multiple linear regressions with the following primary predictors of outcome: age, education, injury severity, preintervention HVLT-R, and task-related fMRI activation of the left dorsolateral and left ventrolateral prefrontal cortex (VLPFC). Baseline HVLT-R was a significant predictor of outcome (P=.007), as was injury severity (for severe vs mild, P=.049). We also found a significant quadratic (inverted-U) effect of fMRI in the VLPFC (P=.007).

Conclusions

This study supports previous evidence that left prefrontal activity is related to strategic verbal learning, and the magnitude of this activation predicted success in response to cognitive memory rehabilitation strategies. Extreme under- or overactivation of VLPFC was associated with less successful learning after rehabilitation. Further study is necessary to clarify this relationship and to expand and optimize the possible uses of functional imaging to guide rehabilitation therapies.     

Examination of the role of the cerebral cortex in the perception of pain using functional magnetic resonance imaging

In the following review we outline several of the unique difficulties associated with designing and interpreting functional imaging studies of pain perception. Unlike other sensory modalities, the cortical processing of pain is unique, as is the pain experience itself. Unlike other sensory systems, pain processing does not take place in one dedicated region of the cortex. Rather, nociceptive cells are sparsely distributed through the somatosensory cortex. Further, pain is singular in that it has both sensorydiscriminative and affective-motivational components, which are probably subserved by different neuroanatomic substrates. Finally, abnormal pain sensation, such as neuropathic pain syndromes, may have different or additional mechanisms that require special consideration. We have illustrated these points with examples from our own work on acute pain and secondary mechanical hyperalgesia, and work from other laboratories.     

^99mTc-MIBI双时相显像在原发性甲状旁腺功能亢进症术前定位诊断中的价值

目的 对99mTc-MIBI双时相显像与颈部超声和颈部CT在原发性甲状旁腺功能亢进症术前定位诊断价值进行对比研究.方法 回顾性分析了44例经病理确诊为原发性甲状旁腺功能亢进症患者,术前甲状旁腺激素检测结果并将术前的99mTc-MIBI双时相显像、颈部超声及颈部CT检查结果进行对比分析.结果 甲状旁腺激素检出率为100%,但不可进行定位诊断;99mTc-MIBI双时相显像、颈部超声及颈部CT均可进行定位诊断;99mTc-MIBI双时相显像检出率(93.18%)分别高于颈部超声及颈部CT检出率(63.64%,61.9%),差异有统计学意义(P<0.05);颈部超声与颈部CT检出率,差异无统计学意义(P>0.05).结论 99mTc-MIBI双时相显像在原发性甲状旁腺功能亢进症中有较好的术前定位诊断价值.     

疼痛的脑功能MRI研究进展

功能MRI(f MRI)是一种无创性的功能成像技术,近年来被广泛应用于疼痛方面的研究,使得人们对疼痛的生理有了进一步的认识。作者通过对不同类型疼痛的分析,从痛觉中枢的定位、临床疼痛的f MRI研究及疼痛治疗等方面综述了近年关于疼痛的脑f MRI研究进展。     

Wavelets and functional magnetic resonance imaging of the human brain

The discrete wavelet transform (DWT) is widely used for multiresolution analysis and decorrelation or "whitening" of nonstationary time series and spatial processes. Wavelets are naturally appropriate for analysis of biological data, such as functional magnetic resonance images of the human brain, which often demonstrate scale invariant or fractal properties. We provide a brief formal introduction to key properties of the DWT and review the growing literature on its application to fMRI. We focus on three applications in particular: (i) wavelet coefficient resampling or "wavestrapping" of 1-D time series, 2- to 3-D spatial maps and 4-D spatiotemporal processes; (ii) wavelet-based estimators for signal and noise parameters of time series regression models assuming the errors are fractional Gaussian noise (fGn); and (iii) wavelet shrinkage in frequentist and Bayesian frameworks to support multiresolution hypothesis testing on spatially extended statistic maps. We conclude that the wavelet domain is a rich source of new concepts and techniques to enhance the power of statistical analysis of human fMRI data.     

Enhanced spatial localization of neuronal activation using simultaneous apparent-diffusion-coefficient and blood-oxygenation functional magnetic resonance imaging

Functional MRI (fMRI) can detect blood oxygenation level dependent (BOLD) hemodynamic responses secondary to local neuronal activity. The most commonly used method for detecting fMRI signals is the gradient-echo echo-planar imaging (EPI) technique because of its sensitivity and speed. However, it is known that much of the signal obtained with this approach arises from large veins, with additional contribution from the capillaries and venules. Early experiments using diffusion-weighted gradient-echo EPI have suggested that intravoxel incoherent motion (IVIM) weighting can selectively attenuate contributions from large vessels based on the differences in the mobility of the blood within them, thereby revealing the contributions from hemodynamic changes in capillaries, which are in close spatial proximity to the activated neural tissue. Using this differential sensitivity of the various neurovascular compartments to IVIM weighting, we present a new approach for deriving functional maps of neural activity. This method is based on task-induced changes of the apparent diffusion coefficients (ADC), a signal that we demonstrate is generated in vascular compartments that only partially overlap with those generating the BOLD signal. The approach allows both the ADC-based maps and the more commonly used BOLD-based maps to be acquired simultaneously. The spatial overlap between these maps can be used to create composite maps that permit improved localization of the underlying neuronal activity patterns by identifying signals generated in those vascular components that are in closest proximity to the active neuronal populations of interest.     

不同颜色光刺激视皮层脑功能成像研究

目的：利用功能性磁共振成像（fMRI）研究不同颜色光的变化在视皮层的信号强度的反应。资料与方法：48名受试者均接受红、绿、蓝3种颜色光的刺激。运用功能成像分析软件（AFNI软件）对原始数据进行处理,计算机自动产生出所选层面的时间信号强度相关图,并用统计学方法对图像进行比较。结果：48名受试者接受刺激后在双侧枕叶视皮层均有兴奋区,绿光刺激的平均血氧水平依赖（BOLD）信号强度比红光刺激增强17.5％左右（P<0．05）,而蓝光刺激的平均BOLD信号强度比绿光刺激增强9.6%左右（P<0．05）。同时发现右侧光刺激的平均BOLD信号强度比左侧光刺激增强18％左右（P<0．05）,此外脑组织兴奋还见于外侧膝状体、上丘、脑干的顶盖前区、顶叶皮层等。结论：通过对fMRI图像进行统计学分析,证实在光的刺激下枕叶视皮层血流信号增强,3种颜色光刺激中对蓝光最敏感,红光敏感性最弱,并且右侧信号变化比左侧强。