脑磁图在癫痫致痫灶及灶周脑功能区定位中的作用

目的：脑磁图是通过测定神经元兴奋产生的电流所伴随的磁场变化来确定异常放电的部位，了解其在癫痫致痫灶和痫灶周围脑功能区定位中的作用。资料来源：应用计算机检索Medline1998-07／2004-11与脑磁图和癫痫相关文章，检索词“Epilepsy，Magnetoencephalography，localization”，并限定文章语言种类为English。计算机检索VIP和CJFD1999／2004与脑磁图和癫痫相关的中文文章，检索词“癫痫，脑磁图，定位”。资料选择：对资料进行初审，纳入标准；①回顾性研究，无论是否设有对照组。②研究为随机抽样。开始查找全文，未排除是否为盲法。资料提炼：共收集到91篇相关文献（英文84篇，中文7篇）。54篇符合纳入标准。排除的37篇文章中34篇系重复研究，3篇为Meta分析。资料综合：54篇文章中14篇从偶极子定位方面阐述，13篇涉及脑磁图对癫痫患者手术前后评估，16篇与其他定位技术比较证明脑磁图的作用。11篇采取个案报道的形式证实脑磁图的定位价值。从中选取13篇有代表性的文献进行综述，认为作为无创性检测技术，脑磁图可检测到直径〈3．0mm的癫痫病理灶，分辨时相高达1．0ms，可以发现癫痫原发病灶与对侧对称位置出现的类似信号，即“镜像灶”，还能分辨发作间期一侧大脑半球的多个癫痫灶。脑磁图可用于癫痫发作期和发作间期致痫源的定位，还可对痫灶周围脑功能区进行定位，与脑电图比较，其使用更方便，更敏感。结论：脑磁图对各类癫痫的诊断，致痫灶、灶周脑功能区的定位，癫痫镜像灶的辨别具有明显的优势和广泛的应用前景。     

脑磁图在癫痫致痫灶及灶周脑功能区定位中的作用

目的:脑磁图是通过测定神经元兴奋产生的电流所伴随的磁场变化来确定异常放电的部位,了解其在癫痫致痫灶和痫灶周围脑功能区定位中的作用。资料来源:应用计算机检索Medline1998-07/2004-11与脑磁图和癫痫相关文章,检索词“Epilepsy,Magnetoencephalography,localization”,并限定文章语言种类为English。计算机检索VIP和CJFD1999/2004与脑磁图和癫痫相关的中文文章,检索词“癫痫,脑磁图,定位”。资料选择:对资料进行初审,纳入标准:①回顾性研究,无论是否设有对照组。②研究为随机抽样。开始查找全文,未排除是否为盲法。资料提炼:共收集到91篇相关文献(英文84篇,中文7篇)。54篇符合纳入标准。排除的37篇文章中34篇系重复研究,3篇为Meta分析。资料综合:54篇文章中14篇从偶极子定位方面阐述,13篇涉及脑磁图对癫痫患者手术前后评估,16篇与其他定位技术比较证明脑磁图的作用,11篇采取个案报道的形式证实脑磁图的定位价值。从中选取13篇有代表性的文献进行综述,认为作为无创性检测技术,脑磁图可检测到直径<3.0mm的癫痫病理灶,分辨时相高达1.0ms,可以发现癫痫原发病灶与对侧对称位置出现的类似信号,即“镜像灶”,还能分辨发作间期一侧大脑半球的多个癫痫灶。脑磁图可用于癫痫发作期和发作间期致痫源的定位,还可对痫灶周围脑功能区进行定位,与脑电图比较,其使用更方便,更敏感。结论:脑磁图对各类癫痫的诊断,致痫灶、灶周脑功能区的定位,癫痫镜像灶的辨别具有明显的优势和广泛的应用前景。     

术中皮层脑电监测对难治性癫痫致痫灶定位的价值

目的:探讨癫痫手术中皮层脑电图监测指导切除致痫灶的应用价值.方法:2007年3月至2010年8月期间36例难治性癫痫患者经严格术前评估后,开颅手术治疗.术中在EcoG引导下精确定位致痫灶,确定手术范围,手术切除病灶及其周围的致痫灶.结果:术后随访后随访12～ 449个月.根据Engel疗效分级标准进行疗效评价,Ⅰ级22例,Ⅱ级8例,Ⅲ级4例,Ⅳ级2例,有效率94.4％,显效率83.3％.结论:术中应用EcoG监测能大大提高致痫灶空间定位的准确性,有效地指导癫痫手术.EcoG在不同病理类型的致痫灶中的诊断价值不尽相同,皮质发育不良的术中EcoG应用前景广阔.     

应用脑磁图对人脑初级体感皮质功能定位的研究

目的　通过脑磁图确定脑初级体感皮质的位置。方法　对 16名右利手健康受试者腕部正中神经进行电刺激 ,引起支配手的脑初级感觉皮质兴奋 ,脑初级感觉皮质的兴奋产生微弱的颅外磁场 ,用脑磁图机对这个微弱的颅外磁场进行测量。脑磁图检查后 ,受试者进行MRI检查 ,扫描序列为SE序列 ,矢状T1WI。结果　所有受试者均出现M 2 0波峰及M 3 5波峰 ,只有 2例出现明显的M 60波峰。将同一受试者M 2 0波峰及M 3 5波峰的等电流偶极与MRI叠加 ,即可明确显示手区初级体感皮质在左、右侧半球的位置。同一受试者M 2 0偶极位置与相应半球的M 3 5偶极位置相近。结论　将脑磁图获得的脑电生理学资料与MRI获得的解剖学资料叠加到一起所得到的磁源性影像可准确地确定脑的手区初级体感皮质的位置。     

ECOG评估PET对致痫灶定位的准确性

目的 :用皮层脑电(Electroencephalography,ECOG)评估 PET对致痫灶定位诊断的准确性。方法 :36例经CT和MR检查除外脑部肿瘤及脑血管畸形的癫痫病人 ,经正电子发射断层扫描(Positronemissiontomography,PET)检查定位后 ,进行颅骨钻孔 ,放置条状电极片 ,然后进行ECOG描记 ,评估PET对致痫灶定位诊断的准确性。结果 :PET对致痫灶定位诊断的准确率为93 %。结论 :PET是目前准确率较高的无创性致痫灶定位诊断方法     

皮层脑电图监测下致痫灶切除治疗难治性癫痫的护理35例

1993年8月～2000年12月,我院采用皮层脑电图监测下致痫灶切除治疗35例难治性癫痫,取得了满意的效果,现将护理体会报告如下.     

瑞芬太尼联合异丙酚靶控输注在额叶功能区致痫灶切除术唤醒麻醉中的应用

目的：观察瑞芬太尼联合异丙酚靶控输注在额叶功能区致痫灶切除手术唤醒麻醉中的效果。方法随机将20例择期行额叶功能区致痫灶切除术的患者分为2组：瑞芬太尼联合异丙酚靶控输注组（R组）和芬太尼间断静注联合异丙酚靶控输注组（F组），每组各10例，比较2组患者的唤醒时间、血流动力学变化、唤醒期间清醒程度（BIS值）和术野质量（VAS评分），并且观察2组患者唤醒期间并发症的发生率。结果 R组唤醒时间明显小于F组（P＜0.05），R组唤醒和脑电刺激时血压和基础值比较差异无统计学意义（P＞0.05），而F组唤醒和脑电刺激时血压明显高于基础值（P＜0.05）。插喉罩，上头架，切皮，唤醒时，脑电刺激时R组血压和心率明显低于F组（P＜0.05）。术中唤醒5、10 min，R组清醒程度明显高于F组（P＜0.05），2组术野质量评分差异无统计学意义。在术中并发症方面，R组不良反应发生率显著低于F组。结论瑞芬太尼联合异丙酚靶控输注在额叶功能区致痫灶切除术唤醒麻醉中能取得更满意的效果。     

磁共振波谱和正电子发射计算机断层扫描对颞叶致痫灶定位价值的比较

目的 对比研究高场强MRS和18F-FDG PET/CT脑代谢显像对颞叶致痫灶定位的价值.方法 62例资料完整的颞叶癫痫(TLE)患者行常规MRI、1H-MRS及18F-FDG PET/CT检查,定位结果与颅内电极脑电图及术后病理对照,行Kappa一致性检验,对比评价常规MRI、1H-MRS、18F-FDG PET/C...     

颅脑术后继发癫痫患者实施致痫灶切除术的护理

目的探讨颅脑术后继发癫痫患者实施致痫灶切除术的护理措施。方法 2005年1月至2006年5月,解放军空军航空医学研究所附属医院对25例颅脑术后继发性癫痫患者采用二次开颅手术切除致痫灶治疗并实施有效护理。结果 25例患者手术后恢复均顺利,无死亡。术后随访6~7年,25例患者中发作控制EngleⅠ级18例、Ⅱ级5例、Ⅲ级2例;18例(72%)无发作,其中9例已停药。结论二次开颅手术治疗颅脑术后继发癫痫疗效满意,科学的护理是手术成功的保证。     

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.     

Localization of Language-Related Cortex withO-Labeled Water PET in Patients with Gliomas

Measurement of relative cerebral blood flow (CBF) with¹⁵O-labeled water PET has been widely used for brain mapping experiments on language functions in normal volunteers and patients with epilepsy. We focused on the question of whether PET during speech activation is an appropriate method for noninvasive determination of language-related cortex in patients with brain tumors. Furthermore, the suitability of the method for determination of hemispheric language dominance was examined and compared to the results of the Edinburgh Handedness Inventory. Ten right-handed and six left-handed patients with gliomas were examined prior to surgery while repeatedly performing word repetition and verb generation tasks. A set of volumes of interest (VOIs) was drawn on coregistered MRI in order to account for anatomic variability as well as anatomical alterations due to tumor mass effect. Repetition of nouns did not produce significant hemispheric differences. During stimulation by verb generation, reliable lateralized activations of Broca's area and supplementary motor area were detected in all right-handed patients. Of the left-handed patients, two showed clear right lateralization, two activated Broca's area bilaterally, and two had a pattern similar to that of right-handers. Patients with bilateral activations showed the strongest tendency toward bihandedness according to the handedness inventory. Lateralization of supplementary motor area in left-handers corresponded to lateralized activity in Broca's area. Tumors in the vicinity of language-related regions did not alter activation responses. In conclusion, measurement of CBF changes during verb generation permits identification of language-related areas in patients with gliomas with strong lateralization related to hemispheric dominance. These findings may be of particular clinical interest for left-handed patients.     

Asymmetry in the Human Motor Cortex and Handedness

Handedness is one of the most obvious functional asymmetries, but its relation to an anatomical asymmetry of the hand representation area in the motor cortex has not been demonstrated. This would be a crucial test for the hypothesis of structure–function correlation in cortical motor organization. Using magnetic resonance morphometry, we show for the first time that the depth of the central sulcus is related to handedness. In right-handers, the left central sulcus is deeper than the right, and vice versa in left-handers. Macrostructural asymmetry is complemented by a microstructural left-larger-than-right asymmetry in neuropil volume (i.e., tissue compartment containing dendrites, axons, and synapses) in Brodmann's area 4. These asymmetries suggest that hand preference is associated with increased connectivity (demonstrated by an increased neuropil compartment in left area 4) and an increased intrasulcal surface of the precentral gyrus in the dominant hemisphere.     

Clinical Evaluation of Synthetic Aperture Sequential Beamforming Ultrasound in Patients with Liver Tumors

Medical ultrasound imaging using synthetic aperture sequential beamforming (SASB) has for the first time been used for clinical patient scanning. Nineteen patients with cancer of the liver (hepatocellular carcinoma or colorectal liver metastases) were scanned simultaneously with conventional ultrasound and SASB using a commercial ultrasound scanner and abdominal transducer. SASB allows implementation of the synthetic aperture technique on systems with restricted data handling capabilities due to a reduction in the data rate in the scanner by a factor of 64. The image quality is potentially maintained despite the data reduction. A total of 117 sequences were recorded and evaluated blinded by five radiologists from a clinical perspective. Forty-eight percent of the evaluations were in favor of SASB, 33% in favor of conventional ultrasound and 19 % were equal, that is, a clear, but non-significant trend favoring SASB over conventional ultrasound (p = 0.18), despite the substantial data reduction.     

PET与伽玛PET在癫痫灶定位中的应用

就正电子发射断层成像 (PET)与伽玛PET在癫痫灶定位中的应用作一介绍     

Comparison of Electrical and Ultrasound Neurostimulation in Rat Motor Cortex

Ultrasound (US) is known to non-invasively stimulate and modulate brain function; however, the mechanism of action is poorly understood. This study tested US stimulation of rat motor cortex (100 W/cm², 200?kHz) in combination with epidural cortical stimulation. US directly evoked hindlimb movement. This response occurred even with short US bursts (3?ms) and had short latency (10?ms) and long refractory (3?s) periods. Unexpectedly, the epidural cortical stimulation hindlimb response was not altered during the 3-s refractory period of the US hindlimb response. This finding suggests that the US refractory period is not a general suppression of motor cortex, but rather the recovery time of a US-specific mechanism.     

fMRI Evaluation of Somatotopic Representation in Human Primary Motor Cortex

We used fMRI to map foot, elbow, fist, thumb, index finger, and lip movements in 30 healthy subjects. For each movement type confidence intervals of representational sites in the primary motor cortex (M1) were evaluated. In order to improve the precision of their anatomical localization and to optimize the mapping of cortical activation sites, we used both the assessment of locations in the conventional 3D system and a 2D projection method. In addition to the computation of activation maxima of activation clusters within the precentral gyrus, centers of gravity were determined. Both methods showed a high overlap of their representational confidence intervals. The 2D-projection method revealed statistically significant distinct intralimb locations, e.g., elbow versus index finger movements and index finger versus thumb movements. Increased degree of complexity of finger movements resulted in a spread of the somatotopic location toward the arm representation. The 2D-projection method-based fMRI evaluation of limb movements showed high precision and was able to reveal differences in intralimb movement comparisons. fMRI activation revealed a clear somatotopic order of movement representation in M1 and also reflected different degrees of complexity of movement.     

On Somatotopic Representation Centers for Finger Movements in Human Primary Motor Cortex and Supplementary Motor Area

We usedfunctional magnetic resonance imaging to examine the representation pattern for repetitive voluntary finger movements in the primary motor cortex (M1) and the supplementary motor area (SMA) of humans. Healthy right-handed participants performed repetitive individuated flexion-extension movements of digits 1, 2, and 3 using the dominant hand. Contralateral functional labeling for the group indicated a largely overlapping activation pattern in M1 and SMA for the three digits. Consistent with recent findings, the geographic activation center in M1 for each finger differed, and we found some evidence of a homunculus organization pattern in M1 and SMA, but only for the central location of the representations. However, the statistical power for the homunculus pattern was weak, and the distance separating the digit geographical centers was typically less than 15% of the entire extent of digit representations in M1 or SMA. While separations for digit representations occurred, the entire data set provided more support for the concept of distributed, overlapping representations than for a classic homunculus organization for voluntary finger movements.     

Identification of Abnormal Neuromagnetic Signatures in the Motor Cortex of Adolescent Migraine

(Headache 2010;50:1005‐1016) Objective.— To investigate the functional abnormalities of the motor cortices in children with migraine using magnetoencephalography (MEG) and a finger‐tapping task. Background.— Cortical hyperexcitability has been reported in adults with migraine using MEG. Many children with migraine report difficulty with motor functioning. There is no report on motor‐evoked magnetic activation in children with migraine using MEG and the latest signal processing methods. Methods.— Ten children with migraine (all female, 9 right‐handed and 1 left‐handed, aged 13‐17 years) and 10 age‐ and gender‐matched healthy children were studied with a 275‐channel MEG system. After hearing a unilateral, randomly presented sound cue (500 Hz, 30 milliseconds square tone), each subject immediately performed a brisk index finger tapping with either the right or the left index finger. The auditory stimuli consisted of 200 trials of square tone, 100 trials per ear, randomly distributed. The latency and amplitude of neuromagnetic responses were analyzed with averaged waveforms. Neuromagnetic sources were estimated using synthetic aperture magnetometry (SAM). SAM images were normalized for each participant for group comparison. Results.— In comparison with healthy children, children with migraine had prolonged latency of motor‐evoked magnetic response in the right hemispheres during left finger movement (62.33 ± 34.55 milliseconds vs 34.9 ± 17.29 milliseconds, P < .05). In addition, children with migraine had stronger activation in the motor cortex during right finger movement (8097.46 ± 5168.99 vs 4697.54 ± 3194.74, P < .05). Conclusions.— The results suggest that there are neurophysiological changes in the motor cortices of children with migraine that can be measured with neuromagnetic imaging techniques. The findings expand the ability to study the cerebral mechanisms of migraine using MEG and may facilitate the development of new therapeutic strategies in migraine treatment via alterations in cortical excitability.     

Observations of supra-glacial lakes in west Greenland using winter wide swath Synthetic Aperture Radar

Melt water gathered in supra-glacial lakes on the Greenland ice sheet contributes to reduced basal friction by the input of water from the surface to the bed during the melt season. Supra-glacial lakes change on both annual and inter-annual timescales. The high temporal resolution and moderate spatial resolution Moderate Resolution Imaging Spectroradiometer (MODIS) can be used to capture annual changes on the highly transient/fast-draining lakes. However, MODIS imagery lacks the ability to penetrate clouds. Using ENVISAT Synthetic Aperture Radar (SAR) winter images, we show that SAR images can be used to identify seasonal/inter-annual changes in the lake area. Furthermore, winter SAR images identify lakes obscured to optical data by ice and snow cover. However, the SAR imagery systematically failed to discriminate narrow lakes and lakes in corrugated topography. Thus, SAR images can be used as a complement to existing visible–near-infrared data but do not offer a viable replacement.