被动手运动fMRI在中央区胶质瘤患者术前定位有效性的应用研究

目的 探讨基于血氧水平依赖(BOLD)功能磁共振成像(fMRI)的被动手运动刺激对中央区胶质瘤运动功能区术前定位的有效性.方法 选取病灶位于中央区的胶质瘤患者15例,分别对患者进行主动手运动及被动手运动的任务刺激,采用独立成分分析方法观察运动功能区的激活范围及强度的变化.结果 被动手运动与主动手运动fMRI激活范围及强...     

运动皮层的功能磁共振成像研究

目的　用MR血氧水平依赖性成像技术 (BOLD)研究正常人及癫痫、脑肿瘤患者对指运动皮层的功能磁共振成像 (fMRI)。方法　 3 4例受试者 ,其中 8例正常志愿者 ,2 0例癫痫患者 ,6例脑肿瘤患者 ,行右手、左手对指运动共 43次 ,采用BOLD技术进行相应脑功能区成像。结果　所有受试者均能在MR脑功能检查中表现出局部脑功能活动区规律的信号时间变化曲线 ,并得以清晰成像。功能区附近的占位病变可造成局部功能区的移位和缩小等改变 ,原发性癫痫患者未见有对指运动功能区的明显改变。结论　BOLD -fMRI在活体人脑对指运动的功能区定位方面是一个有效的方法。对需实施手术的颅内占位病变进行BOLD -fMRI检查对指导手术有价值。需改进癫痫患者的脑功能研究 ,进行更有效的相关功能刺激     

人脑视皮质功能MRI的初步研究及临床应用

目的：本实验应用功能磁共振成像（fMRI）的回波平面（EPI）技术,着重研究了人脑视皮质的血氧水平依赖（BOLD）的功能磁共振成像。方法：本实验包括对36名正常健康志愿者及17例具有枕区病变患者的fMRI研究。在刺激和静止2种对比条件下采集枕区的回波平面图像。结果：主要视皮质位于双侧距状裂两侧 ,属于布劳德曼（Brodmann)17区。3例具有距状裂附近病变的患者的视皮质由于病变的占位效应而发生移位。结论：fMRI可用于在活体上脑上研究各功能区活动。视觉刺激下的fMRI可对人脑视皮质初步定位。由于病变占位效应的影响,病变周围的功能活动区常发生变形或移位。     

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.     

BOLD—fMRI在视觉研究中的应用

BOLD—fMRI是利用磁共振成像技术探测大脑在不同刺激条件下，不同脑功能区神经活动相关生理变化的实验方法。它可以无创、直观地反映活体大脑功能，是研究脑功能相关视觉问题的一项新技术。对BOLD—fMRI的基本原理、技术特点及其在视觉研究中的应用做一综述。     

磁共振脑功能成像在神经外科手术前后的应用价值

目的探讨功能性磁共振成像(fMRI)对手术前、后颅内病变累及运动中枢及其程度的诊断价值。方法选择45例经手术、病理证实的颅内占位性病变患者作为功能组,另20例颅内占位性病变手术患者为对照组;采用1.5T超导型MR成像仪,对功能组手术前、后行常规MRI及fMRI,对照组仅行常规MRI。结果45例功能组被检者均在脑fMRI中表现出局部的脑功能活动激活区,其中有22例运动皮层中枢的位置有不同程度移位,有23例运动皮层中枢未见明显移位改变;但手指运动功能区的分布并不会随病变类型而发生改变。病灶距功能区的距离与术前肌力呈正相关(r=0.553,P<0.001);与术后肌力无相关性(r=0.059,P>0.05);距离与肌力差呈负相关(r=-0.570,P<0.001)。术后有19例fMRI显示功能支配区较术前有不同程度增大;45例中无一例术后肌力降低,而对照组有5例(5/20)术后肌力降低。对照组手术前后肌力差平均值为(-0.05±0.69)级,功能组手术前后肌力差为(0.31±0.47)级,两者比较差异有统计学意义(t=2.473,P=0.016)。结论平均血氧水平依赖fMRI能清楚显示手运动皮层功能区,fMRI在术前提供了病变是否侵犯手运动皮质功能区的信息,为术中最大限度地保留功能区、避免和减少手术后并发症提供了客观依据;术前功能成像的应用对手术方案的制定及术后患者的功能恢复评估起指导作用。     

听觉性语言刺激的功能磁共振成像研究

目的用MR血氧水平依赖性(BOLD)技术研究听觉语言的功能磁共振成像(fMRI)。资料与方法23例受试者，其中正常志愿者14例，脑肿瘤患者6例，脑外伤软化灶形成患者3例。进行听觉性语言刺激共25次，采用BOLD技术进行相应脑功能区成像。结果所有受试者均能在MRI检查中表现出局部脑功能活动区规律的信号强度-时间变化曲线，并获得较清晰的图像。功能区附近的占位病变可造成局部功能区的移位和缩小等改变。结论BOLD-fMRI在活体人脑听觉语言的功能区定位方面是一种有效的方法。对需实施手术的颅内占位。病变进行BOLD-MRI检查对指导手术有价值。     

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.     

初级皮质运动区和锥体束的可视化研究及应用

目的探讨基于血氧水平依赖功能磁共振成像(BOLD-fMRI)和弥散张量成像(DTI)的功能神经导航技术在神经外科手术中对脑功能区进行显微镜下可视化的可行性。方法连续收集2009年2月-2010年7月初级运动皮质及锥体束附近病变患者278例,男156例,女122例,年龄40.7±15.9(7~79)岁。278例中胶质瘤231例,转移瘤5例,脑膜瘤16例,海绵状血管瘤18例,动静脉畸形2例,血管内皮细胞瘤1例,生殖细胞瘤3例,淋巴细胞瘤2例,均在功能神经导航下行手术切除。术前应用BOLD-fMRI及DTI技术进行扫描,通过导航工作站重建手运动区和锥体束并将导航影像投射至手术显微镜,用于镜下导航。比较患者术前及术后的肌力、运动功能及KPS评分,并统计手术并发症发生情况。结果 278例患者中217例(78.1%)病变切除≥95%,246例(88.5%)病变切除≥90%,259例(93.2%)病变切除≥80%;术后1周内神经功能障碍加重发生率为22.3%(62/278),随访1~6个月神经功能障碍发生率为6.8%(19/278)。结论在神经外科手术中应用fMRI及DTI结合功能神经导航对脑功能区进行显微镜下可视化是可行的,可最大限度地切除病变,减轻神经功能损伤,有利于术后功能恢复。     

中央区良性占位病变手术前后手运动及感觉功能区的fMRI研究

目的 探讨中央区良性占位病变患者手术前后手运动及感觉功能区功能磁共振成像(fMRI)的变化特征及临床价值.资料与方法 对位于或邻近脑中央区的17例良性占位病变患者手术前后1周行fMRI检查,刺激方式为对指运动及触刷,共3个周期.经SPM软件处理得出激活图和感兴趣区激活体积.结果 术前功能区主要表现为移位变形,激活区体积缩小.术后1周内复查,功能区移位有所恢复,功能区激活体积无明显改变(P＞0.05).结论 中央区良性占位病变周围功能区手术前后主要产生体积、形态及解剖位置的改变.术后1周功能区体积变化不明显.     

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.     

Functional magnetic resonance imaging for neurosurgical planning in neurooncology

Functional magnetic resonance imaging (fMRI) is a non-invasive technique that is widely available and can be used to determine the spatial relationships between tumor tissue and eloquent brain areas. Within certain limits, this functional information can be applied in the field of neurosurgery as a pre-operative mapping tool to minimize damage to eloquent brain areas. In this article, we review the literature on the use of fMRI for neurosurgical planning. The issues addressed are: (1) stimulation paradigms, (2) the influence of tumors on the blood oxygenation level-dependent (BOLD) signal, (3) post-processing the fMRI time course, (4) integration of fMRI results into neuronavigation systems, (5) the accuracy of fMRI and (6) fMRI compared to intra-operative mapping (IOM).     

Real-Time Motor Cortex Mapping for the Safe Resection of Glioma: An Intraoperative Resting-State fMRI Study

BACKGROUND AND PURPOSE:Resting-state functional MR imaging has been used for motor mapping in presurgical planning but never used intraoperatively. This study aimed to investigate the feasibility of applying intraoperative resting-state functional MR imaging for the safe resection of gliomas using real-time motor cortex mapping during an operation.MATERIALS AND METHODS:Using interventional MR imaging, we conducted preoperative and intraoperative resting-state intrinsic functional connectivity analyses of the motor cortex in 30 patients with brain tumors. Factors that may influence intraoperative imaging quality, including anesthesia type (general or awake anesthesia) and tumor cavity (filled with normal saline or not), were studied to investigate image quality. Additionally, direct cortical stimulation was used to validate the accuracy of intraoperative resting-state fMRI in mapping the motor cortex.RESULTS:Preoperative and intraoperative resting-state fMRI scans were acquired for all patients. Fourteen patients who successfully completed both sufficient intraoperative resting-state fMRI and direct cortical stimulation were used for further analysis of sensitivity and specificity. Compared with those subjected to direct cortical stimulation, the sensitivity and specificity of intraoperative resting-state fMRI in localizing the motor area were 61.7% and 93.7%, respectively. The image quality of intraoperative resting-state fMRI was better when the tumor cavity was filled with normal saline (P = .049). However, no significant difference between the anesthesia types was observed (P = .102).CONCLUSIONS:This study demonstrates the feasibility of using intraoperative resting-state fMRI for real-time localization of functional areas during a neurologic operation. The findings suggest that using intraoperative resting-state fMRI can avoid the risk of intraoperative seizures due to direct cortical stimulation and may provide neurosurgeons with valuable information to facilitate the safe resection of gliomas.

Mapping the motor cortex before and during tumor resection is of great importance to minimize the risks of postoperative neurologic sequelae. Direct cortical stimulation (DCS) is an invasive procedure to locate the function of specific brain regions. Due to its simplicity, DCS is considered the clinical criterion standard for mapping brain function and has demonstrated efficacy in optimizing glioma resection.^1,2 However, as an invasive approach, DCS requires a surgical team with rich experience. DCS also has the risk of after discharges, which can induce seizures and result in the inaccurate localization of cortical areas.³Blood oxygen level–dependent (BOLD) functional MR imaging, a task-based brain functional mapping method, has been well-established for localizing the brain functional area for presurgical planning. BOLD fMRI is of great importance in helping decrease morbidity due to a neurologic operation⁴ and has been integrated into neuronavigation systems to localize the motor area during an operation.⁵ Nonetheless, brain shifting during an operation might reduce the accuracy of preoperative imaging and affect the clinical consequences.⁶The emergence of intraoperative MR imaging (iMRI) has ushered in a new era in brain tumor neurosurgery.⁷ Real-time structural imaging and diffusion tensor imaging have provided neurosurgeons with valuable information regarding whether and where tumor residues persist after resection and even the relationship between the tumor/tumor cavity and peritumoral tracts.^8,9 The use of an iMRI navigation system can reliably compensate for the effects of brain shifting.⁶ We have recently reported intraoperative motor mapping with fMRI for the first time; in this procedure, awake intraoperative fMRI was used to localize the sensorimotor areas during awake craniotomy.¹⁰ Cooperation of the patient under specific tasks and complicated surgical procedures is essential for successful mapping. Therefore, task-induced brain mapping cannot be achieved with the patient under general anesthesia.Resting-state fMRI (R-fMRI) has recently been used to identify the motor cortex without a task stimulus.¹¹ This technique has been used in preoperative motor mapping in patients with brain tumors.^12–14 Our previous study demonstrated the accuracy of preoperative R-fMRI (pR-fMRI) for motor area localization by DCS before tumor resection.¹³ However, the study was based on pR-fMRI and lacked real-time information regarding the relationship between the tumor cavity/residual and the motor cortex, which might have affected the conclusion of whether further resection is safe.To our knowledge, functional connectivity based on intraoperative resting-state fMRI (iR-fMRI) has not been applied to real-time motor cortex mapping during an operation. The purpose of this study was to investigate the feasibility and validity of applying iR-fMRI to neurosurgical mapping. The sensitivity and specificity of iR-fMRI in mapping the motor cortex were assessed and compared with those of DCS. The optimum iR-fMRI protocol for better intraoperative imaging quality was also studied.     

Clinical applications of functional MRI at 1.0 T: motor and language studies in healthy subjects and patients

In this article we describe clinical applications of functional MRI (fMRI) at 1.0 T. All experiments were performed on a commercially available 1.0-T system (Magnetom Impact Expert, Siemens AG, Erlangen, Germany) using a blood oxygen level-dependent (BOLD)-sensitive multi-slice EPI technique (TE 66 ms, 4 mm slice thickness, 210 mm field of view, 64 × 64 acquisition matrix). Different paradigms for localization of the motor cortex and for language lateralization were tested in healthy subjects and patients. Methodological considerations concerning the development of the paradigms are also described. In all healthy subjects, motor activation elicited BOLD signal changes in the sensorimotor cortex, permitting identification of primary motor and sensory cortical areas. Furthermore, focal activation of different cortical areas by a language task was possible in 6 of 10 subjects. Nineteen motor studies were performed in 18 patients with supratentorial lesions, in most cases prior to neurosurgical procedures. In 14 studies, fMRI results demonstrated the localization of the motor hand areas relative to the lesion. The results proved valuable for preoperative planning and contributed to therapeutical decisions. We conclude that functional MRI for clinically relevant applications, such as localization of motor and language function, is feasible even at a field strength of 1.0 T without dedicated equipment. Received: 5 May 1998; Revision received: 1 July 1998; Accepted: 13 July 1998     

Mapa cortical y subcortical del lenguaje. Correlación de la resonancia magnética funcional y tractografía en 3 T con la estimulación intraoperatoria cortical y subcortical en tumores cerebrales localizados en áreas elocuentes

ObjectiveTo describe the detection of cortical areas and subcortical pathways involved in language observed in MRI activation studies and tractography in a 3 T MRI scanner and to correlate the findings of these functional studies with direct intraoperative cortical and subcortical stimulation.Material and methodsWe present a series of 14 patients with focal brain tumors adjacent to eloquent brain areas. All patients underwent neuropsychological evaluation before and after surgery. All patients underwent MRI examination including structural sequences, perfusion imaging, spectroscopy, functional imaging to determine activation of motor and language areas, and 3D tractography. All patients underwent cortical mapping through cortical and subcortical stimulation during the operation to resect the tumor. Postoperative follow-up studies were done 24 hours after surgery.ResultsThe correlation of motor function and of the corticospinal tract determined by functional MRI and tractography with intraoperative mapping of cortical and subcortical motor areas was complete. The eloquent brain areas of language expression and reception were strongly correlated with intraoperative cortical mapping in all but two cases (a high grade infiltrating glioma and a low grade glioma located in the frontal lobe). 3D tractography identified the arcuate fasciculus, the lateral part of the superior longitudinal fasciculus, the subcallosal fasciculus, the inferior fronto-occipital fasciculus, and the optic radiations, which made it possible to mark the limits of the resection. The correlation with the subcortical mapping of the anatomic arrangement of the fasciculi with respect to the lesions was complete.ConclusionThe best treatment for brain tumors is maximum resection without associated deficits, so high quality functional studies are necessary for preoperative planning.     

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。     

Comparison of functional MR imaging guidance to electrical cortical mapping for targeting selective motor cortex areas in neuropathic pain: a study based on intraoperative stereotactic navigation

PURPOSE: To assess the concordance between data from functional MR imaging (fMRI) guidance and the intraoperative electrical cortical mapping (iCM) in targeting selective motor cortex areas in refractory neuropathic pain. METHODS: Twenty-one patients (11 women and 10 men; mean age, 55.6 years) with refractory central (ischemic, 8 cases) and neuropathic pain (trigeminal neuropathy, 6 cases; syrinx/amputation/plexus trauma, 7 cases) underwent surgery for the implantation of an epidural electrode for chronic motor cortex stimulation (MCS) with general anesthesia and a frameless neuronavigation system used for the image-guided targeting procedure. All patients were studied by preoperative fMRI and epidural iCM with somatosensory evoked potentials and motor cortex stimulodetection. fMRI investigated systematically motor tasks of both hands and that related to the somatic area (foot or tongue) affected by pain. fMRI data were analyzed with the Statistical Parametric Mapping99 software (initial analysis threshold [AT] corresponding to P < .001), registered in the neuronavigation system and correlated intraoperatively with iCM. Matching of fMRI and iCM was specifically examined, focusing the study on hand mapping. RESULTS: Concordance between contours of fMRI activation area and iCM in precentral gyrus (mean distance, 3.8 mm) was found in 20/21 patients (95%). Because precision of iCM was suboptimal in 7 patients, concordance for more restrictive values of the AT (P < .0001) was found in only 13 of these 20 patients. Concordance was not found in one patient, as result of image distortion and residual motion artifact. CONCLUSIONS: In this study, fMRI guidance provides information that matches those of an independent functional method. These data illustrate the functional accuracy of fMRI guidance for the operative targeting of selective motor cortex areas in neuropathic pain.     

Intraoperative,real-time,functional MRI

Functional MRI (fMRI) methods have been demonstrated to noninvasively identify motor-sensory, visual, and other areas of eloquent cortex for guiding surgical intervention. Typically, fMRI data are acquired preoperatively during a conventional surgical planning MRI examination. Unlike direct cortical stimulation at the time of surgery, however, preoperative fMRI methods do not account for the potential movement of tissues (relative to the time of functional imaging) that may occur in the surgical suite as a direct result of the intervention. Recently, an MRI device has been demonstrated for use in the surgical suite that has the potential to reduce the extent of cortical exposure required for the intervention. However, the invasive requirements of cortical mapping may supersede the invasive requirements of the surgical intervention itself. Consequently, we demonstrate here a modification to the intraoperative MRI device that facilitates a noninvasive, real-time, functional MR examination in the surgical suite.     

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.