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。     

3T高场强功能MRI在脑功能区胶质瘤皮质电刺激手术中的应用

目的研究应用3T高场强功能MRI（fMRI）定位脑运动功能区，及在脑胶质瘤直接皮质电刺激手术中的指导作用。方法26例邻近或累及脑运动功能区的胶质瘤患者术前采用双手握拳刺激策略，根据血氧水平依赖（BOLD）原理进行功能成像。经工作站提供的BOLD功能图像分析软件包进行分析，获得脑运动功能区的激活图像，制定手术方案。所有患者均在唤醒麻醉下进行显微外科手术，在术前fMRI指导下利用直接皮质电刺激定位运动区。在保护脑功能不受损的前提下，最大程度地切除胶质瘤。术前、术后均行Karnofsky生活状态（KPS）评分，判断患者的状态。结果26例术前BOLD运动fMRI有23例获得良好的手运动脑功能区激活图像。患者在唤醒麻醉下，在术前fMRI指导下利用直接皮质电刺激快捷、准确定位初级运动皮质区，并且两者具有良好的一致性。同时术前fMRI提供术中未检测到的脑功能区的信息，相互补充。术前KPS评分80．0～90．0分患者21例（平均85．7分）术后恢复至平均95．2分，术前KPS评分40．0～70．0分患者5例（平均68．0分）术后恢复至平均90．0分。结论术前fMRI可活体和无创地描绘出脑运动功能区与肿瘤的功能解剖位置关系，优化手术方案，在唤醒麻醉下指导直接皮质电刺激定位运动区的手术，实现最大程度保护脑功能，并最大程度地切除肿瘤。     

运动相关大脑皮层的功能磁共振成像

目的 :应用功能磁共振成像技术对运动皮层在运动准备及执行阶段的功能活动分布进行研究。方法 :应用事件相关功能磁共振成像技术 ,记录 14名右利手健康受试者在序列手指运动过程中大脑皮层的功能活动 ,获得运动准备和运动执行阶段的脑激活图。结果 :双侧辅助运动区前部、双侧运动前区后部及双侧后顶叶前部在运动准备与执行过程均有激活。结论 :研究表明运动皮层存在于运动准备和执行阶段均有激活的脑功能区 ,事件相关功能磁共振成像技术可应用于脑活动机制的研究。     

急性期脑卒中患者和健康成人食指被动运动BOLD-fMRI

目的：对比分析急性期脑梗死患者与健康成人各运动相关脑区激活程度和方法的差异,探讨急性期脑梗死后运动功能变化的模式。方法：对12例基底节区急性期缺血性脑梗死患者（实验组）和与之相匹配的12例健康成人（对照组）进行食指被动运动BOLD-fMRI检查,然后应用SPM对功能图像进行处理分析,并选取初级感觉运动区（SM1）、次级感觉运动区（SM2）、运动前区（PM）、补充运动区（SMA）、扣带回运动区（CMA）及小脑作为兴趣区,观察两组受试者各运动相关脑区的激活情况,并对对侧SM1区的激活体积、激活率进行定量分析。结果：对照组主要激活对侧SM1区（激活体积中位数1006k,四分位间距1142k,激活率100％）,其它运动相关脑区激活次数较少,且激活体积相对较小;患者组主要激活对侧SM1区（激活体积中位数15k,四分位间距71k,激活率58．3％）,其它运动相关脑区偶尔或无激活。患者组对侧SM1激活率、激活体积均比对照组低（P〈0．05）。结论：BOLD-fMRI是一种研究脑梗死患者运动功能的有效方法。     

Organization of the human motor system as studied by functional magnetic resonance imaging.

Blood oxygenation level dependent functional magnetic resonance imaging (BOLD fMRI), because of its superior resolution and unlimited repeatability, can be particularly useful in studying functional aspects of the human motor system, especially plasticity, and somatotopic and temporal organization. In this survey, while describing studies that have reliably used BOLD fMRI to examine these aspects of the motor system, we also discuss studies that investigate the neural substrates underlying motor skill acquisition, motor imagery, production of motor sequences; effect of rate and force of movement on brain activation and hemispheric control of motor function. In the clinical realm, in addition to the presurgical evaluation of neurosurgical patients, BOLD fMRI has been used to explore the mechanisms underlying motor abnormalities in patients with neuropsychiatric disorders and the mechanisms underlying reorganization or plasticity of the motor system following a cerebral insult.     

中文语言活动区功能磁共振研究

目的　利用BOLD功能磁共振 ,初步探索国人说汉语时大脑语言相关功能区。方法　对 2 2名正常中国人 ,说中文句子状态下进行BOLD磁共振脑功能成像 ,探索其大脑语言活动皮层相关功能区。结果　说中文时激活的脑区包括 :两侧运动区 ,左右侧额下回 ,左右侧颞上回 ,左侧岛叶及左右侧小脑半球。结论　BOLD功能磁共振可显示中文大脑活动相关皮层 ,是无创性研究人类语言的有力武器     

Arterial spin labeling perfusion fMRI with very low task frequency.

Functional magnetic resonance imaging (fMRI) has become the most widely used modality for visualizing regional brain activation in response to sensorimotor or cognitive tasks. While the majority of fMRI studies have used blood oxygenation level-dependent (BOLD) contrast as a marker for neural activation, baseline drift effects result in poor sensitivity for detecting slow variations in neural activity. By contrast, drift effects are minimized in arterial spin labeling (ASL) perfusion contrast, primarily as a result of successive pairwise subtraction between images acquired with and without labeling. Recent data suggest that ASL contrast shows stable noise characteristics over the entire frequency spectrum, which makes it suitable for studying low-frequency events in brain function. The present study investigates the relative sensitivities of ASL and BOLD contrast in detecting changes in motor cortex activation over a spectrum of frequencies of experimental design, where the alternating period between the resting state and activation is varied from 30 s up to 24 hr. The results demonstrate that 1) ASL contrast can detect differences in motor cortex activation over periods of minutes, hours, and even days; 2) the functional sensitivity of ASL contrast becomes superior to that of BOLD contrast when the alternating period between the resting state and activation is greater than a few minutes; and 3) task activation measured by ASL tends to have less intersubject variability than BOLD contrast. The improved sensitivity of the ASL contrast for low task frequency and longitudinal studies, along with its superior power in group analysis, is expected to extend the range of experimental designs that can be studied using fMRI.     

Suppression of physiological eye movement artifacts in functional MRI using slab presaturation

Reduction of image-to-image signal fluctuations and imaging artifacts is important for fMRI studies. The imaging artifacts caused by respiration, cardiac pulsation, and gross head motion and the suppression of these artifacts have been studied for many years. However, the artifacts caused by eye movement and their effects on fMRI mapping are not well known. It is demonstrated in this report that involuntary eye movements during resting conditions can cause substantial signal fluctuations in the phase-encoding direction even for a fast echo-planar imaging sequence. An oblique slab presaturation technique is proposed for saturating the magnetization of eyes and suppressing the artifacts from eye movements with minimal signal loss of other brain tissues. The results show that the technique significantly reduces signal fluctuations and improves fMRI reliability for mapping functional activation in the human brain.     

Functional localization of brainstem and cervical spinal cord nuclei in humans with fMRI

BACKGROUND AND PURPOSE: To our knowledge, no published functional map of the human lower brainstem exists. Our purpose was to use 1.5-T functional MR imaging (fMRI) to visualize the location of cranial nerve (CN) nuclei and other pontine, bulbar, and cervical spinal cord nuclei by using specific sensory stimulation or motor performance. METHODS: We localized nuclei by using cross-correlation analysis of regional blood oxygen level-dependent (BOLD) signal intensity during specific motor and sensory procedures based on known functions of specific nuclei. Statistical parametric mapping (SPM) analysis was used for comparison. Head, cardiac, and respiratory motion artifact correction was applied. Histologic atlases aided localization. RESULTS: We obtained evidence of localization of the following nuclei by using tests, as follows: main trigeminal sensory (CN V), brushing the face; abducens (CN VI), left-right eye movement; facial (CN VII), smiling and lip puckering; hypoglossal (CN XII), pushing the tongue against the hard palate; nucleus ambiguus, swallowing; nucleus tractus solitarii (NTS), tasting a sweet-sour-salty-bitter mixture; nucleus cuneatus, finger tapping; and cervical spinal cord levels C1-C3, tongue movement to activate the strap muscles. Activation of cortical motor and sensory areas and somatosensory thalamus corresponded with the tasks and sites of brainstem activation. Head movement was minimal, typically less than 1 mm in all three axes. CONCLUSION: With 1.5-T fMRI, the CN nuclei of the pons and medulla, and other nuclei of the lower brainstem and cervical spinal cord, can be localized in awake humans with specific sensory stimulation or motor performance.     

Vascular space occupancy-dependent functional MRI by tissue suppression

PURPOSE: To measure the cerebral blood volume (CBV) dynamics during neural activation, a novel technique named vascular space occupancy (VASO)-based functional MRI (fMRI) was recently introduced for noninvasive CBV detection. However, its application is limited because of its low contrast-to-noise ratio (CNR) due to small signal change from the inverted blood. MATERIALS AND METHODS: In this study a new approach-VASO with tissue suppression (VAST)-is proposed to enhance CNR. This technique is compared with VASO and blood oxygenation level-dependent (BOLD) fMRI in block-design and event-related visual experiments. RESULTS: Based on acquired T(1) maps, 75.3% of the activated pixels detected by VAST are located in the cortical gray matter. Temporal characteristics of functional responses obtained by VAST were consistent with that of VASO. Although the baseline signal was decreased by the tissue suppression, the CNR of VAST was about 43% higher than VASO. CONCLUSION: With the improved sensitivity, VAST fMRI provides a useful alternative for mapping the spatial/temporal features of regional CBV changes during brain activation. However, the technical imperfectness of VAST, such as the nonideal inversion efficiency and physiological contaminations, limits its application to precise CBV quantification.     

Re-examine tumor-induced alterations in hemodynamic responses of BOLD fMRI: implications in presurgical brain mapping

Background Blood oxygenation level dependent (BOLD) fMRI is used for presurgical functional mapping of brain tumor patients. Abnormal tumor blood supply may affect hemodynamic responses and BOLD fMRI signals. Purpose To perform a multivariate and quantitative investigation of the effect of brain tumors on the hemodynamic responses and its impact on BOLD MRI signal time course, data analysis in order to better understand tumor-induced alterations in hemodynamic responses, and accurately mapping cortical regions in brain tumor patients. Material and Methods BOLD fMRI data from 42 glioma patients who underwent presurgical mapping of the primary motor cortex (PMC) with a block designed finger tapping paradigm were analyzed, retrospectively. Cases were divided into high grade (n = 24) and low grade (n = 18) groups based on pathology. The tumor volume and distance to the activated PMCs were measured. BOLD signal time courses from selected regions of interest (ROIs) in the PMCs of tumor affected and contralateral unaffected hemispheres were obtained from each patient. Tumor-induced changes of BOLD signal intensity and time to peak (TTP) of BOLD signal time courses were analyzed statistically. Results The BOLD signal intensity and TTP in the tumor-affected PMCs are altered when compared to that of the unaffected hemisphere. The average BOLD signal level is statistically significant lower in the affected PMCs. The average TTP in the affected PMCs is shorter in the high grade group, but longer in the low grade tumor group compared to the contralateral unaffected hemisphere. Degrees of alterations in BOLD signal time courses are related to both the distance to activated foci and tumor volume with the stronger effect in tumor distance to activated PMC. Conclusion Alterations in BOLD signal time courses are strongly related to the tumor grade, the tumor volume, and the distance to the activated foci. Such alterations may impair accurate mapping of tumor-affected functional areas when using conventional fixed models.     

Cortical intraoperative stimulation in brain tumors as a tool to evaluate spatial data from motor functional MRI

RATIONALE AND OBJECTIVE: The purpose of this prospective, double-blind study was to correlate motor functional MRI (fMRI) with cortical brain mapping by intraoperative stimulation using 3D reconstructed images of the surface of the brain, and to validate the spatial data of fMRI in patients with brain tumors. METHODS: Fourteen patients with tumors of the rolandic region underwent functional MR mapping of the hand region and subsequently cortical mapping before tumor resection. Data obtained with fMRI and brain mapping were not known previously by the neurosurgeon and by the neuroradiologist, respectively (double-blind study). RESULTS: In each case, the results of direct cortical mapping matched those obtained with fMRI, both positively and negatively, although the extent of the functional activations was larger than the area required to elicit the corresponding movement during intraoperative brain mapping. CONCLUSION: fMRI can be used before surgery to assess motor functional area in patients with rolandic tumors. More studies are needed to validate during surgery the real extent of fMRI activations.     

Functional MRI of human auditory cortex using block and event-related designs.

fMRI of human auditory cortex response to sinusoidal tones of 200, 1000, and 3000 Hz was evaluated using block design and conventional and "silent" event-related designs. Conventional event-related fMRI revealed the timecourse of the BOLD response (approximately 5 sec to peak, approximately 4 sec full-width-half-max, and approximately 14 sec recovery to baseline). Both event-related, but not block, designs provided evidence for tonotopic organization in auditory cortex. Sources of low-frequency activation were more lateral and anterior than the sources of high-frequency activation (P < or = 0.05). In the block designs, repeated rapid stimulus presentation and the co-incidence of scanner noise preclude definition of tonotopic organization revealed in event-related approaches. Magn Reson Med 45:254-260, 2001.     

Correlation between the amplitude of cortical activation and reaction time: a functional MRI study

OBJECTIVE: We sought to examine the correlation between reaction time and the amplitude of cortical activation during the performance of a visuomotor response-time task in a functional MRI (fMRI) experiment. We hypothesized that the fMRI blood oxygenation level-dependent (BOLD) amplitude may have a negative correlation with a subject's reaction time: the lower the amplitude within the cortical areas along the visuomotor pathway, the slower the response. A larger amplitude of the fMRI signal would reflect faster response times. SUBJECTS AND METHODS: During a single-event fMRI experiment, the reaction times (in milliseconds) of 32 right-handed subjects responding to a visual cue were recorded. Analysis of the single-event paradigm using Statistical Parametric Mapping (SPM99) was performed, activation maps were produced for each subject, and then a random effects group analysis was performed. The maximum amplitudes of cortical activation (percent signal change) in four activated cortical regions were estimated and tabulated. The regions of interest included were the right and left occipital visual cortices, the supplementary motor area, and the left sensorimotor area. Simple and multiple regressions were performed between the mean reaction times of the subjects and the BOLD amplitudes in each region of interest and for the composite region of interest. RESULTS: The results showed significant negative associations between the reaction times and maximum amplitudes in the right occipital, left occipital, and left sensorimotor area cortical regions (p < 0.05). However, no significant association was found between reaction times and the amplitude within the supplementary motor area. When the effects of age and sex on these associations were analyzed, we found that age had an impact on the results for individual regions of interest in the left occipital and left sensorimotor areas, but the composite amplitude of activation remained significantly correlated with reaction times. CONCLUSION: The degree of signal change in BOLD fMRI response of the right occipital, left occipital, and left sensorimotor areas reflects the speed of performance during the visuomotor response time task by the subject. Thus, the amplitude of activation can be used as one parameter to assess change in function.     

事件相关功能MRI在随意运动脑功能活动区协同作用研究中的应用

目的 应用事件相关功能磁共振成像（fMRI)技术，探讨手指运动时人脑功能活动区的协同作用。方法 选取44名健康受试者，应用信息提示－执行（CUE－GO）行为模式，成像应用GE Signa Iorizon 1.5T磁共振系统，所获数据在SUN与SGI工作站进行处理。结果 对侧初级运动皮层（M1），双侧辅助运动区（SMA）、运动前区（PMA）、基底节及小脑皮质等区域有明显激活。其中M1区时间－信号强度曲线呈典型单峰曲线；PMA、基底节、小脑皮质区的时间－信号强度曲线为双峰曲线。SMA又分为2个区，为位于前方的辅助运动前区（Pre-SMA)和后方固有区（SMA Proper)。Pre-SMA为双峰曲线，SMA Proper则为单峰曲线。各脑区的时间－信号强度曲线不完全相同。结论 （1）M1区为运动执行区；而其他脑区则参与运动准备及运动执行，且各脑区在其功能上有一定差异。（2）SMA、PMA、基底节及小脑皮质均为双侧激活，与传统理论略有差异。（3）事件相关fMRI技术具有较高的时间分辨率和空间分辨率。（4）脑内不同脑区、基底节及小脑间其功能活动具有协同作用。     

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     

Clinical functional MRI of sensorimotor cortex using passive motor and sensory stimulation at 3 Tesla

Purpose:

To establish a passive motor paradigm for clinical functional MRI (fMRI) that could be beneficial for patients with motor or attention deficits who are not able to perform active motor tasks.

Materials and Methods:

A novel standardized sensorimotor fMRI protocol was applied in 16 healthy volunteers at 3 Tesla (T) using active and passive motor tasks as well as sensory stimulation of hands and feet. Data analysis was carried out individually using a dynamic thresholding routine.

Results:

Active motor tasks yielded time efficient and robust blood‐oxygen‐level‐dependent (BOLD) signals in primary motor cortex. Noteworthy, it was possible to achieve equal activation levels within identical anatomical localization for passive and active motor tasks with these paradigms.

Conclusion:

Patients unable to perform active movements can benefit from paradigms with passive motor and sensory stimulation. Therefore, we recommend these paradigms for functional somatotopic mapping of the central region at 3T in clinical routine. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

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.     

fMRI activation mapping as a percentage of local excitation: Consistent presurgical motor maps without threshold adjustment

Purpose

To evaluate the performance of a relative activation amplitude algorithm, versus standard t‐value thresholding, for reliably establishing the location, amplitude, and spatial extent of functional magnetic resonance imaging (fMRI) brain activation for presurgical planning.

Materials and Methods

Diagnostic fMRI maps from 42 neurosurgical patients performing a simple hand movement task were analyzed. Relative activation maps were made by normalizing statistical t‐value maps to the local peak activation amplitude within each functional brain region. The spatial distribution of activation was quantified and compared across mapping algorithms, subjects, and scan duration.

Results

Whereas the spatial distribution of blood oxygenation level‐dependent (BOLD) t‐value statistical activation maps was highly variable across subjects and scan duration, the spatial distribution of relative activation maps was highly reproducible both within individual subjects and across different subjects. In every case the 40% most active voxels in the cortical hand region were consistently localized to the pre‐ and postcentral gyri of the sensorimotor cortex.

Conclusion

The reproducibility and anatomical specificity of the spatiotemporal pattern of BOLD activation makes relative amplitude fMRI mapping a useful tool for clinical imaging, where accuracy, reproducibility, and quality control are critical concerns. J. Magn. Reson. Imaging 2009;29:751–759. © 2009 Wiley‐Liss, Inc.     

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。