Developing optimized fMRI protocol for clinical use: comparison of different language paradigms

Purpose:

To compare the potential of five functional magnetic resonance imaging (fMRI) language paradigms in activating language areas in Persian‐speaking volunteers in order to optimize these tasks for clinically useful protocol.

Materials and Methods:

16 healthy right‐handed Persian‐speaking volunteers were studied. Each individual performed five tasks during the fMRI scan: word generation (WG), object naming (ON), word reading (WR), word production (WP), and reverse word reading (RWR). The ability of each task to activate classical language areas was assessed using group analysis. In addition, the lateralization index (LI) for each subject‐task was calculated and compared.

Results:

We found that WP, RWR, and WG robustly activated language‐related areas in the dominant hemisphere. ON and WR failed to sufficiently delineate these activation areas. Highest activation intensities in the frontal lobe (including Broca's area) were seen with WP, whereas RWR showed the highest LI among all examined tasks.

Conclusion:

Our results demonstrated that the Persian version of WG and newly presented WP and RWR tasks can be reliably used for localization of language‐related areas in Persian speakers. This type of language evaluation may be used in presurgical planning of neurosurgical procedures in the Persian population. We recommend application of WP and RWR in future researches establishing the optimized protocol for other language speakers. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Developing a comprehensive presurgical functional MRI protocol for patients with intractable temporal lobe epilepsy: a pilot study

Our aim was to put together and test a comprehensive functional MRI (fMRI) protocol which could compete with the intracarotid amytal (IAT) or Wada test for the localisation of language and memory function in patients with intractable temporal lobe epilepsy. The protocol was designed to be performed in under 1 h on a standard 1.5 tesla imager. We used five paradigms to test nine healthy right-handed subjects: complex scene-encoding, picture-naming, reading, word-generation and semantic-decision tasks. The combination of these tasks generated two activation maps related to memory in the mesial temporal lobes, and three language-related maps of activation in a major part of the known language network. The functional maps from the encoding and naming tasks showed typical and symmetrical posterior mesial temporal lobe activation related to memory in all subjects. Only four of nine subjects also showed symmetrical anterior hippocampal activation. Language lateralisation was best with the word generation and reading paradigms and proved possible in all subjects. The reading paradigm enables localisation of language function in the left anterior temporal pole and middle temporal gyrus, areas typically resected during epilepsy surgery. The combined results of this comprehensive f MRI protocol are adequate for a comparative study with the IAT in patients with epilepsy being assessed for surgery.     

fMRI for preoperative neurosurgical mapping of motor cortex and language in a clinical setting

PURPOSE: Identification of the precentral gyrus can be difficult in patients with brain tumors. The purpose of the current study was to evaluate the clinical usefulness of functional MRI (fMRI) in identifying motor cortex and speech areas as a part of preoperative neurosurgical planning. METHOD: fMRI was performed using a 1.5 T MR unit in 41 patients with brain tumors. The motor paradigm was finger tapping and foot movement, whereas the language paradigm consisted of a two word semantic test. Statistical analysis of the data was done using the Kolmogorow-Smirnow test. Plots of signal intensities over time were created. RESULTS: The precentral gyrus was identified in 38 of 41 patients. In two patients, fMRI was not of acceptable quality due to motion artifacts. Speech areas were localized in 33 patients. In a typical clinical setting, the value of the method was graded "high." CONCLUSION: fMRI's efficacy in the preoperative localization of language and motor areas is high. The method should become a routine adjunct for preoperative evaluation of brain tumors in the near future.     

多语种者脑语言活动区的功能磁共振成像研究

目的利用血氧水平依赖性功能磁共振成像(BOLD-fMRI)探讨维吾尔族维-汉-英多语者接受三种语言刺激任务时,大脑语言功能区激活的异同。资料与方法 20名健康维吾尔族维-汉-英多语者行fMRI检查,受试者均在3～5岁开始学习汉语,汉语通过中国高等汉语水平考试汉八级(HSK)。开始学习英语的年龄在10～12岁之间,英语水平全部通过国家大学英语4～6级考试。BOLD-fMRI检查采用组块设计,受试者分别接受维语、汉语及英语认知任务的视觉刺激并进行默读,所得图像数据经SPM5脑功能处理软件处理,生成脑激活图并进行分析,组间数据采用多样本的方差分析。结果三种语言共同激活了双侧额中回和额下回(BA 9、BA 46、47)、左侧颞中回(BA 18)、双侧中央前回(BA 4)、双侧梭状回(BA 37)、左侧顶上下小叶(BA 7/40)、双侧枕中回(BA 19)。不同语言任务时右侧颞上回、颞中回(BA 18、BA 38),左侧楔前叶(BA 19),右侧舌回(BA 18)、右侧顶上下小叶(BA 7/40)、双侧的额内侧回、左侧海马旁回、基底节区(豆状核、尾状核)及小脑扁桃体有散在激活。汉语及英语刺激任务时各脑叶激活强度大于维语,三者间有统计学差异。三种语言任务的优势半球均为左侧大脑半球。结论维吾尔族多语者给予母语、汉语和英语刺激时,三种语言有共同的脑激活区,处理汉语及英语刺激任务时脑激活区激活强度及范围大于母语,三种语言刺激时大脑的偏侧化程度无差异。     

Neuroimaging of language processes: fMRI of silent and overt lexical processing and the promise of multiple process imaging in single brain studies.

OBJECTIVE: To implement and evaluate a multiple-process functional magnetic resonance imaging (fMRI) paradigm designed to effectively and efficiently activate several language-related regions for use with neurosurgical patients. Both overt and covert response conditions were examined. METHODS: The fMRI experiments compared the traditional silent word-generation condition versus an overt one as they engage frontal language regions (Experiment 1) and silent versus overt semantic association conditions as they engage multiple language processing regions (Experiment 2). RESULTS: In Experiment 1, the overt condition yielded greater magnitude of activation, but not volume of activation, in the left inferior frontal and insular cortices than did the silent condition for most, but not all, participants. Experiment 2 demonstrated that the activation of multiple established language processing regions (ie, orthographic, phonological, and semantic) can be achieved in a significant number of participants, particularly under overt semantic association conditions and that such activation varies in predictable ways. CONCLUSION: The traditional silent response condition cannot be considered as equivalent to the overt response condition during word generation or semantic association. The multiple-process imaging method introduced here was sensitive to processing robust orthographic, phonological, and semantic regions, particularly under the overt response condition.     

Localizing and lateralizing language in patients with brain tumors: feasibility of routine preoperative functional MR imaging in 81 consecutive patients

PURPOSE: To prospectively assess the feasibility of standardized presurgical functional magnetic resonance (MR) imaging for localizing the Broca and Wernicke areas and for lateralizing language function. MATERIALS AND METHODS: The study was approved by the responsible ethics commission, and patients gave written informed consent. Eighty-one patients (36 female and 45 male patients; age range, 7-75 years) with different brain tumors underwent blood oxygen level-dependent functional MR imaging at 1.5 T with two paradigms: sentence generation (SG) and word generation (WG). Functional MR imaging measurements, data processing, and evaluation were fully standardized by using dedicated software. Four regions of interest were evaluated in each patient: the Broca and Wernicke areas and their anatomic homologues in the right hemisphere. Statistics were calculated. RESULTS: The SG and WG paradigms were successfully completed by all (100%) and 70 (86%) patients, respectively. Success rates in localizing and lateralizing language were 96% for the Broca and Wernicke areas with the SG paradigm, 81% for the Broca area and 80% for the Wernicke area with the WG paradigm, and 98% for both areas when the SG and WG paradigms were used in combination. Functional localizations were consistent for SG and WG paradigms in the inferior frontal gyrus (Broca area) and the superior temporal, supramarginal, and angular gyri (Wernicke area). Surgery was not performed in seven patients (9%) and was modified in two patients (2%) because of functional MR imaging findings. CONCLUSION: Functional MR imaging proved to be feasible during routine diagnostic neuroimaging for localizing and lateralizing language function preoperatively.     

Intrasubject reproducibility of functional MR imaging activation in language tasks

BACKGROUND AND PURPOSE: The purpose of this study was to examine the reproducibility of functional MR imaging (fMRI) activation (volume and laterality) within both inferior frontal and temporoparietal regions of interest for both receptive and expressive language tasks. METHODS: Ten healthy volunteers participated in fMRI experiments for 6 language tasks: verb generation, confrontation naming, semantic decision making, visual sentence comprehension, auditory sentence comprehension, and story listening. Each subject was scanned during 2 separate sessions separated by a minimum of 4 weeks. Laterality of activation was defined by laterality indices (LIs), which were calculated by 2 methods: one method based on the measured volume of activation and the other method based on the F statistic of the activation. Reproducibility was calculated by using concurrence ratios for the volume of activation (R(overlap), R(volume)) and test-retest correlation for LIs. RESULTS: All tasks generated reproducible LIs within at least one of the regions of interest, but verb generation produced the highest test-retest correlations (r = 0.99) within both regions of interest. Verb generation was associated with the highest average concurrence ratios within the inferior frontal region of interest (R(overlap) = 45.2; R(volume) = 70.9). In general, the concurrence ratios were lower within the temporoparietal region of interest compared with the inferior frontal region of interest. LIs calculated with F statistics were more reproducible than the LIs calculated by activation volume. CONCLUSION: fMRI is able to provide reproducible LIs in both inferior frontal and temporoparietal regions for assessing hemispheric dominance in language processing. The volume of activation, especially within the temporoparietal regions, is less reproducible than the laterality of activation, so the former should be used with caution.     

蒙汉双语者与单汉语者语义加工差异脑机制的功能磁共振成像研究

目的 通过熟练蒙汉双语者及单汉语志愿者的语言功能磁共振成像,探讨蒙汉双语者及汉语志愿者在汉语语义判断过程中汉语信息加工差异的脑机制.方法 采用汉语词的语义判断任务,15名蒙汉双语健康志愿者（男8名,女7名）和15名汉语健康志愿者（男7名,女8名）进行功能磁共振成像研究.应用软件包AFNI分析两种语言任务的脑功能激活情况及其差异.结果 熟练蒙汉双语者及单汉语志愿者在汉语语义信息加工过程中,均激活语义信息加工的经典脑区,包括左侧颞中回后部、左侧顶下小叶、左侧额下回三角部、双侧辅助运动区等区域.比较蒙汉双语者与汉语者在加工汉语的语义信息过程的差异,发现蒙汉双语者主要在双侧枕叶、扣带回后部、左侧颞上回和颞中回后部的激活显著比单汉语者的增加,而在双侧基底节、右侧舌回、左侧额下回眶部,表现比单汉语者的激活更弱.结论 蒙汉双语者加工第二语言存在特殊性,功能磁共振成像研究能够为双语者的语言加工脑机制提供影像学依据.     

数字计算相关脑功能区偏侧化现象fMRI研究

目的 采用磁共振功能成像（fMRI）技术观察计算相关脑功能区的偏侧化现象,判断功能区偏侧化现象与利手因素及数字任务类型之间的关系,并对其原因进行初步分析。资料与方法 对7名左利手和25名右利手志愿者进行简单计算、复杂计算和数字位置判断实验。应用组块设计模式,采用GE 1．5T磁共振扫描仪,对所有志愿者行T1WI和fMRI。采用SPM99软件进行数据分析和脑功能区定位,记录各脑区激活像素数,计算偏侧化指数（LI）,利用LI评价脑功能区的偏侧化现象。结果两组志愿者在执行三种任务时额叶功能区均以利手对侧激活占优势;顶下小叶偏侧化程度较低,但均以左侧激活略明显。在执行简单计算和复杂计算时,右利手组前额皮层、运动前区LI大于左利手组,额下回后部LI小于左利手组,顶下小叶偏侧化程度两组接近。两组中,与简单计算任务相比,执行复杂计算任务时前额皮层、运动前区和顶下小叶的LI均下降,而额下回后部LI增加。结论 fMRI可以检测数字计算相关的脑功能区的偏侧化现象,偏侧化现象与利手因素和任务类型有关。     

Multiple reproducibility indices for evaluation of cognitive functional MR imaging paradigms

BACKGROUND AND PURPOSE: The purpose of this study was to evaluate a variety of reproducibility indices for cognitive functional MR imaging (fMRI) paradigms that account for both overlapping and extraneous regions of activation. METHODS: Eight right-handed volunteers were imaged with fMRI by using a word-generation paradigm and a forward-backward text-listening paradigm. The paradigms were performed twice in the session and repeated 1 week later. Reproducibility indices for the four repeated studies were determined on the basis of pair-wise computation of the ratio of the probability-weighted intersection volume divided by the union volume of surviving activation clusters. The intersection volume was determined by using several iterations of the morphologic dilatation operator with additional voxels accrued in the intersection weighted by an exponential function. Computed indices included global reproducibility, language area reproducibility, extraneous activation reproducibility, and laterality. RESULTS: The word-generation paradigm had reproducibility values that were significantly greater than those of the forward-backward text-listening paradigm (global reproducibility, 0.75 vs 0.5, P <.005; language area reproducibility, 0.85 vs 0.6, P <.008; mean extraneous activation reproducibility, 0.68 vs 0.41, P <.002). The forward-backward text-listening paradigm demonstrated more focal activations, whereas the word-generation demonstrated larger activations outside the dominant language areas that were highly reproducible. CONCLUSION: For clinically relevant language paradigms, multiple reproducibility indices should be taken into account in selecting an appropriate paradigm. Compared with a forward-backward text-listening task, a word-generation task has higher reproducibility indices at the expense of localizing ability. The forward-backward paradigm demonstrates more focal activations with less extraneous activation.     

维吾尔族人汉字语义联想任务的功能MRI研究

目的 运用fMRI探讨以汉语为第二语言的维吾尔族人,对汉字进行阅读联想时,与汉族人大脑激活区域的差异.方法 选取21名健康维吾尔族人与11名健康汉族人进行fMRI.fMRI采用BOLD组块设计,受试者接受单个汉字任务视觉刺激,所得原始图像数据经统计参数图(SPM)5脑功能MR图像处理软件包处理,生成受试者的脑激活图,并进行对照研究,分析维吾尔族人和汉族人脑激活空间分布上的差异.结果 维吾尔族人与汉族人汉字任务主要激活了左侧额中回和额下回(BA 9、47)、颞中回(BA 37)皮层、顶上下小叶(BA 7、40),双侧视觉系统(Bas 17～19)及小脑,两个民族受试者激活区域基本一致,但维吾尔族人的脑激活范围明显大于汉族人.结论 母语为维吾尔语者,其汉字脑处理过程与汉族人激活区域基本一致,但需要更多的脑区来参与和完成;其脑激活范围明显大于汉族人.     

Functional MR imaging study of language-related differences in bilingual cerebellar activation

BACKGROUND AND PURPOSE: Reports in the monolingual literature suggest that the cerebellum has an important role in language processing. The purpose of this study was to determine whether bilingual cerebellar functional MR imaging (fMRI) activation differs during the performance of comparable tasks in subjects' primary and secondary languages. METHODS: Eight bilingual, right-handed individuals underwent echo-planar fMRI at 1.5 T. They performed semantic (noun-verb association) and phonological (rhyming) tasks in Spanish (primary language) and English (secondary language). Individual and group functional datasets were analyzed using Statistical Parametric Mapping software (SPM99; P <.001 with a 10-voxel spatial extent threshold) and overlaid on T1-weighted anatomic images normalized to a standard (Montreal Neurologic Institute) space. Analysis of variance was performed on laterality indices derived from voxel counts in cerebellar regions of interest (ROIs). Subtraction of group-averaged normalized results from the combined Spanish tasks from the combined English tasks was also performed within SPM99 (P <.001 activation threshold). RESULTS: Significantly greater lateralilty indices were noted in the English tasks than in the Spanish tasks (mean Spanish LI, 0.3286; mean English LI, 0.5141 [P =.0143]). Overall, more robust activation was seen in the English tasks than in the Spanish tasks. Areas of significantly greater activation existed in the English tasks as compared with the Spanish tasks; these areas were more prominent in the left cerebellar hemisphere. CONCLUSION: Although both English and Spanish language tasks demonstrate left cerebellar dominance, English tasks demonstrate greater left hemispheric lateralization.     

Functional MRI in symptomatic proliferative angiopathies

Seizures, the main expression of cerebral arteriovenous malformations (AVMs) can be difficult to control medically. We studied fMRI in correlation with clinical findings cerebral activation clusters patterns in relation with singular AVMs (proliferative angiopathy). We carried out blood oxygen-level dependent functional MRI (fMRI) in seven patients with language problems due to capillary ectasia with verbal fluency and repetition language tasks in box-car paradigms. fMRI maps were calculated with cross-correlation coefficients and superimposed on brain anatomy. Five patients had perimalformative and/or contralateral areas of ipsi- and contralateral activation clusters redistribution. One patient who underwent fMRI after a severe focal post-ictal deficit had total hemisphere contralateral activation clusters redistribution.     

用近红外功能成像技术研究语义和知觉编码过程中左前额叶的活动

目的用近红外光学功能成像技术研究语义与知觉编码过程中的左前额叶活动.方法实时记录22名青年被试者(男女各半)在语义和知觉加工过程中760 nm和850 nm两个波长近红外连续光透过额骨和左前额皮层后的漫射光强变化,并以此表征该皮层区血容(CBV)和血氧的变化.语义加工要求被试者用两个非相关的汉字词对组成一个有意义的句子;知觉加工则要求被试者判断两个词是否具有相同的结构组合以及两个词对中左右结构的差别. 结果结果显示,与知觉加工相比,语义加工时左下前额叶活动增多.该区域大致对应布德曼45、47区的一部分. 结论成功地利用近红外功能成像技术观测了语义与知觉编码过程中的左前额叶活动,获得了与fMRI和断层成象技术(PET)研究相近的结果,进一步证实了左前额叶在语义加工中的作用.     

Mapping the functional anatomy of sentence comprehension and application to presurgical evaluation of patients with brain tumor

BACKGROUND AND PURPOSE: The main clinical indication for functional MR imaging (fMRI) has been to preoperatively map the cortex. Motor paradigms to activate the cortex are simple and robust; however, language tasks show greater variability and difficulty. The aim of this study was to develop a language task with an adequate control task to engage the areas of the posterior temporal lobe responsible for sentence comprehension. METHODS: We performed a cloze paradigm requiring silent reading of a visually presented sentence-completion task based on semantic meaning versus a letter-scanning epoch requiring the completion of nonlinguistic strings or a rest period. Before this task was clinically used in two patients epilepsy and cavernous angioma, its feasibility and accuracy were tested in 14 healthy right-handed participants. RESULTS: Results showed significant activation of the posterior temporal cortex, including a broad area across the posterior left temporal cortex extending into the inferior parietal lobule. When the sentence completion-minus-letter string task was compared with the sentence completion-minus-rest task, increased activation was present in the posterior temporal lobe. CONCLUSION: Decreased significant activation during the sentence completion-minus-rest contrast may be attributed to increased noise from intersubject variability in the rest period. Our results suggest that this task elucidates areas important to reading comprehension in the posterior and inferior temporal regions that verbal fluency and auditory discrimination tasks do not. Data from two cases are summarized to exemplify the input of this task for neurosurgery.     

Resting-State Seed-Based Analysis: An Alternative to Task-Based Language fMRI and Its Laterality Index

BACKGROUND AND PURPOSE:Language is a cardinal function that makes human unique. Preservation of language function poses a great challenge for surgeons during resection. The aim of the study was to assess the efficacy of resting-state fMRI in the lateralization of language function in healthy subjects to permit its further testing in patients who are unable to perform task-based fMRI.MATERIALS AND METHODS:Eighteen healthy right-handed volunteers were prospectively evaluated with resting-state fMRI and task-based fMRI to assess language networks. The laterality indices of Broca and Wernicke areas were calculated by using task-based fMRI via a voxel-value approach. We adopted seed-based resting-state fMRI connectivity analysis together with parameters such as amplitude of low-frequency fluctuation and fractional amplitude of low-frequency fluctuation (fALFF). Resting-state fMRI connectivity maps for language networks were obtained from Broca and Wernicke areas in both hemispheres. We performed correlation analysis between the laterality index and the z scores of functional connectivity, amplitude of low-frequency fluctuation, and fALFF.RESULTS:Pearson correlation analysis between signals obtained from the z score of fALFF and the laterality index yielded a correlation coefficient of 0.849 (P < .05). Regression analysis of the fALFF with the laterality index yielded an R² value of 0.721, indicating that 72.1% of the variance in the laterality index of task-based fMRI could be predicted from the fALFF of resting-state fMRI.CONCLUSIONS:The present study demonstrates that fALFF can be used as an alternative to task-based fMRI for assessing language laterality. There was a strong positive correlation between the fALFF of the Broca area of resting-state fMRI with the laterality index of task-based fMRI. Furthermore, we demonstrated the efficacy of fALFF for predicting the laterality of task-based fMRI.

Brain surgery demands preservation of eloquent areas, including the language functional areas. Many studies have illustrated that fMRI is a noninvasive imaging technique that facilitates the lateralization of language function in individual patients.^1–3 The hemispheric language laterality index (LI) is estimated by evaluating the asymmetry in the activation of language areas in the right and left hemispheres of the human brain during a particular task.⁴ The ease of integrating fMRI with other MR imaging techniques allows the correct identification of pathology and its landmark with respect to language areas.^5–7During the acquisition of language fMRI, the subject is instructed to perform particular tasks designed to elicit a response from language functional areas. However, not all subjects, such as those with low intelligence quotients and pediatric patients, will be able to cooperate with the task-based fMRI. Resting-state fMRI (rsfMRI) is gradually evolving as an alternative to task-based fMRI. The rsfMRI technique extracts the low-frequency fluctuations in the blood oxygen level–dependent (BOLD) signal when subjects are instructed to lie relaxed inside the scanner.^7,8Tie et al⁹ extracted language networks from rsfMRI and evaluated the effectiveness of the automatic identification of language components by using independent component analysis. The study separated the activation patterns corresponding to the language network components from individual rsfMRI data. Another study adopted rsfMRI connectivity analysis to examine the degree of hemispheric dominance for language processing in healthy controls and patients with temporal lobe epilepsy.¹⁰ Functional connectivity (FC) analysis of the frontal cortex in the control group revealed a strong correlation with the LI. The authors found a good correlation between the LI and the epileptogenic mesial temporal lobe. Similarly, Pravatà et al¹¹ studied the correlation between the strength of FC between language networks and language performance in healthy controls and patients with epilepsy. They demonstrated an overall reorganization and reduction of the connectivity pattern within the language network of patients with intractable epilepsy. These studies evaluated the FC of language networks rather than regional abnormalities in the low-frequency fluctuations.In rsfMRI, the parameters FC, amplitude of low-frequency fluctuation (ALFF), and fractional amplitude of low-frequency fluctuation (fALFF) are used to examine the network-related and regional characteristics of low-frequency oscillations. FC analysis evaluates the correlation between the time courses of voxels in a seed region with every other region within the brain. The regions with strong correlations will be shown as an FC map.^7,12 ALFF and fALFF are rsfMRI metrics that help in identifying regional BOLD signal changes of rsfMRI fluctuations. ALFF quantifies the amplitude of the low-frequency fluctuations of rsfMRI BOLD signals. fALFF corresponds to the power spectrum of the low-frequency band with respect to all frequencies detectable with the applied time of repetition of the study.^13,14 Different studies reported the clinical application of these metrics.^13,15,16 However, none of the studies considered the accuracy of these metrics in determining the LI.^9–11The objective of our study was to determine the potential of rsfMRI to evaluate language lateralization in comparison with task-based fMRI. In the current study, we evaluated the z scores of FC, ALFF, and fALFF obtained via rsfMRI and assessed the correlations of each of these metrics with the LI of task-based fMRI from individual seed regions. We hypothesized that the metrics of seed-based rsfMRI analysis are strongly correlated with the LI obtained by using task-based fMRI. If this hypothesis is proved, then rsfMRI can be used instead of task-fMRI in patients who cannot perform the task.     

功能MRI对左侧语言相关脑区肿瘤的术前评价

目的 探讨联合应用fMRI及扩散张量纤维束成像对左侧语言相关脑区肿瘤的应用价值.方法 选取15例左侧语言相关脑区肿瘤患者行fMRI及DTI.其中3例患者失语,余患者语言功能轻度受损或正常.功能MR扫描采用视觉呈现、组块设计模式,以及语义相关判断任务.fMRI图像后处理采用个体化分析,在功能激活图与解剖图叠加的图像上测量获得的Broca区和中央前回"手结节"区边缘距离肿瘤边缘最短距离,并计算语言功能偏侧化指数(LI),DTI图像后处理应用Volume-one软件进行纤维束追踪成像,观察额叶白质纤维束,主要是弓状束与肿瘤的位置关系.术前与神经外科医师共同根据脑功能激活图和白质纤维束图显示的肿瘤与功能区和纤维束解剖关系制定手术方案,术后1年进行影像和语言功能随访.结果 语义相关判断任务很好地激活了前、后语言区和中央前回"手结节"运动区.12例患者患侧均可见Broca区、Wernicke区和其他语言处理相关脑区神经网络的激活,并测量Broca区和中央前回"手结节"区距离肿瘤的最短距离,另3例患者因头动明显,数据处理失败.8例患者为左侧语言优势半球,3例患者为右侧语言优势半球,1例患者为双侧语言优势.14例患者纤维柬重建后,3例患者左侧弓状束受浸润破坏,6例受压变形移位,5例完全正常.1例患者DTI图像头动伪影明显,图像处理失败.fMRI和扩散张量纤维束成像成功地帮助神经外科制定个体化手术计划.术后1年随访,1例患者死于并发症,其余患者没有发现肿瘤复发.术前语言功能受损的3例患者,因弓状柬受浸润破坏语言表达能力轻度改善,其余患者语言表达能力明显改善或正常.结论 fMRI及扩散张量纤维束成像联合应用能够更好地观察肿瘤、语言功能区及相关白质纤维束的解剖关系,辅助术前个体化手术方案的制定,最大程度地切除肿瘤,降低了术后语言功能障碍的比例.     

汉字语义加工性别差异的脑功能磁共振成像研究

目的:用功能磁共振成像的方法研究汉字语义加工的脑功能区定位,着重讨论男性和女性语义加工时是否存在性别差异。方法:15例右利手大学生,男7例,女8例,执行汉字同义词判断任务,同时采集其脑部的fMRI数据,采用SPM99进行数据分析,得到相关脑功能区,并对男性和女性语义任务时的脑激活区进行比较。结果:男性激活的脑区包括双侧额下回、左额中回、左颞上回及双侧小脑。女性激活的脑区包括双侧额下回、左额中回、双侧颞上回及双侧小脑。两者脑活动区直接比较,在进行语义任务的时候男性仅激活左侧颞上回,而女性可激活两侧颞上回。结论:男性和女性在进行汉字语义加工任务的时候,两者激活的脑区不完全相同,女性激活的脑区比男性广泛。     

Mapping functionally related regions of brain with functional connectivity MR imaging

BACKGROUND AND PURPOSE: In subjects who are performing no prescribed cognitive task, functional connectivity mapped with MR imaging (fcMRI) shows regions with synchronous fluctuations of cerebral blood flow. When specific tasks are performed, functional MR imaging (fMRI) can map locations in which regional cerebral blood flow increases synchronously with the performance of the task. We tested the hypothesis that fcMRI maps, based on the synchrony of low-frequency blood flow fluctuations, identify brain regions that show activation on fMRI maps of sensorimotor, visual, language, and auditory tasks. METHODS: In four volunteers, task-activation fMRI and functional connectivity (resting-state) fcMRI data were acquired. A small region of interest (in an area that showed maximal task activation) was chosen, and the correlation coefficient of the corresponding resting-state signal with the signal of all other voxels in the resting data set was calculated. The correlation coefficient was decomposed into frequency components and its distribution determined for each fcMRI map. The fcMRI maps were compared with the fMRI maps. RESULTS: For each task, fcMRI maps based on one to four seed voxel(s) produced clusters of voxels in regions of eloquent cortex. For each fMRI map a closely corresponding fcMRI map was obtained. The frequencies that predominated in the cross-correlation coefficients for the functionally related regions were below 0.1 Hz. CONCLUSION: Functionally related brain regions can be identified by means of their synchronous slow fluctuations in signal intensity. Such blood flow synchrony can be detected in sensorimotor areas, expressive and receptive language regions, and the visual cortex by fcMRI. Regions identified by the slow synchronous fluctuations are similar to those activated by motor, language, or visual tasks.