Preoperative assessment of language areas in epileptic patients using functional MR imaging

ObjectiveTo determine the role of functional magnetic resonance imaging (fMRI) in assessing hemispheric language dominance in patients with epilepsy who are candidates for surgical treatment.Patients and methodsThis study was conducted on (14) consecutively enrolled epileptic patients (12 males, 2 females; mean age, 21 years; range 16–58 years) who were prospectively examined by the neurologist. Eleven (78.6%) patients were dominantly right handed, three (21.4%) were dominantly left handed. All of them underwent language assessment with fMRI and the results were compared with the intraoperative direct electrical stimulation mapping recordings.ResultsIn all the 14 epilepsy cases, language mapping data was concordant between fMRI and intraoperative direct electrocortical stimulation recordings for language dominance. However, fMRI mapping allowed for discrete, focal localization of regions involved in language processes whereas electrical recordings only delineated hemispheric dominance.ConclusionfMRI is considered as a powerful pre-surgical planning tool that has the potential to replace invasive and costly conventional methods. FMRI maps can easily be uploaded and used intra-operatively during stereotactic neurosurgery for accurate localization of complex brain functions.     

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.     

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.     

Identification of the corticospinal tracts achieved using blood-oxygen-level-dependent and diffusion functional MR imaging in patients with brain tumors

Diffusion-weighted MR imaging was used to delineate the corticospinal tract (CST) successfully and to depict its relationship to adjacent brain tumors. The CST was defined by a method by which it seems possible to delimit the distance from the CST to the main tumor mass and to show displacement and infiltration of the tract by the neoplasia. This information cannot be gathered from routine anatomic MR imaging.     

轻度创伤性脑损伤病人的工作记忆:功能MRI分析

摘要目的分析大脑激活模式对轻度创伤性脑损伤(MTBI)后工作记忆检测的反应。材料与方法本研究已获得伦理委员会批准,且入组病人均签署知情同意书。对20例MTBI损伤后1个月之内及18名健康对照者行功能MRI,     

Preoperative functional MR imaging localization of language and motor areas: effect on therapeutic decision making in patients with potentially resectable brain tumors

PURPOSE: To prospectively evaluate the effect of preoperative functional magnetic resonance (MR) imaging localization of language and motor areas on therapeutic decision making in patients with potentially resectable brain tumors. MATERIALS AND METHODS: The Institutional Review Board approved this HIPAA-compliant study, and each patient gave written informed consent. Thirty-nine consecutive patients (19 male, 20 female; mean age, 42.2 years) referred for functional MR imaging for possible tumor resection were prospectively evaluated. A preoperative diagnosis of brain tumor was made in all patients. Sentence completion and bilateral hand squeeze tasks were used to map language and sensory motor areas. Neurosurgeons completed questionnaires regarding the proposed treatment plan before and after functional MR imaging and after surgery. They also gave confidence ratings for functional MR imaging results and estimated the effect on surgical time, extent of resection, and surgical approach. The effect of functional MR imaging on changes in treatment plan was assessed with the Wilcoxon signed rank test. Differences in confidence ratings between altered and unaltered treatment plans were assessed with the Mann-Whitney U test. The estimated influence of functional MR imaging on surgical time, extent of resection, and surgical approach was denoted with summary statistics. RESULTS: Treatment plans before and after functional MR imaging differed in 19 patients (P < .05), with a more aggressive approach recommended after imaging in 18 patients. There were no significant differences in confidence ratings for functional MR imaging between altered and unaltered plans. Functional MR imaging resulted in reduced surgical time (estimated reduction, 15-60 minutes) in 22 patients who underwent surgery, a more aggressive resection in six, and a smaller craniotomy in two. CONCLUSION: Functional MR imaging enables the selection of a more aggressive therapeutic approach than might otherwise be considered because of functional risk. In certain patients, surgical time may be shortened, the extent of resection increased, and craniotomy size decreased.     

肝硬化轻微型肝性脑病病人大脑功能连接的改变:功能性MR成像研究

目的应用功能性MRI探讨轻微型肝性脑病病人的全脑功能连接改变。材料与方法本研究得到单位伦理委员会批准,符合HIPAA原则。所有病人都签署了知情同意书。采用A型数字连接试验和数字符号测试在内的神经心理测试确定轻微型肝性脑病的诊断。选取23例轻微型肝性脑病病人和25名年龄、性别相匹配的健康志愿者纳入此次试验。采用3.0TMR设备进行静息态功能成像。在轻微型肝性脑病病人和正常对照组中,比较90对皮质和皮质下区的功能连接情况,存在显著差异的功能连接作为兴趣连接(COI)。并且将兴趣连接的相关系数与神经心理测试结果进行相关性分析。结果轻微型肝性脑病病人与正常对照组在51个区域(COI)存在统计学差异,其中44个功能连接在肝性脑病时表现为减弱。所有的22个皮质下COI区(双侧壳核、苍白球、丘脑)均表现出功能连接减弱。在29个皮质COI区中,轻微型肝性脑病时22个表现为连接减弱,其余7个表现为连接增强。几乎所有存在差异的兴趣连接均与数字符号测试得分之间存在相关性(P<0.05,错误发现率校正)。轻微型肝性脑病病人的血氨水平、Child-Pugh评分和兴趣连接之间未发现相关性(P>0.05,错误发现率校正)。结论研究发现轻微型肝性脑病病人存在着与神经心理损害相关的广泛的皮质和皮质下功能连接改变。轻微型肝性脑病病人的基底节-丘脑皮质通路障碍可能存在神经认知损害,特别是在精神运动加速和注意力缺陷中扮演着重要角色。     

MR imaging of the brain in patients with mucopolysaccharidosis

MR imaging of the brain was performed in eight patients with mucopolysaccharidosis (MPS). Two had MPS I S, one had MPS IIA, two had MPS IIB, two had MPS IIIB, and one had MPS VI. In the patients with MPS IIA and MPS VI, T1 and T2 were prolonged in various areas of the cerebral white matter. These findings seemed to correspond with the development of pathologic changes in MPS, such as perivascular pits in the white matter observed on slices of the fixed brain. In the patients with MPS IIA and MPS IIIB, the white matter did not show the proper signal intensity, which suggested that myelination was insufficient and that infiltration or deposition of glycosaminoglycan had occurred; this was consistent with the association of these two types with mental retardation. In the patients with MPS I S, no intracranial abnormalities were detected on MR images. MR imaging of the brain may be used to obtain a differential diagnosis of the various types of MPS, to estimate the extent of mental retardation, and to monitor the progress of this disease.     

Lack of sex effect on brain activity during a visuomotor response task: functional MR imaging study

BACKGROUND AND PURPOSE: As more individuals are enrolled in clinical functional MR imaging (fMRI) studies, an understanding of how sex may influence fMRI-measured brain activation is critical. METHODS: We used fixed- and random-effects models to study the influence of sex on fMRI patterns of brain activation during a simple visuomotor reaction time task in the group of 26 age-matched men and women. We evaluated the right visual, left visual, left primary motor, left supplementary motor, and left anterior cingulate areas. RESULTS: Volumes of activations did not significantly differ between the groups in any defined regions. Analysis of variance failed to show any significant correlations between sex and volumes of brain activation in any location studied. Mean percentage signal-intensity changes for all locations were similar between men and women. A two-way t test of brain activation in men and women, performed as a part of random-effects modeling, showed no significant difference at any site. CONCLUSION: Our results suggest that sex seems to have little influence on fMRI brain activation when we compared performance on the simple reaction-time task. The need to control for sex effects is not critical in the analysis of this task with fMRI.     

库欣病患者脑功能改变及任务态功能磁共振成像研究

目的 采用情绪评估量表和任务态功能磁共振成像(Task fMRI)技术,分析库欣病(CD)患者脑功能改变及其与精神症状的关系.方法 收集2015年11月-2016年11月在解放军总医院内分泌科住院诊断为库欣病的8例患者,并选取21名年龄、性别和受教育程度相匹配的健康人作为对照组,对其进行Zung抑郁自评量表(SDS)、Zung焦虑自评量表(SAS)、正性负性情绪量表(PANAS)和库欣生活质量量表(Cushing QOL)的评估,并行Task fMRI检查.结果 与对照组相比,CD组患者均存在抑郁、焦虑状态,正性情绪评分低,而负性情绪评分较高.Task fMRI结果 显示,观看正性图片时CD组左侧小脑和右侧中央后回激活程度较对照组减弱,左侧小脑激活程度与16:00点促肾上腺皮质激素(ACTH)水平呈正相关,右侧中央后回激活程度与尿游离皮质醇(UFC)水平呈正相关;观看负性图片时左侧小脑、双侧海马旁回和左侧额下回激活程度较对照组明显减弱,左侧小脑激活程度与0:00点皮质醇水平和焦虑量表评分呈负相关,与UFC水平呈正相关;观看中性图片时左侧小脑和左侧海马旁回激活程度较对照组减弱.结论 CD患者脑功能受损,会出现抑郁、焦虑等精神障碍,通过Task fMRI技术可发现左侧额下回、右侧中央后回、双侧海马旁回和左侧小脑激活程度减弱与之相关.     

MR imaging of the brain in patients with diabetes insipidus

Diabetes insipidus is a clinical syndrome characterized by the excretion of copious volumes of dilute urine combined with persistent intake of abnormally large quantities of fluid. There are two general forms of the disease, central (vasopressin deficient) and nephrogenic (vasopressin resistant). Diabetes insipidus of central origin most often results from lesions in the hypothalamic-neurohypophyseal axis. Twenty-six cases of central diabetes insipidus were evaluated with the use of high-field-strength MR imaging. A wide variety of precipitating conditions were found, including Langerhans cell histiocytosis, neoplasia, trauma, and infection. A thickened pituitary infundibulum was seen in most patients, and an absence of high intensity signal in the posterior pituitary lobe on T1-weighted images was seen in every case. Analysis of stalk morphology; associated brain findings; and correlation with the patient's age, sex, history, and radiographs of other body parts improved diagnostic specificity. When combined with clinical information, MR imaging is able to provide a specific diagnosis in almost all cases of central diabetes insipidus.     

Gadopentetate dimeglumine-enhanced MR imaging in children following surgery for brain tumor: spectrum of meningeal findings

Gadopentetate dimeglumine-enhanced MR imaging was performed in 51 consecutive postoperative pediatric neurosurgical patients with a diagnosis of brain tumor. These studies were examined retrospectively to determine the spectrum of meningeal findings in this patient population. Patterns of enhancement were correlated with type of surgery, interval since surgery, clinical and CSF findings, and the use of radiation and steroid therapies. Normal postoperative meningeal findings include no meningeal enhancement or mild focal or diffuse dural enhancement. More moderate dural or subdural enhancement may be seen in clinically well children who have postsurgical subdural collections, or who have a remote history of serious meningeal disease (meningitis or subarachnoid hemorrhage). In all six cases in which nodular dural, leptomeningeal, or ependymal enhancement was seen, recurrent local tumor, leptomeningeal metastases, or infection were present. Leptomeningeal tumor or infection should be suspected if such patterns of enhancement are noted. Parameters that did not appear to affect the pattern of meningeal enhancement included type of surgery, interval since surgery, or therapeutic radiation.     

MR imaging of the brain in patients with migraine headaches

Forty-one patients with migraine headaches were referred for MR imaging of the brain. Intermediate and T2-weighted images were obtained to determine the frequency of areas of high intensity within the white matter. The average age of these patients was 29.8 years; only five were over 40 years old. Each patient was evaluated in the axial plane with long TR/short and long TE images. Twenty-three patients also had T1-weighted short TR/short TE MR scans; enhancement with gadopentetate dimeglumine was used in three patients. Intracranial abnormalities were seen in only six patients: foci or white matter high intensity on intermediate and T2-weighted images in five and a venous angioma in one. Prior studies have indicated that parenchymal brain abnormalities may be found in up to 46% of patients with migraines. The current study demonstrated parenchymal brain lesions in only 12%. This study suggests that the frequency of foci of high intensity seen on long TR sequences in the migraine patient is much lower than previously reported, especially in patients under 40 years old (5.5% in our series).     

Assessment of phase and amplitude effects due to susceptibility variations in MR imaging of the brain

Susceptibility effects due to the presence of hemorrhage have been observed in a substantial number of patients and are a potential source of artifact in in vivo spectroscopy. The studies so far have concentrated on observations of phase differences, but amplitude variations also exist. This article reviews the degree to which the two are independent and suggests that at least three different pulse sequences are necessary to characterize effects due to local field inhomogeneities arising in clinical studies.     

Gd-DTPA-enhanced MR imaging of the brain in patients with meningitis: comparison with CT

Plain and Gd-DTPA-enhanced MR images of the brain were obtained in 18 consecutive patients with meningitis (eight with tuberculous, five with bacterial, three with viral, and two with fungal infections); the MR images were compared with CT scans. MR images were obtained on a 2.0-T superconducting unit with both T1- and T2-weighted pulse sequences before injection and with a T1-weighted sequence after injection of Gd-DTPA (0.1 mmol/kg) in all patients. In tuberculous meningitis, MR imaging depicted ischemia/infarct, hemorrhagic infarct of basal ganglia, meningeal enhancement at either basal cistern or convexity surface of brain, and associated small granulomas in a few more patients than CT did. In bacterial meningitis, primary foci of extracranial inflammation (i.e., mastoid, paranasal sinuses) and adjacent intracranial lesions including localized dural inflammation, subdural fluid collection, and/or brain parenchymal lesions were demonstrated much better on MR than on CT. Otherwise, MR images generally matched the CT scan. Although the plain MR images, both T1- and T2-weighted, were the most sensitive in delineating ischemia/infarct, hemorrhage, and edema, they were not as specific as Gd-DTPA-enhanced T1-weighted images and postcontrast CT scans in defining the active inflammatory process of the meninges and focal lesions precisely. We conclude that if Gd-DTPA is used, MR imaging appears to be superior to CT in the evaluation of patients with suspected meningitis. Precontrast MR is needed to delineate ischemia/infarct, edema, and subacute hemorrhage.     

Role of MR imaging in the selection of patients with early cervical carcinoma for fertility-preserving surgery: initial experience.

PURPOSE: To assess whether magnetic resonance (MR) imaging can be used for reliable prediction of proximal extension of cervical carcinoma into the myometrium. MATERIALS AND METHODS: Thirty patients with early cervical carcinoma underwent MR imaging with use of a 1.5-T magnet prior to surgery. The MR images were analyzed by two radiologists, unaware of the histopathologic findings, for the relationship of the tumor to the internal os and extension of the tumor into the myometrium. Findings at MR imaging were compared with those at histopathologic examination. RESULTS: At MR imaging, 24 patients were considered not to have tumor extension proximal to the internal os and into the myometrium. All tumors were confirmed histopathologically. In six patients thought to have myometrial tumor invasion at MR imaging, five tumors were confirmed histopathologically; in one, tumor extended up to the internal os but did not involve the myometrium. CONCLUSION: This is a small study, but MR imaging appears accurate in the prediction of myometrial tumor involvement and in showing the relationship of cervical carcinoma to the internal os and, hence, the patient's suitability for trachelectomy.     

Reproducibility of activations in Broca area with two language tasks: a functional MR imaging study

BACKGROUND AND PURPOSE: Functional MR imaging (fMRI) is rapidly evolving and claims to complement or even substitute intraoperative mapping (IOM) of language functions. However, little is known about the reproducibility of imaging data in the language domain. The aim of our study was to assess the reproducibility of activations for 2 widely used paradigms: naming and word generation. Individual analysis was focused on the Broca area and the left insula. MATERIALS AND METHODS: We examined 13 healthy right-handed subjects in 3 sessions with fMRI. Two conditions were assessed: overt naming and overt naming plus noun generation. The same stimuli were used in all of the sessions. A random-effects analysis was performed to analyze whole-brain activation on a group level. For the regions of interest, the number of voxels classified as active were counted for each subject, and individual reproducibility coefficients were calculated over sessions. RESULTS: For the naming condition, the random-effects analysis did not reveal significant activations in the specified regions; small individual activations were not reproducible. For the combined task, all of the subjects showed activations in the Broca area that were more extensive and reproducible than in the naming task. Activations in the insula were only poorly reproducible. CONCLUSION: Naming is an approved task in IOM but does not identify the Broca area with fMRI in a reproducible way. Priming may have affected our results, but the use of a combined task, in which naming is paired with noun generation, improves the reproducibility of activations and is also suitable for IOM.     

Gd-DTPA-enhanced MR imaging of the brain in patients with meningitis: comparison with CT

Plain and Gd-DTPA-enhanced MR images of the brain were obtained in 18 consecutive patients with meningitis (eight with tuberculous, five with bacterial, three with viral, and two with fungal infections); the MR images were compared with CT scans. MR images were obtained on a 2.0-T superconducting unit with both T1- and T2-weighted pulse sequences before injection and with a T1-weighted sequence after injection of Gd-DTPA (0.1 mmol/kg) in all patients. In tuberculous meningitis, MR imaging depicted ischemia/infarct, hemorrhagic infarct of basal ganglia, meningeal enhancement at either basal cistern or convexity surface of brain, and associated small granulomas in a few more patients than CT did. In bacterial meningitis, primary foci of extracranial inflammation (i.e., mastoid, paranasal sinuses) and adjacent intracranial lesions including localized dural inflammation, subdural fluid collection, and/or brain parenchymal lesions were demonstrated much better on MR than on CT. Otherwise, MR images generally matched the CT scan. Although the plain MR images, both T1- and T2-weighted, were the most sensitive in delineating ischemia/infarct, hemorrhage, and edema, they were not as specific as Gd-DTPA-enhanced T1-weighted images and postcontrast CT scans in defining the active inflammatory process of the meninges and focal lesions precisely. We conclude that if Gd-DTPA is used, MR imaging appears to be superior to CT in the evaluation of patients with suspected meningitis. Precontrast MR is needed to delineate ischemia/infarct, edema, and subacute hemorrhage.