Interface between the meningioma and the brain

Though meningiomas are usually well demarcated from the brain, their interfaces with the brain take various forms. Based on 27 nonoperated supratentorial meningiomas from autopsies, the interfaces were classified into four types, that is, smooth, lobular, finger-like expansion, and invasive. Relationships between the types of interfaces and the so-called capsule of the tumor and subarachnoid vessels are discussed. Additionally, three surgical cases which showed more or less the invasive form are presented with neuroradiological findings.     

Preliminary algorithm for differential diagnosis between spinal meningioma and schwannoma using plain magnetic resonance imaging

Background

Preoperative differential diagnosis between spinal meningioma and schwannoma is critical due to the characteristic differences of the surgical treatments. Thus, we aimed to develop an algorithm for the differential diagnosis of these two lesions based on plain MRI findings.

Diffusion tensor magnetic resonance imaging of brain tumors

DTI seems to offer the possibility of adding important information to presurgical planning. Although experience is limited, DTI seems to provide useful local information about the structures near the tumor, and this seems to be useful in planning. In the future, DTI may provide an improved way to monitor intraoperative surgical procedures as well as their complications. Furthermore, evaluation of the response to treatment with chemotherapy and radiation therapy might also be possible. Although DTI has some limitations, its active investigation and further study are clearly warranted.     

Quantitative magnetic resonance imaging in traumatic brain injury

Quantitative neuroimaging has now become a well-established method for analyzing magnetic resonance imaging in traumatic brain injury (TBI). A general review of studies that have examined quantitative changes following TBI is presented. The consensus of quantitative neuroimaging studies is that most brain structures demonstrate changes in volume or surface area after injury. The patterns of atrophy are consistent with the generalized nature of brain injury and diffuse axonal injury. Various clinical caveats are provided including how quantitative neuroimaging findings can be used clinically and in predicting rehabilitation outcome. The future of quantitative neuroimaging also is discussed.     

Gadolinium — DTPA in magnetic resonance imaging of the brain

This report concerns a clinical trial with Gd-DTPA as an intravenous contrast medium for MRI in patients with neurological disorders. 50 patients (30 female, 20 male) were examined without and with Gd-DTPA and the results of CT scanning and MR scanning without and with Gd-DTPA were compared. All patients tolerated the contrast medium very well. In the various patient groups, Gd-DTPA often added to the information. This was especially true in the tumor group, where better delineation of tumor, blood, and edema was obtained.     

Prediction of meningioma consistency using fractional anisotropy value measured by magnetic resonance imaging

OBJECT: Preoperative planning for meningiomas requires information about tumor consistency as well as location and size. In the present study the authors aimed to determine whether the fractional anisotropy (FA) value calculated on the basis of preoperative magnetic resonance (MR) diffusion tensor (DT) imaging could predict meningioma consistency. METHODS: In 29 patients with intracranial meningiomas, MR DT imaging was performed preoperatively, and the FA values of the tumors were calculated. Tumor consistency was intraoperatively determined as hard or soft, and the histological diagnosis of the tumor was established. RESULTS: Of the 29 tumors, 11 were classified as hard and 18 as soft. The FA values of fibroblastic meningiomas were significantly higher than those of meningothelial meningiomas (p = 0.002). The FA values of hard tumors were significantly higher than those of soft tumors (p = 0.0003). Logistic regression analysis demonstrated that the FA value was a significant independent predictor of tumor consistency (p = 0.007). CONCLUSIONS: The FA value calculated from preoperative MR DT imaging predicts meningioma consistency.     

前庭功能的静息态脑功能磁共振成像

目的探讨基于局部一致性(ReHo)、低频振幅(ALFF)和低频振幅分数(fALFF)的静息态脑fMRI技术对于前庭冰水刺激诱导后脑内前庭功能相关区域的BOLD信号变化。方法纳入20名正常志愿者,在10s内将15ml 0℃冰水注入受试者右侧外耳道,采用平面回波序列和32通道头线圈采集受试者的BOLD静息态脑功能成像数据,采用MatLab 7.1和SPM 8进行数据预处理,预处理后的数据采用REST 1.4软件计算获得ReHo、ALFF和fALFF图像。结果ReHo、ALFF和fALFF图像均出现多个脑区激活增加或减低,其中3个参数值增加即激活脑区主要包括岛叶皮层、颞上回、顶下小叶、脑干、海马旁回、小脑半球等,减低即负激活脑区主要包括额上回、额中回、额下回、颞中回、枕下回、楔前叶等。结论人类存在广泛的涉及前庭信息处理的脑皮层及皮层下网络区域,静息态脑功能成像ReHo、ALFF、fALFF分析方法具有较好的一致性,具备定位前庭功能区的潜在能力。     

Proton magnetic resonance spectroscopic imaging in brain tumor diagnosis

The current state of standard tumor diagnostics using contrast-enhanced MRI and biopsy is assessed in this review, and the progress of proton magnetic resonance spectroscopy (MRS) over the last 15 years is discussed. We summarize MRS basics and describe a typical magnetic resonance session for noninvasive routine tumor diagnostics at 1.5 T, including two-dimensional magnetic resonance spectroscopic imaging (MRSI). The results that can be obtained from such procedures are illustrated with clinical examples. Attention is turned to cutting-edge methodologic and clinical research at 3 T, with examples using high-resolution or very short echo-time three-dimensional MRSI. The current status and limitations in proton MRSI are discussed, and we look to the potential of faster data collection and even higher field strength.     

Peritumoral brain edema in meningiomas: correlations between magnetic resonance imaging, angiography, and pathology

BACKGROUND: The purpose of this study was to evaluate the radiologic characteristics and pathology related to the formation of peritumoral edema in meningiomas. METHODS: Seventy-nine patients with meningioma were examined by MRI and cerebral angiography. The predictive factors possibly related to peritumoral edema, such as patient age, sex, tumor location, tumor size, peritumoral rim (CSF cleft), shape of tumor margin, signal intensity of tumor in T2WI, pial blood supply, and pathology, were evaluated. We defined the edema-tumor volume ratio as EI and used this index to evaluate peritumoral edema. RESULTS: Male sex (P = .009), tumor size (P = .026), signal intensity of tumor in T2WI (P = .016), atypical and malignant tumor (P = .004), and pial blood supply (P = .001) correlated with peritumoral edema on univariate analyses. However, in multivariate analyses, pial blood supply was statistically significant as a factor for peritumoral edema in meningioma (P = .029). Male sex (P = .067, P < .1) and hyperintensity in T2WI (P = .075, P < .1) might have statistical probability in peritumoral edema. CONCLUSIONS: In our results, male sex, hyperintensity on T2WI, and pial blood supply were associated with peritumoral edema in meningioma that influence the clinical prognosis of patients.     

Concordance between functional magnetic resonance imaging and intraoperative language mapping

Although the correspondence between functional-magnetic resonance imaging (fMRI) representations of the sensorimotor cortex and intraoperative electrophysiology (including somatosensory evoked potential, SSEP, recordings and direct cortical stimulation) has been reported, a similar correspondence between fMRI and intraoperative localization of the language-sensitive cortex is not as well established. The aim of the present study was to evaluate the concordance between fMRI and intraoperative electrophysiology with respect to the localization of the language-sensitive and sensorimotor cortices. We present the results of 21 patients who underwent language and sensorimotor mapping by fMRI and intraoperative electrophysiology including SSEP recordings (n = 21), direct cortical stimulation of motor cortex (n = 15) and direct cortical stimulation of Broca's and Wernicke's area (n = 5). When responses were obtained with both methods, localization of function concurred in all cases. These observations suggest that fMRI represents a reliable preoperative tool for the identification of language-sensitive areas.     

Comparison between neuroimaging classifications and histopathological diagnoses using an international multicenter brain tumor magnetic resonance imaging database

OBJECT: The aim of this study was to estimate the accuracy of routine magnetic resonance (MR) imaging studies in the classification of brain tumors in terms of both cell type and grade of malignancy. METHODS: The authors retrospectively assessed the correlation between neuroimaging classifications and histopathological diagnoses by using multicenter database records from 393 patients with brain tumors. An ontology was devised to establish diagnostic agreement. Each tumor category was compared with the corresponding histopathological diagnoses by dichotomization. Sensitivity, specificity, positive and negative predictive values (PPVs and NPVs, respectively), and the Wilson 95% confidence intervals (CI) for each were calculated. In routine reporting of MR imaging examinations, tumor types and grades were classified with a high specificity (85.2-100%); sensitivity varied, depending on the tumor type and grade, alone or in combination. The recognition of broad diagnostic categories (neuroepithelial or meningeal lesions) was highly sensitive, whereas when both detailed type and grade were considered, sensitivity diverged, being highest in low-grade meningioma (sensitivity 100%, 95% CI 96.2-100.0%) and lowest in high-grade meningioma (sensitivity 0.0%, 95% CI 0.0-65.8%) and low-grade oligodendroglioma (sensitivity 15%, 95% CI 5.2-36.0%). In neuroepithelial tumors, sensitivity was inversely related to the precision in reporting of grade and cellular origin; "glioma" was a frequent neuroimaging classification associated with higher sensitivity in the corresponding category. The PPVs varied among categories, in general being greater than their prevalence in this dataset. The NPV was high in all categories (69.8-100%). CONCLUSIONS: The PPVs and NPVs provided in this study may be used as estimates of posttest probabilities of diagnostic accuracy using MR imaging. This study targets the need for noninvasively increasing sensitivity in categorizing most brain tumor types while retaining high specificity, especially in the differentiation of high- and low-grade glial tumor classes.     

Renal magnetic resonance imaging

PURPOSE OF REVIEW: Current magnetic resonance imaging systems allow the visualization of normal and diseased kidney, with exquisite resolution of renal structures. Dynamic contrast magnetic resonance imaging has the potential, unique among all noninvasive modalities, to differentiate diseases that affect different portions of the vascular-nephron system. This article reviews the most important recently published studies in selected topics chosen because of their clinical relevance or potential for technical developments. RECENT FINDINGS: Magnetic resonance imaging is used increasingly to evaluate renal masses, the prenatal genitourinary system, urinary obstruction and infection, renal vasculature, and the kidneys of transplant donors and recipients. Dynamic contrast magnetic resonance renography based on gadolinium chelated to diethylenetriamine pentaacetic acid, a safe (non-nephrotoxic) paramagnetic agent, emerges as the functional renal imaging modality of choice. Both perfusion and filtration rates can be assessed in individual kidney. SUMMARY: Magnetic resonance imaging has the potential to provide a complete anatomic, physiologic, kidney-specific evaluation. With future advances in automated image analysis methods we can expect functional renal magnetic resonance imaging to play an influential role in management of renal disease.     

丙泊酚梯度镇静下功能核磁共振全脑功能的次序变化

目的不同剂量的丙泊酚在大脑中的作用部位是不同的,本研究拟动态地观察丙泊酚在脑内的作用途径,进一步探索其镇静机制。方法招募健康志愿者12例,男6例,女6例,年龄18～40岁,BMI 20～25 kg/m~2,ASAⅠ级。在未输注丙泊酚状态下进行一次静息态功能核磁共振(RS-fMRI)扫描,然后设定丙泊酚初始效应室浓度(Ce)为0.5μg/ml,稳定5 min后完成一次RS-fMRI扫描。逐渐以0.5μg/ml的增幅递增,每个Ce下均完成一次RS-fMRI扫描,直到Ramsay评分达到6分。在全脑范围内进行局部一致性(ReHo)的对比分析。结果与清醒时比较,Ce 0.5μg/ml时小脑后叶、舌回、枕叶、颞叶等脑区ReHo值明显增加(P0.05),前扣带回、中央前回、额叶等ReHo值明显降低(P0.05)。与Ce 0.5μg/ml时比较,Ce 1.0μg/ml时额叶等脑区ReHo值明显增加(P0.05),小脑后叶、海马旁回等ReHo值明显降低(P0.05)。与Ce 1.0μg/ml时比较,Ce 1.5μg/ml时楔前叶、前扣带回、枕叶等脑区ReHo值明显增加(P0.05),小脑前叶、梭状回、顶叶等ReHo值明显降低(P0.05)。与Ce 1.5μg/ml时比较,Ce 2.0μg/ml时小脑前叶、小脑后叶、颞叶等脑区ReHo值明显增加(P0.05),楔前叶、额叶、顶叶等ReHo值明显降低(P0.05)。结论丙泊酚的作用部位广泛,包含皮层和皮层下中枢,表现为效应脑区分布和局部脑活动强度的动态变化。小脑、扣带回和楔前叶在丙泊酚镇静加深的过程中起关键作用。