White matter

白质
  • 文章类型: Journal Article
    目标:最近,7Tesla(7T)癫痫专责小组公布了对耐药局灶性癫痫患者进行7T磁共振成像(MRI)术前评估的建议.这项研究的目的是在药物耐药性局灶性发作的患者的术前检查中实施和评估该共识方案的实用性和诊断价值/潜在的病变勾画对3TMRI的剩余作用癫痫发作。
    方法:7TMRI方案包括T1加权,T2加权,高分辨率冠状T2加权,流体抑制,流体和白质抑制,和磁敏感加权成像,总持续时间为50分钟。两名神经放射科医生独立评估病变识别的能力,这些已识别病变的检测置信度,与3TMRI相比,7T时的病变边界勾画。
    结果:在41名年龄>12岁的患者中,38个被成功地测量和分析。在7T时,平均检测置信度得分没有显着提高(在3T时,3个中的1.95±0.84与3个中的1.64±1.19,p=0.050)。在50%的癫痫患者中,在7T测量,与3TMRI相比,我们观察到了其他发现.此外,我们发现88%的3个T可见病变患者在7T时的边界勾画得到改善.在19%的3TMR阴性病例中,在7T时检测到新的潜在癫痫性病变。
    结论:诊断结果是有益的,但有19%新的7吨比3吨的发现,不是主要的。我们的评估显示,在四个手术病例中,有两个有新的7T发现,癫痫的结局比ILAE1级差。
    OBJECTIVE: Recently, the 7 Tesla (7 T) Epilepsy Task Force published recommendations for 7 T magnetic resonance imaging (MRI) in patients with pharmaco-resistant focal epilepsy in pre-surgical evaluation. The objective of this study was to implement and evaluate this consensus protocol with respect to both its practicability and its diagnostic value/potential lesion delineation surplus effect over 3 T MRI in the pre-surgical work-up of patients with pharmaco-resistant focal onset epilepsy.
    METHODS: The 7 T MRI protocol consisted of T1-weighted, T2-weighted, high-resolution-coronal T2-weighted, fluid-suppressed, fluid-and-white-matter-suppressed, and susceptibility-weighted imaging, with an overall duration of 50 min. Two neuroradiologists independently evaluated the ability of lesion identification, the detection confidence for these identified lesions, and the lesion border delineation at 7 T compared to 3 T MRI.
    RESULTS: Of 41 recruited patients > 12 years of age, 38 were successfully measured and analyzed. Mean detection confidence scores were non-significantly higher at 7 T (1.95 ± 0.84 out of 3 versus 1.64 ± 1.19 out of 3 at 3 T, p = 0.050). In 50% of epilepsy patients measured at 7 T, additional findings compared to 3 T MRI were observed. Furthermore, we found improved border delineation at 7 T in 88% of patients with 3 T-visible lesions. In 19% of 3 T MR-negative cases a new potential epileptogenic lesion was detected at 7 T.
    CONCLUSIONS: The diagnostic yield was beneficial, but with 19% new 7 T over 3 T findings, not major. Our evaluation revealed epilepsy outcomes worse than ILAE Class 1 in two out of the four operated cases with new 7 T findings.
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  • 文章类型: Review
    背景:我们对脑成像中发现的白质高强度(WMH)的理解存在范式转变。它们曾经被认为是衰老的正常现象,因此,无需进一步调查。然而,现在的证据表明这些病变是大脑和心血管健康不良的标志,预示着中风的风险增加,认知能力下降,抑郁与死亡然而,没有针对全科医生和其他临床医生针对不同临床适应症进行脑部磁共振成像扫描的意外发现WMH的具体管理指南.根据中风神经科医生的文献综述和专家意见,医学和成像专家,和全科医生,我们提出了我们的共识声明,以指导成人中偶然发现的WMH的管理。
    结论:当在脑成像中发现偶然的WMH时:进行详细的病史和检查以筛查神经系统事件。调查潜在的未诊断或治疗不足的心血管危险因素,尤其是高血压和糖尿病。当发现危险因素时,开始强化和个性化的心血管风险管理。通过公认的指南治疗潜在的风险因素,但请注意,在没有替代适应症的情况下,不应将抗血小板和抗凝药物用于偶然的WMH。
    大脑健康的机会。我们认为在脑成像上偶然发现WMH代表了研究常见心血管危险因素和优化大脑健康的机会。这可以由全科医生或内科医生开始和监测,而不会延迟等待门诊神经病学检查。
    There is a paradigm shift in our understanding of white matter hyperintensities (WMH) found on brain imaging. They were once thought to be a normal phenomenon of ageing and, therefore, warranted no further investigation. However, evidence now suggests these lesions are markers of poor brain and cardiovascular health, portending an increased risk of stroke, cognitive decline, depression and death. Nevertheless, no specific guidelines exist for the management of incidentally found WMH for general medical practitioners and other clinicians ordering brain magnetic resonance imaging scans for diverse clinical indications. Informed by a literature review and expert opinion gleaned from stroke neurologists, medical and imaging specialists, and general practitioners, we present our consensus statement to guide the management of incidentally found WMH in adults.
    When incidental WMH are found on brain imaging: Perform a detailed history and examination to screen for neurological events. Investigate for potential undiagnosed or undertreated cardiovascular risk factors, especially hypertension and diabetes mellitus. Commence intensive and individualised cardiovascular risk management when risk factors are uncovered. Treat underlying risk factors via accepted guidelines but note that antiplatelet and anticoagulant medications should not be prescribed for incidental WMH in the absence of an alternative indication.
    A brain health opportunity. We consider the discovery of incidental WMH on brain imaging to represent an opportunity to investigate for common cardiovascular risk factors and to optimise brain health. This can be commenced and monitored by the general practitioner or physician without delay in waiting for an outpatient neurology review.
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  • 文章类型: Clinical Trial Protocol
    背景:脑白质萎缩症“白质消失”(VWM)是一种孤儿疾病,具有神经系统衰退和高死亡率。目前,VWM没有批准的治疗方法,但是在理解病理生理学方面的进展导致了有希望的治疗方法的确定。几种研究性药物正在或即将进入临床试验阶段。VWM的临床试验提出了严峻的挑战,由于VWM具有发作性病程;疾病表型高度异质性,仅在早期发作时才可预测;并且研究能力受到患者人数少的限制。为了应对这些挑战并加速治疗,VWM联盟,一群具有VWM专业知识的学术临床医生,决定开发一个核心协议作为试验的模板,为了改进试验设计并促进控制数据的共享,同时允许对其他试验细节的灵活性。核心协议的总体目标是收集安全性,耐受性,以及用于治疗评估和上市许可的疗效数据。
    方法:要开发核心协议,VWM财团指定了一个委员会,包括VWM联盟的临床医生成员,家庭和病人团体倡导者,和统计专家,临床试验设计和与工业联盟。我们起草了三个针对特定年龄的协议,分层为更同质的患者组,年龄≥18岁,≥6至<18年和<6年。我们选择双盲,随机化,≥6岁患者的安慰剂对照设计;<6岁患者的开放标签非随机自然史对照设计。协议描述了研究人群,年龄特定的终点,纳入和排除标准,学习时间表,样本量测定,和统计方面的考虑。
    结论:核心方案提供了跨试验的共享一致性,启用共享控件池,并减少每次试验所需的患者总数,限制服用安慰剂的患者数量。所有VWM临床试验都建议遵守核心方案。其他试验组成部分,如主要结果的选择,药代动力学,药效学,和生物标志物是灵活的,不受核心协议的约束。每个赞助商都负责他们的审判执行,而控制数据由共享的研究组织处理。该核心协议有利于VWM中并行和连续试验的效率,我们希望加快VWM治疗的时间。
    背景:NA。从科学和伦理的角度来看,强烈建议所有使用该核心方案的介入试验在临床试验登记册中进行登记.
    BACKGROUND: The leukodystrophy \"Vanishing White Matter\" (VWM) is an orphan disease with neurological decline and high mortality. Currently, VWM has no approved treatments, but advances in understanding pathophysiology have led to identification of promising therapies. Several investigational medicinal products are either in or about to enter clinical trial phase. Clinical trials in VWM pose serious challenges, as VWM has an episodic disease course; disease phenotype is highly heterogeneous and predictable only for early onset; and study power is limited by the small patient numbers. To address these challenges and accelerate therapy delivery, the VWM Consortium, a group of academic clinicians with expertise in VWM, decided to develop a core protocol to function as a template for trials, to improve trial design and facilitate sharing of control data, while permitting flexibility regarding other trial details. Overall aims of the core protocol are to collect safety, tolerability, and efficacy data for treatment assessment and marketing authorization.
    METHODS: To develop the core protocol, the VWM Consortium designated a committee, including clinician members of the VWM Consortium, family and patient group advocates, and experts in statistics, clinical trial design and alliancing with industries. We drafted three age-specific protocols, to stratify into more homogeneous patient groups, of ages ≥ 18 years, ≥ 6 to < 18 years and < 6 years. We chose double-blind, randomized, placebo-controlled design for patients aged ≥ 6 years; and open-label non-randomized natural-history-controlled design for patients < 6 years. The protocol describes study populations, age-specific endpoints, inclusion and exclusion criteria, study schedules, sample size determinations, and statistical considerations.
    CONCLUSIONS: The core protocol provides a shared uniformity across trials, enables a pool of shared controls, and reduces the total number of patients necessary per trial, limiting the number of patients on placebo. All VWM clinical trials are suggested to adhere to the core protocol. Other trial components such as choice of primary outcome, pharmacokinetics, pharmacodynamics, and biomarkers are flexible and unconstrained by the core protocol. Each sponsor is responsible for their trial execution, while the control data are handled by a shared research organization. This core protocol benefits the efficiency of parallel and consecutive trials in VWM, and we hope accelerates time to availability of treatments for VWM.
    BACKGROUND: NA. From a scientific and ethical perspective, it is strongly recommended that all interventional trials using this core protocol are registered in a clinical trial register.
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  • 文章类型: Journal Article
    BACKGROUND: Vascular cognitive impairment (VCI) is a heterogeneous entity with multiple aetiologies, all linked to underlying vascular disease. Among these, VCI related to subcortical small vessel disease (SSVD) is emerging as a major homogeneous subtype. Its progressive course raises the need for biomarker identification and/or development for adequate therapeutic interventions to be tested. In order to shed light in the current status on biochemical markers for VCI-SSVD, experts in field reviewed the recent evidence and literature data.
    METHODS: The group conducted a comprehensive search on Medline, PubMed and Embase databases for studies published until 15.01.2017. The proposal on current status of biochemical markers in VCI-SSVD was reviewed by all co-authors and the draft was repeatedly circulated and discussed before it was finalized.
    RESULTS: This review identifies a large number of biochemical markers derived from CSF and blood. There is a considerable overlap of VCI-SSVD clinical symptoms with those of Alzheimer\'s disease (AD). Although most of the published studies are small and their findings remain to be replicated in larger cohorts, several biomarkers have shown promise in separating VCI-SSVD from AD. These promising biomarkers are closely linked to underlying SSVD pathophysiology, namely disruption of blood-CSF and blood-brain barriers (BCB-BBB) and breakdown of white matter myelinated fibres and extracellular matrix, as well as blood and brain inflammation. The leading biomarker candidates are: elevated CSF/blood albumin ratio, which reflects BCB/BBB disruption; altered CSF matrix metalloproteinases, reflecting extracellular matrix breakdown; CSF neurofilment as a marker of axonal damage, and possibly blood inflammatory cytokines and adhesion molecules. The suggested SSVD biomarker deviations contrasts the characteristic CSF profile in AD, i.e. depletion of amyloid beta peptide and increased phosphorylated and total tau.
    CONCLUSIONS: Combining SSVD and AD biomarkers may provide a powerful tool to identify with greater precision appropriate patients for clinical trials of more homogeneous dementia populations. Thereby, biomarkers might promote therapeutic progress not only in VCI-SSVD, but also in AD.
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  • 文章类型: Journal Article
    人类脑图或连接体是当今深入研究的对象。脑科学图解法的优势在于丰富的结构,图论的算法和定义可以应用于人类大脑连接的解剖网络。在这些图表中,顶点对应于灰质的小(1-1.5cm2)区域,两个顶点通过一条边连接,如果基于扩散磁共振成像的工作流程发现了轴突纤维,在大脑白质的那些小灰质区域之间运行。今天,该领域的一个主要问题是发现小灰质区域之间的连接方向。在以前的工作中,我们已经报告了布达佩斯参考Connectome服务器http://connectome的构建。pitgroup.org来自NIHHumanConnectome项目中记录的数据。服务器根据可选择的参数生成版本2中的96个受试者和版本3中的418个受试者的共识脑图。布达佩斯参考Connectome服务器发布后,我们认识到服务器的一个令人惊讶和不可预见的属性。对于k=1,2,...的任何值,服务器可以生成418中至少k个图形中存在的连接的脑图,418.当通过从右到左移动Web服务器上的滑块将k值从k=418更改为1时,当然,越来越多的边出现在共识图中。令人惊讶的观察是,新边缘的外观不是随机的:它类似于生长的灌木。我们将这种现象称为共识连接组动态。我们假设Web服务器中滑块的这种运动可能会从以下意义上复制人脑中连接的发展:所有主题中存在的连接都是最古老的连接,那些只存在于逐渐减少的受试者中的个体大脑发育中的新联系。有关该现象的动画可在https://youtu获得。是/yxlyudPaVUE。基于这一观察和相关假设,我们可以为连接体的某些边缘分配方向,如下所示:令Gk+1表示共识连接体,其中每个边缘至少存在于k+1个图形中,让Gk表示一致性连接体,其中每个边存在于至少k个图中。假设顶点v不连接到Gk+1中的任何其他顶点,并且连接到Gk中的顶点u,其中u连接到已经在Gk+1中的其他顶点。然后我们指导这个(v,u)从v到u的边。
    The human braingraph or the connectome is the object of an intensive research today. The advantage of the graph-approach to brain science is that the rich structures, algorithms and definitions of graph theory can be applied to the anatomical networks of the connections of the human brain. In these graphs, the vertices correspond to the small (1-1.5 cm2) areas of the gray matter, and two vertices are connected by an edge, if a diffusion-MRI based workflow finds fibers of axons, running between those small gray matter areas in the white matter of the brain. One main question of the field today is discovering the directions of the connections between the small gray matter areas. In a previous work we have reported the construction of the Budapest Reference Connectome Server http://connectome.pitgroup.org from the data recorded in the Human Connectome Project of the NIH. The server generates the consensus braingraph of 96 subjects in Version 2, and of 418 subjects in Version 3, according to selectable parameters. After the Budapest Reference Connectome Server had been published, we recognized a surprising and unforeseen property of the server. The server can generate the braingraph of connections that are present in at least k graphs out of the 418, for any value of k = 1, 2, …, 418. When the value of k is changed from k = 418 through 1 by moving a slider at the webserver from right to left, certainly more and more edges appear in the consensus graph. The astonishing observation is that the appearance of the new edges is not random: it is similar to a growing shrub. We refer to this phenomenon as the Consensus Connectome Dynamics. We hypothesize that this movement of the slider in the webserver may copy the development of the connections in the human brain in the following sense: the connections that are present in all subjects are the oldest ones, and those that are present only in a decreasing fraction of the subjects are gradually the newer connections in the individual brain development. An animation on the phenomenon is available at https://youtu.be/yxlyudPaVUE. Based on this observation and the related hypothesis, we can assign directions to some of the edges of the connectome as follows: Let Gk + 1 denote the consensus connectome where each edge is present in at least k+1 graphs, and let Gk denote the consensus connectome where each edge is present in at least k graphs. Suppose that vertex v is not connected to any other vertices in Gk+1, and becomes connected to a vertex u in Gk, where u was connected to other vertices already in Gk+1. Then we direct this (v, u) edge from v to u.
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  • 文章类型: Journal Article
    对于精确的EEG/MEG源分析,有必要尽可能真实地对头部体积导体进行建模。这包括人头部中不同导电隔室的区别。在这项研究中,我们调查了建模/不建模的影响,头骨致密,脑脊液(CSF),灰质,和白质以及在EEG/MEG正解上包含白质各向异性。因此,我们创建了具有白质各向异性的高度逼真的6隔室头部模型,并使用了最先进的有限元方法。从3个隔间的场景开始(皮肤,头骨,和大脑),随后,我们通过区分上述隔室中的另一个来改进我们的头部模型。对于生成的五个头部模型中的每一个,我们测量了与高分辨率参考模型和上一个细化步骤中生成的模型相关的信号形貌和信号幅度的影响。我们使用各种可视化方法评估了这些模拟的结果,让我们获得效果强度的总体概述,触发这些影响的最重要的源参数,以及受影响最大的大脑区域。因此,从三格方法开始,我们确定了头部体积导体建模中最重要的其他细化步骤。我们能够证明包含高导电的CSF隔室,其电导率值众所周知,在两种模态中对信号地形和幅度的影响最强。我们发现灰/白质区别的影响几乎与CSF包涵体一样大,对于这两个步骤,我们都确定了效果空间分布的清晰模式。与这两个步骤相比,白质各向异性的引入导致明显较弱,但仍然坚强,效果。最后,当对均质室使用优化的电导率值时,颅骨海绵状体和致密体之间的区别在两种方式中的作用最弱。我们得出的结论是,在头部体积导体建模中包括CSF并区分灰质和白质是非常值得推荐的。特别是对于MEG,由于影响较弱,颅骨海绵状体和致密体的建模可能会被忽略;考虑到基础建模方法的复杂性和当前局限性,不建模白质各向异性的简化是可以接受的。
    For accurate EEG/MEG source analysis it is necessary to model the head volume conductor as realistic as possible. This includes the distinction of the different conductive compartments in the human head. In this study, we investigated the influence of modeling/not modeling the conductive compartments skull spongiosa, skull compacta, cerebrospinal fluid (CSF), gray matter, and white matter and of the inclusion of white matter anisotropy on the EEG/MEG forward solution. Therefore, we created a highly realistic 6-compartment head model with white matter anisotropy and used a state-of-the-art finite element approach. Starting from a 3-compartment scenario (skin, skull, and brain), we subsequently refined our head model by distinguishing one further of the above-mentioned compartments. For each of the generated five head models, we measured the effect on the signal topography and signal magnitude both in relation to a highly resolved reference model and to the model generated in the previous refinement step. We evaluated the results of these simulations using a variety of visualization methods, allowing us to gain a general overview of effect strength, of the most important source parameters triggering these effects, and of the most affected brain regions. Thereby, starting from the 3-compartment approach, we identified the most important additional refinement steps in head volume conductor modeling. We were able to show that the inclusion of the highly conductive CSF compartment, whose conductivity value is well known, has the strongest influence on both signal topography and magnitude in both modalities. We found the effect of gray/white matter distinction to be nearly as big as that of the CSF inclusion, and for both of these steps we identified a clear pattern in the spatial distribution of effects. In comparison to these two steps, the introduction of white matter anisotropy led to a clearly weaker, but still strong, effect. Finally, the distinction between skull spongiosa and compacta caused the weakest effects in both modalities when using an optimized conductivity value for the homogenized compartment. We conclude that it is highly recommendable to include the CSF and distinguish between gray and white matter in head volume conductor modeling. Especially for the MEG, the modeling of skull spongiosa and compacta might be neglected due to the weak effects; the simplification of not modeling white matter anisotropy is admissible considering the complexity and current limitations of the underlying modeling approach.
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