Mechanisms Altering Electrical Conductivity & DTI in Epilepsy Surgery Patients

改变电导率的机制

基本信息

批准号：
7788906
负责人：
GARY W. MATHERN
金额：
$ 23.1万
依托单位：
UNIVERSITY OF CALIFORNIA LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-01-15 至 2011-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7788906
关键词：
Affect Animal Model Animals Anisotropy Brain Cerebral cortex Cessation of life Data Diffuse Diffusion Magnetic Resonance Imaging Drug Controls Electric Conductivity Electrodes Electroencephalography Epilepsy Etiology Evaluation Glial Fibrillary Acidic Protein Gliosis Goals Gold Grant Individual Lead Lesion MRI Scans Magnetic Resonance Imaging Measurement Measures Mental Retardation Methods Modeling Morbidity - disease rate Myelin Myelin Basic Proteins Operative Surgical Procedures Pathology Patients Proteins Proteolipids Public Health Refractory Research Technics Risk Scalp structure Scanning Seizures Signal Transduction Site Source Structure Surface Techniques Tissues Water Work brain tissue gray matter improved in vivo mortality nervous system disorder neurosurgery public health relevance research study therapy resistant tool water diffusion white matter

项目摘要

DESCRIPTION (provided by applicant): Epilepsy is a frequent neurological disorder, and 25% to 30% have therapy-resistant epilepsy. Of those with uncontrolled epilepsy, some may be candidates for epilepsy neurosurgery if the EEG can be localized to a single site. Scalp EEG has limitations with regard to source localization because of spatial non-uniformity of the brain's electrical conductivity. The goals of this project are to improve our understanding of the brain micro-structure that effect EEG source localization by integrating different research techniques in epilepsy surgery patients. In Preliminary Studies, we demonstrate that cortical electrical conductivities are directionally specific and depend on the type of pathology. Also, there is a relationship between measures of brain electrical conductivity and brain water diffusivity measured by Diffusion Tensor Imaging (DTI) MRI. These findings support our goal of measuring brain electrical conductivity and DTI, and relating these to altered brain structure as steps toward improving methods of EEG source localization. We will accomplish our goals by: 1) Measuring the electrical conductivity of cortical gray matter and subcortical white matter parallel and perpendicular to the pial surface; 2) validate that ex vivo measures of brain electrical conductivity replicate in vivo conditions by performing in vivo and ex vivo experiments in animal models of normal and abnormal brains; 3) use presurgical DTI to determine the water diffusion tensor and the associated principal diffusivities (eigenvalues), principal directions (eigenvectors) and FA from the gyri and cortical sites on which the electrical conductivity measures are performed; 3) determine histopathologic measures of cortical disorganization in sites adjacent to those used for the electrical conductivity and DTI measurements; and 4) model EEG interictal discharges from scalp EEG and MEG/MSI using models that incorporate measures of isotrophic brain from electrical conductivity and DTI and determine if these new methods more closely determine EEG sources as determined by ECoG. The results of these experiments will provide the necessary Preliminary data for an R01 application to develop methods of intracranial EEG source localization that will be individual patients. PUBLIC HEALTH RELEVANCE: One-third of epilepsy patients have seizures that are not controlled by drugs, and are at risk for seizure- induced death and mental retardation. Surgery is an option to treat uncontrolled seizures, but less than half are candidates because of limitations of EEG and MRI techniques. This grant will improve these tools by studying if electrical signals move through the brain differently in epilepsy patients, whether electrical signal changes can be estimated using new MRI techniques, and if the electrical and MRI changes are from disorganization of the cerebral cortex.

描述（由申请人提供）：癫痫是一种常见的神经系统疾病，25% 至 30% 患有难治性癫痫。在那些癫痫不受控制的患者中，如果脑电图可以定位到单个部位，那么有些人可能适合进行癫痫神经外科手术。由于大脑电导率的空间不均匀性，头皮脑电图在源定位方面存在局限性。该项目的目标是通过整合癫痫手术患者的不同研究技术，提高我们对影响脑电图源定位的大脑微结构的理解。在初步研究中，我们证明皮质电导率具有方向特异性，并且取决于病理类型。此外，脑电导率测量值与扩散张量成像 (DTI) MRI 测量的脑水扩散率之间也存在相关性。这些发现支持我们测量脑电导率和 DTI 的目标，并将其与改变的大脑结构联系起来，作为改进 EEG 源定位方法的步骤。我们将通过以下方式实现我们的目标： 1）测量平行和垂直于软脑膜表面的皮质灰质和皮质下白质的电导率； 2) 通过在正常和异常大脑的动物模型中进行体内和离体实验，验证脑电导率的离体测量可在体内条件下复制； 3) 使用术前 DTI 来确定进行电导率测量的脑回和皮质部位的水扩散张量以及相关的主扩散率（特征值）、主方向（特征向量）和 FA； 3) 确定与用于电导率和 DTI 测量的部位相邻的部位的皮质紊乱的组织病理学测量； 4) 使用结合电导率和 DTI 测量各向同性大脑的模型，对来自头皮 EEG 和 MEG/MSI 的 EEG 发作间期放电进行建模，并确定这些新方法是否更准确地确定 ECoG 确定的 EEG 来源。这些实验的结果将为 R01 应用提供必要的初步数据，以开发针对个体患者的颅内 EEG 源定位方法。公共卫生相关性：三分之一的癫痫患者的癫痫发作无法通过药物控制，并且存在癫痫引起的死亡和智力低下的风险。手术是治疗失控癫痫发作的一种选择，但由于脑电图和核磁共振技术的限制，只有不到一半的人愿意手术。这笔赠款将通过研究电信号在癫痫患者大脑中的移动是否不同、电信号变化是否可以使用新的 MRI 技术来估计、以及电信号和 MRI 变化是否来自大脑皮层的紊乱来改进这些工具。