Mechanisms Altering Electrical Conductivity & DTI in Epilepsy Surgery Patients

改变电导率的机制

• 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
• 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

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％的癫痫病具有抗治疗性癫痫。在患有不受控制的癫痫病的人中，如果可以将脑电图定位到一个部位，则可能是癫痫神经外科手术的候选者。头皮脑电图在源定位方面存在局限性，这是由于大脑电导率的空间不均匀性。该项目的目标是提高我们对大脑微结构的理解，这些结构通过整合癫痫手术患者的不同研究技术来影响脑电图来源的定位。在初步研究中，我们证明皮质电导率在方向上是特定的，并且取决于病理的类型。同样，通过扩散张量成像（DTI）MRI测量的脑电导率测量与脑水扩散率之间存在关系。这些发现支持我们测量大脑电导率和DTI的目标，并将其与大脑结构改变，以改善脑电图源定位方法的步骤。我们将通过：1）测量皮质灰质和皮质下白质的电导率平行，并垂直于皮层表面； 2）通过在正常和异常大脑的动物模型中进行体内和体内实验，验证大脑电导率的体内测量在体内条件下复制； 3）使用术前DTI来确定从GYRI和皮质位点上进行电导率度量的水扩散张量和相关的主扩散（特征值），主方向（特征向量）和FA。 3）确定与用于电导率和DTI测量值的部位相邻的地质混乱的组织病理学测量； 4）使用模型，使用模型结合了来自电导率和DTI的各向异性大脑测量的模型，模型脑电图中的脑电图排放，并确定这些新方法是否更紧密地确定了ECOG确定的EEG源。这些实验的结果将为R01应用提供必要的初步数据，以开发将是个别患者的颅内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不受药物控制，并且有癫痫发作的死亡和智力低下的风险。手术是治疗不受控制的癫痫发作的一种选择，但由于脑电图和MRI技术的局限性，候选人不到一半。该赠款将通过研究癫痫患者的电信号是否在大脑中移动，是否可以使用新的MRI技术估算电信号变化来改善这些工具，以及电信号的变化以及电气和MRI的变化是否来自大脑皮层的混乱。