HIGH RESOLUTION T2 WEIGHTED BOLD fMRI IN HUMANS

描述（由申请人提供）：功能性磁共振成像（fMRI）能够监测血管对神经元活动的反应。血管反应，局部血流量，血容量和耗氧量的变化，通过相应的氧合水平的变化来测量。脱氧血红蛋白的顺磁性作为造影剂，用于监测伴随神经活动的血液动力学变化。血氧水平依赖（BOLD）对比度已被广泛使用，并且是脑功能（特别是人类）非侵入性成像的首选方法。随着BOLD fMRI应用于脑功能的高空间分辨率映射，了解血管反应的特异性限制以及如何在使用BOLD fMRI时利用这些特异性限制变得越来越重要。BOLD fMRI可以使用T2或T2'加权图像进行，这两种图像对BOLD效应都有敏感性，尽管不同。我们的长期目标是认识到BOLD信号的局限性，以提高映射人脑中高分辨率功能结构的准确性。所提出的研究的中心假设是T2加权BOLD fMRl可以有效地实现用于人类的高空间分辨率应用，并且在高磁场下最大化BOLD响应的特异性。这一假设已经从大量的初步数据中形成，这些数据表明高分辨率T2加权BOLD fMRI在人类中的可行性，以及预测在高磁场下T2加权BOLD信号的特异性和灵敏度的优势的理论考虑。中心假设将得到检验，申请的目标将通过追求三个具体目标来实现：1）开发用于人脑的高分辨率T2加权成像序列，2）评估T2响应随场强变化时的血管性质，以及3）确定T2加权BOLD fMR 1是否比常规T2 ′加权BOLD fMR 1更适合，用于人体的高空间分辨率应用。所提出的研究的基本原理是：T2加权BOLD fMRI可以提供关于与功能性脑激活相关的微血管和血流动力学变化的更详细和更具体的信息。作为一个先进的MR中心，我们具有独特的优势来开展拟议的研究。我们的实验室在功能成像、先进的硬件和软件开发以及专业的RF线圈设计方面拥有完善的专业知识。所提出的研究是创新的，因为迄今为止在亚毫米分辨率下人脑中的高分辨率T2加权BOLD fMRl还不可行。我们希望T2加权BOLD功能磁共振成像将是高空间分辨率应用的首选成像方法。这是重要的，因为对可靠地映射人脑中的高分辨率功能结构的需求日益增加。它将推动非侵入性脑映射领域对神经元活动的特异性和敏感性达到无与伦比的水平。

DESCRIPTION (provided by applicant): Functional magnetic resonance imaging (fMRI) has the ability to monitor the vascular response to neuronal activity. The vascular response, changes in local blood flow, blood volume and oxygen consumption, is measured by the corresponding changes in oxygenation levels The paramagnetic nature of deoxygenated hemoglobin serves as a contrast agent for monitoring hemodynamic changes accompanying neural activity. Blood oxygen level dependent (BOLD) contrast has been widely utilized and the method of choice for non-invasive imaging of brain function, specifically in humans. With the application of BOLD fMRl to high spatial resolution mapping of brain function, it is becoming increasingly important to understand the specificity limitations of the vascular response and how to exploit these limits of specificity when using BOLD fMRI. BOLD fMRI may be performed using either T2 or T2' weighted images, both of which have sensitivity, although different, to BOLD effects. Our long-range goal is to realize the limitations of BOLD signals for the purpose of increasing the accuracy of mapping high resolution functional structures in the human brain. The central hypothesis of the proposed research is that T2 weighted BOLD fMRl can be efficiently implemented for high spatial resolution applications in humans and at high magnetic fields maximizes the specificity of the BOLD response. This hypothesis has been formdated from a substantial amount of preliminary data, which suggest feasibility of high resolution T2 weighted BOLD fMRl in humans, and theoretical considerations which predict advantages in specificity and sensitivity for T2 weighted BOLD signals at high magnetic fields. The central hypothesis will be tested and the objective of the application will be accomplished by pursuing three specific aims: 1) Develop a high-resolution T2 weighted imaging sequence for use in the human brain, 2) assess the vascular nature of the T2 response as it changes with fields strength, and 3) to determine whether or not T2 weighted BOLD fMRl is more suited, than conventional T2' weighted BOLD fMRl, for high spatial resolution applicants in humans. The rationale for the proposed research is: T2 weighted BOLD fMRl can provide more detailed and more specific information on microvascufar and hemodynamic changes associated with functional brain activation. As an advanced MR center, we are uniquely positioned to undertake the proposed research. Our laboratory has well-established expertise in functional imaging, advanced hardware and software development, and specialized RF coil design. The proposed research is innovative as high resolution T2 weighted BOLD fMRl in the human brain at submillimeter resolutions has not been feasible to date. We expect that T2 weighted BOLD fMRI will be the imaging method of choice for high spatial resolution applications. This is significant because of the increasing demands to reliably map high resolution functional structures in the human brain. It will advance the field of non-invasive brain mapping to unmatched levels of specificity and sensitivity to neuronal activity.