Imaging Brain Activation with Steady-State Free Precession MRI

使用稳态自由进动 MRI 对大脑激活进行成像

• 批准号: 7382796
• 负责人: John M. Pauly
• 金额: $ 32万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-10 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7382796
• 关键词: Age; Area; Biomedical Engineering; Blood; Blood capillaries; Brain; Brain imaging; Cities; Coupled; Data; Data Analyses; Depth; Development; Dropout; Electrical Engineering; Experimental Designs; Frequencies; Functional Magnetic Resonance Imaging; Goals; Human; Image; Imaging Techniques; Immunity; Invasive; Localized; Magnetic Resonance Imaging; Maps; Measures; Methods; Monitor; Morphologic artifacts; Nature; Neurons; Neurosciences; Numbers; Oxygen; Perfusion; Physics; Physiology; Procedures; Psychology; Radioactive Tracers; Radiology Specialty; Range; Research Project Grants; Resolution; Scanning; Signal Transduction; Source; Sterile coverings; Structure; Techniques; Technology; Tissues; Variant; Veins; Venous; Visual system structure; base; blood oxygen level dependent; capillary; computerized data processing; deoxyhemoglobin; image warping; improved; reconstruction; response; size; tool

DESCRIPTION (provided by applicant): Functional magnetic resonance imaging (fMRI) has revolutionized the neurosciences by providing noninvasive tools for monitoring changes in blood oxygenation or tissue perfusion associated with brain activation. The most common approach is blood oxygenation dependent (BOLD) imaging. Unfortunately, the MRI acquisition parameters that provide the oxygen sensitivity in BOLD also produce sensitivity to image artifacts, signal dropouts, and spatial distortion. The aim of this proposal is to develop alternatives to BOLD without these limitations. The new methods described in this proposal are based on oxygen-dependent signal changes in rapid, short TR, fully refocused imaging acquisition techniques, known as steady-state free precession, or SSFP. These approaches exploit the changes in the steady-state signal due to oxygenation changes. Once this steady-state oxygenation dependent contrast has been established, it can be captured with any image encoding method, which can be chosen for efficiency, resolution, and immunity to artifacts. The result is high-resolution, isotropic in any area of the brain, without signal dropouts or spatial distortion. This will be an important addition to the tools available to neuroscientists for studying brain activation. Specifically, this project aims to develop two different approaches for exploiting the SSFP response for fMRI. The first uses the frequency sensitivity of the SSFP transition band to detect absolute frequency shifts from blood oxygenation changes. The second exploits oxygen-dependent apparent T2 changes to the steady state magnetization. These techniques will then be evaluated and compared with conventional BOLD in well characterized studies of the visual system.

描述（由申请人提供）：功能性磁共振成像（fMRI）通过提供用于监测与大脑激活相关的血氧或组织灌注变化的非侵入性工具，彻底改变了神经科学。最常见的方法是血氧依赖（BOLD）成像。不幸的是，在 BOLD 中提供氧敏感性的 MRI 采集参数也会对图像伪影、信号丢失和空间失真产生敏感性。该提案的目的是开发没有这些限制的 BOLD 替代方案。该提案中描述的新方法基于快速、短TR、完全重聚焦成像采集技术中的氧依赖性信号变化，称为稳态自由进动或SSFP。这些方法利用了由于氧合变化而引起的稳态信号的变化。一旦建立了这种稳态氧合依赖性对比度，就可以使用任何图像编码方法来捕获它，可以根据效率、分辨率和抗伪影性来选择该方法。其结果是在大脑的任何区域都具有高分辨率、各向同性，没有信号丢失或空间失真。这将是神经科学家研究大脑激活工具的重要补充。具体来说，该项目旨在开发两种不同的方法来利用 SSFP 响应进行 fMRI。第一个使用 SSFP 过渡带的频率灵敏度来检测血氧变化的绝对频率偏移。第二种方法利用了稳态磁化强度与氧相关的表观 T2 变化。然后，这些技术将在视觉系统的充分表征研究中进行评估，并与传统的 BOLD 进行比较。