Multi-Modal Approach to Understand BOLD fMRI Image-Contrast

06/30/98 该奖项支持开发新方法，以增强耶鲁磁共振中心7T水平孔光谱仪的NMR成像和光谱性能，用于定量血氧水平依赖（BOLD）功能性MRI（fMRI）图像对比度。 该项目的主要意义在于它将为将BOLD图像转换为神经元活动图提供基础。 对动物的放射自显影研究和对人类的PET研究通过以高空间分辨率检测脑灌注和代谢的改变，提供了定量测量脑活动变化的标准。 然而，这些技术的主要缺点是，这两种方法都需要放射性示踪剂和神经元活动的时间变化不能监测。 相比之下，BOLD功能磁共振成像方法不需要外源性示踪剂，并提供了大脑活动的动态测量。 拟议的项目将允许BOLD信号与脑代谢和灌注定量相关，提供一种定量MRI方法来探测与脑活动相关的生理参数。 一种非侵入性和非放射性的方法来定量映射哺乳动物大脑中神经元活动的变化将是神经科学中一个非常重要的工具。 应用将包括感觉和认知功能的大脑绘图，患病或受伤大脑中改变的大脑活动的评估，以及大脑发育和功能可塑性的长期研究。

06/30/98 This award supports the development of new methodology to enhance the NMR imaging and spectroscopy performance of the 7T horizontal bore spectrometer at Yale Magnetic Resonance Center for quantitative blood-oxygenation level dependent (BOLD) functional MRI (fMRI) image-contrast. The main significance of this project is that it will provide the fundamental basis for converting the BOLD images into neuronal activity maps. Autoradiography studies on animals and PET studies on humans have provided the standards for quantitative measurements of changes in cerebral activity by detecting alterations in cerebral perfusion and metabolism at high spatial resolution. However, the major disadvantages of these techniques are that both methodologies require radioactive tracers and temporal alterations in neuronal activity cannot be monitored. The BOLD fMRI method, in contrast, does not require exogenous tracers and provides a dynamic measure of brain activity. The proposed project will allow the BOLD signal to be quantitatively related to cerebral metabolism and perfusion, providing a quantitative MRI method of probing the physiological parameters that are coupled to cerebral activity. A non-invasive and non-radioactive method for quantitatively mapping alterations in neuronal activity in the mammalian brain would be a very important tool in neuroscience. Applications would include brain mapping of sensory and cognitive functions, assessment of altered cerebral activity in the diseased or injured brain, and long- term investigations of brain development and functional plasticity.