FUNCTIONAL MRI IN HUMANS AT 7 TESLA

描述（申请人提供）：目前绝大多数磁共振成像和功能成像研究都是在相对较低的1.5或3.0特斯拉磁场下进行的。然而，理论考虑和实验证据表明，图像信噪比、功能成像对比度和空间特异性与磁场强度有基本的依赖关系。最近，有人提出，即使是常规的解剖成像在高磁场下也有潜在的优势。到目前为止，在人体中，功能成像研究只在高达7特斯拉的电场下进行。许多实验数据表明，更广泛的实地研究的优势是通过动物模型获得的。虽然动物研究为我们提供了一些数据，可以在某些情况下阐明MRI/fMRI的生物物理学，但它们并不一定完全适用于人脑。此外，几乎所有在高磁场下对人类或动物进行的研究都是使用有限的视野和/或单个或少数切片完成的。较短的T2*s、增加的磁化效应、增加的生理噪声、增加的SAR和不均匀的B1场都会阻碍高磁场带来的优势。为了减轻与这些问题相关的一些问题，从而使高场成像对全脑的一般应用更具吸引力，需要技术发展。随着近年来并行成像和并行成像技术的发展，包括发射和接收线圈阵列，许多在高磁场下常见的问题可以得到解决。此外，序列修改和新序列设计也有助于显著减少与高野外研究相关的技术问题。本提案的总体目标是发展fMRI和MRI技术，用于高磁场下的全脑采集（7 T和9.4 T）。为了实现这一目标，将首次在9.4特斯拉的超高磁场下对人体进行fMRI/MRI研究。此外，我们将系统地比较高场系统与低场系统（3t）在一般应用中的优势。

DESCRIPTION (provided by applicant): Currently, the vast majority of magnetic resonance imaging and functional imaging studies are conducted at relatively low magnetic fields of 1.5 or 3.0 Tesla. However, theoretical considerations as well as experimental evidence have suggested that there is a fundamental dependence of image signal to noise ratios, functional imaging contrast and spatial specificity on the magnetic field strength. More recently, it has been suggested that even routine anatomic imaging has potential advantages at high magnetic fields. Thus far, in humans, functional imaging studies have only been done at fields as high as 7 Tesla. Much of the experimental data suggesting advantages for higher field studies have been acquired using animal models. While animal studies provide us with data that can elucidate the biophysics of MRI/fMRI in certain cases, they are not necessarily fully applicable to the human brain. Furthermore, almost all of the studies in humans or animals at high magnetic fields have been done using limited field of views and / or a single or few slices. Shorter T2*s, increased susceptibility effects, increased physiological noise, increased SAR, and inhomogeneous B1 fields can all hinder the advantages offered by high magnetic fields. To alleviate some of the problems associated with these issues and thereby making high field imaging more attractive for general applications of the whole brain, technical development is required. With the recent growth and development of parallel imaging and parallel imaging techniques, including transmit and receive coil arrays, many of these problems commonly observed at high magnetic fields can be addressed. In addition, sequence modification and new sequence design can also help to significantly reduce the technical problems associated with high field studies. The general aim of this proposal is development of fMRI and MRI techniques for whole brain acquisitions at high magnetic fields (7 T & 9.4 T). In achieving this aim, fMRI/MRI studies will be conducted at the ultra-high magnetic field of 9.4 Tesla for the first time in humans. Furthermore, we will systematically compare the advantages of higher field systems with lower field systems (3 T) for general applications.