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是在1.5或3.0特斯拉的相对较低磁场下进行的。然而，理论考虑和实验证据表明，图像的信噪比、功能成像对比度和空间特异度与磁场强度有根本的依赖关系。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，在人类身上，功能成像研究只在高达7特斯拉的领域进行。许多实验数据表明更高的实地研究具有优势，这些数据是通过动物模型获得的。虽然动物研究为我们提供了在某些情况下可以阐明MRI/fMRI的生物物理学的数据，但它们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的研究都是使用有限的视野和/或单个或几个切片来完成的。较短的T2*S、增加的磁化率效应、增加的生理噪声、增加的SAR和不均匀的B1场都会阻碍高磁场所提供的优势。为了缓解与这些问题相关的一些问题，从而使高场成像对整个大脑的一般应用更具吸引力，需要技术开发。随着包括发射和接收线圈阵列在内的并行成像和并行成像技术最近的增长和发展，在强磁场下经常观察到的这些问题中的许多可以被解决。此外，序列修改和新的序列设计也有助于显著减少与高实地研究相关的技术问题。这项建议的总体目标是发展功能磁共振成像和磁共振成像技术，用于在强磁场(7T和9.4T)下进行全脑采集。为了实现这一目标，将首次在9.4特斯拉的超高磁场下进行人体fMRI/MRI研究。此外，我们还将系统地比较高场系统和低场系统(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.