The goal of this protocol is to optimize new technology that enables Magnetic Resonance Imaging (MRI) at a static magnetic field strength of 7 Tesla (7T). Techniques will be developed for anatomical, functional, and spectroscopic MRI that can take advantage of this high field. Routine clinical MRI has been performed at 1.5T for over twenty years and over the past ten years MRI at 3-4T has demonstrated large increases in sensitivity and is beginning to find widespread application for functional imaging of the brain and clinical research. Since the late 1990's it has been possible to produce magnets with field strengths between 7-9T large enough for human use. Indeed there are presently two sites with 7T and one with 8T MRI that have begun to produce exciting images. These initial results confirm that MRI can be performed safely at these high field strengths and that the whole range of MRI experiments can be performed. We will take delivery of the first 7T MRI system produced by General Electric, the leading producer of MRI equipment, sometime in late 2002/early 2003. Compared to 3-4T, the 7T scanner is expected to improve sensitivity by a factor of two and improve contrast to noise for functional imaging and spectroscopy by a factor of two - four. However, realizing these goals for routine practice and whole brain coverage will require technical developments and integrating these developments into optimized data acquisition and processing strategies. Therefore, we plan to extend parallel imaging strategies, currently becoming available for 3T MRI, to 7T in order to realize the full gain in sensitivity and apply these techniques to obtain high resolution anatomical MRI, generate high temporal and spatial resolution perfusion images using arterial spin labeling techniques, generate high-temporal and spatial resolution functional images of the brain using blood oxygenation (BOLD) and perfusion based techniques, and test the usefulness of 7T for spectroscopic studies of metabolites of the brain. All of these developments will be performed on normal, healthy volunteers.
- INCLUSION CRITERIA: Only neurologically and psychiatrically normal, male or female, healthy volunteers over 18 years old will be used in these studies. Subjects must be capable of understanding the procedures and requirements of this study. Subjects must be willing to sign an informed consent document. EXCLUSION CRITERIA: A subject will be excluded if he/she has a contraindication to MR scanning such as the following: pregnancy, aneurysm clip; implanted neural stimulator; implanted cardiac pacemaker or auto-defibrillator; cochlear implant; ocular foreign body (e.g. metal shavings or insulin pump), dental work such as crowns or bridges with indeterminate metals, pre-existing eye conditions, and any pre-existing hearing problems. Subjects who underwent brain surgery, who have a neurological lesion, a psychiatric history or a history of migraine will also be excluded from this study. The contraindications for MRI at 7T are identical to those at 1.5T and 3T.