Wide-bore Short-bore 3.0T MRI Neuroscanner

Van Zijl, Peter

Abstract

At present, no high field (>1.5T) human scanner is available for extramural research in the state of Maryland. We propose to acquire a 3 Tesla wide-bore MRI instrument to upgrade the F.M. Kirby Research Center for Functional Brain Imaging at the Kennedy Krieger Institute to a state of the art high field MRI facility. Investigators at the Kennedy Krieger Institute, Johns Hopkins University, and the University of Maryland presently have 15 NIH-funded grants (see Tables 1, 2) with several aims than can strongly benefit from the improved technical capabilities at the high field strength of 3T compared to the presently available equipment at 1.5T. These investigators presently use the 1.5T system in the F.M. Kirby Research Center for studies related to functional MRI, quantitative physiological MRI (e.g. absolute blood flow experiments), magnetic resonance spectroscopy (MRS) and spectroscopic imaging (MRSI), and diffusion tensor imaging (DTI). This proposed 3 Tesla instrument will provide the following benefits for the users: 1) All studies will benefit from the increased signal-to-noise ratio (SNR) by a factor of approximately two. Such an increase in SNR would allow either a reduction in scan time by a factor of four or an increase in spatial resolution (voxel size) by a factor of two. This is especially important for the DTI studies that many of the projects are performing. 2) Several of the projects study functional MRI using the BOLD effect, which increases at least linearly with the magnetic field. It has also been shown that BOLD data at high field reflect more of the microvasculature instead of large vessels. In addition, spin-echo BOLD effect may become better measurable, allowing their use for the study of frontal lobe and in the quantification of physiological parameters. 3) The prolonged T1 at high field should allow improved sensitivity for arterial spin-labeling studies of absolute cerebral blood flow. 4) Spectroscopy studies should benefit from the increased chemical shift separation. Furthermore, coupled spins, such as those in glutamate, glutamine, and myoinositol, should become better distinguishable as they approach the weak coupling limit. The 3T is essential for continued high-quality state-of-the-art research at our institutions.