Ultra-High Performance Gradients for a 3T MRI Research Scanner

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Summary / Abstract This is an application for funding to add major new technical capabilities to a 3 Tesla magnetic resonance imaging (MRI) and spectroscopy (MRS) system that is used for neuroimaging research by a large group of NIMH-funded investigators at Vanderbilt University. The specific technology to be installed comprises novel, ultra-high performance magnetic field gradients and amplifiers that will provide much increased imaging performance especially for diffusion and functional studies of the brain. The new gradients would provide peak strengths of over 120 mT/m, three times stronger than current gradients, which would dramatically increase the quality of data (signal to noise ratio, angular and spatial resolutions, degree of distortion, spectral bandwidth) available for diffusion tractography and functional imaging and localized spectroscopy. The current scanner is heavily used by active investigators who rely on high quality MRI and MRS data for diverse research applications. MRI is well established as the single most powerful non-invasive imaging modality for studies of the brain. MRI and MRS can provide uniquely valuable information about tissue composition, structure and function, as well as quantitative descriptions of underlying biological processes. The new gradients will provide several major specific advantages. [1] higher gradient b values in diffusion MRI will allow shorter echo times, shorter diffusion times, higher signal to noise ratio, faster acquisitions and higher spatial and angular resolution in diffusion tractography of white matter; [2] stronger gradients will allow enable decreases in the effective spacing between echoes in echo planar imaging, reducing geometric distortions arising from long readouts, and allowing increased resolution in functional MRI acquisitions; [3] stronger gradients will improve localized spectroscopy and inner volume imaging by increasing signal dephasing. In this application we feature 8 selected investigators all of whom are experienced users of the current 3T scanner in a variety of NIMH- supported research applications. Their research projects all include the application of structural and functional MRI to studies of the architecture and functional organization of the brain in normal as well as neuropsychiatric conditions. The scanner is housed and managed within the Vanderbilt University Institute of Imaging Science, and operates as a core resource within our institution. The instrument will be supported by an established group of MR imaging experts and support staff. A comprehensive plan has been developed for the financial and technical support of the system as well as for its management, and the system is assured of strong institutional support and oversight.