The specific acquisition desired in this application is a eight-channel radiofrequency (RF) transmit front-end capable of generating channel-specific, user- defined RF pulse patterns to drive independent transmit elements in a multichannel transmit or transmit/receive RF array-coil at 7Tesla. The proposed hardware will be incorporated into an existing 7Tesla instrument located within the University of Minnesota's Center for Magnetic Resonance Research (CMRR). This 7 Tesla is the central instrument in the NIH-funded Biotechnology Research Resource Center (P41 RR08079) and the Neuroscience Blueprint Center Core (P30 NS057091) located at the CMRR, and, in this capacity, supports a large number of NIH funded investigators and projects both within and outside of the University of Minnesota. As such, the proposed upgrade will impact a large number of users. This request is based on the fact that imaging in general and magnetic resonance (MR) imaging in particular has evolved to become an indispensible part of contemporary basic and clinical biomedical research, central to discoveries in a large number of disciplines. In this development, recent work has established that ultrahigh magnetic fields (7 Tesla) provide numerous advantages and are emerging at the forefront of this methodology. However, conventional means of exciting MR signals are suboptimal in the brain and simply do not work in the human body at 7 Tesla where the RF wavelength at the proton resonance frequency is ~12 cm and, thus, smaller than the dimensions of the human head or body. In this regime, the radiofrequency (RF) field generated by conventional single, channel transmit systems, is highly non-uniform and power consumptive for most biomedical applications. Solutions to this problem depend on the ability to dynamically control the RF excitation field over a number of degrees of freedom. The proposed instrument is capable of achieving this and is indispensible in the optimal use of the 7 Tesla platforms on human studies.
Magnetic resonance imaging (MRI) is one of the most powerful tools in the armamentarium of techniques employed to investigate the biomedical complexities of the human body in health and disease. This proposal requests funds for instrumentation that will provide a significant enhancement in MRI by enabling the use of higher magnetic fields, which provide significant gains provided that challenges associated with them, can be solved.
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