Magnetic resonance (MR) imaging and spectroscopy are used to non-invasively acquire structural, functional, and biochemical information in humans, and further utilizing this capability for diagnostic purpose. The research trends in MR systems have moved towards ultrahigh magnetic field (B0) strengths and multichannel radiofrequency (RF) coils. There, however, are unsolved technical problems in RF coils and its interface circuits: loading effect due to variable subject loads, and an increasing number of RF coil elements. The loading effect requires the difficult and time-consuming manual frequency tuning and impedance matching. Multichannel systems, which enable parallel MR imaging, require miniaturization of coil elements and interface circuits to prevent RF interference and be able to fit into the bore of MR scanners. To overcome these challenges, this application entitled Automatic RF signal tuning and matching system for MR imaging and spectroscopy proposes an electrically driven automation system to tune and match RF coils rapidly and accurately. The automatic system will be implemented on a custom designed MR- compatible microchip. We have recently presented the feasibility of applying the automatic system in a multichannel RF transceiver coil for hydrogen proton (1H) imaging at 7T. During mentored phase (K99), the candidate will gain non-hardware knowledge in MRI, such as MR physics, RF pulse, MR sequence, and MR spectroscopy, to develop specialized RF pulses and MR sequences that take advantage of the electrical circuits embedded in an RF coil. With a set of hardware and non-hardware knowledge, the candidate will develop an automatically frequency tuned and impedance matched multi-nucleus (1H and 31P) RF coil during the mentored period. Subsequently, a miniaturization of the automatic system with a custom- designed MR-compatible microchip will be accomplished during the R00 period. This microchip will have wireless control capability in addition to the automated functions (frequency tune and impedance match). The specialized RF pulse and sequence will assist the operation of the microchip. This microchip solution will have significant benefits: applying the automatic functions in or out of magnet bore and before or during MR experiments, preventing RF interferences due to short wavelength at ultrahigh field, reducing the size of the automated system for supporting a large number of coil elements, and eliminating RF/electrical interconnection wires and cables. Furthermore, this technology has the potential to integrate additional functions and systems into a MR-compatible custom-designed microchip. The successful completion of this interdisciplinary project will enable the candidate to become an independent investigator in the area of next- generation MR technology.
Magnetic Resonance Imaging (MRI) is one of the most state-of-the-art technologies in the armamentarium to produce detailed images of the human body and is trying to welcome the world of ultrahigh field MRI systems. Innovation of radiofrequency (RF) coils and interface electronics is an indispensable part to overcome technical barriers at ultrahigh field. This project proposes an automatically controlled RF coil and its system integration that will compel advancement to fulfill the full potential in detection and diagnosis o health and diseases at ultrahigh field MRI scanners.
|Sohn, Sung-Min; Gopinath, Anand; Vaughan, John Thomas (2016) A Compact, High Power Capable, and Tunable High Directivity Microstrip Coupler. IEEE Trans Microw Theory Tech 64:3217-3223|
|Sohn, Sung-Min; Vaughan, J Thomas; Lagore, Russell L et al. (2016) In vivo MR imaging with simultaneous RF transmission and reception. Magn Reson Med 76:1932-1938|