The focus in the RF lab is to develop transmit arrays that provides control over the B1+ field for RF shimming and dynamic parallel transmission methods. The transmit arrays are combined with tight fitting receive arrays for increased receive sensitivity. Precise numerical simulation and safety evaluation are carried out to ensure safe in-vivo use. Travelling wave imaging and prospective motion correction using NMR field probes are being explored.
The promise of increase in signal to noise ratio (SNR) proportional to the main magnetic field strength motivated a few academic laboratories to pursue magnetic resonance imaging (MRI) research at ultra-high field (UHF, ≥ 7 T), much higher than the field strength approved for clinical use. The magnetic resonance center of our institute is equipped with a 9.4 T scanner, the strongest magnet ever used for human MRI till date.
Radio frequency (RF) coils and the front-end RF hardware play a significant role in realizing the benefits offered by this unique scanner. In addition to conventional 1H imaging, multi nuclei imaging / spectroscopy is expected to gain from the increased field strength. UHF MRI operates in a regime where the shorter wavelength in tissue due to the high Larmor frequency leads to constructive and destructive interference of the transmit (B1+) field inside the human body. Hence, it is not only challenging but also opens up opportunities to develop novel methods for excitation.
The focus in the RF lab is to develop RF transmit arrays that provides control over the B1+ field for RF shimming and dynamic parallel transmission (pTx) methods together with precise numerical simulation to accurately estimate specific absorption rate (SAR). Anatomy specific, form-fitting receive arrays are combined with transmit arrays to increase the image SNR. Alternative approaches for spin excitation utilizing the waveguide properties of the scanner bore and prospective motion correction using NMR field probes are being explored.