RF Shield design for transmit coils to reduce acoustic noise in MRI

Motivation: Eddy currents induced in the RF shield cause vibrations which generate acoustic noise. Goal(s): To develop an RF shield that minimizes eddy currents and preserve the B1+ efficiency. Approach: It was established that eddy-currents induced in the RF shield of the transmit coil are the primary source of acoustic noise in our 7T scanner. Therefore, the conventional slotted double layered RF shield was replaced by a segmented phosphor bronze mesh (PBM) to minimize eddy-currents and acoustic noise. Results: Measurements performed at both ear locations of an anthropometric phantom demonstrate that the segmented PBM-based RF shield reduces the acoustic noise by up to 10dB. Impact: Acoustic noise reduction could be achieved by using segmented PBM without compromising the transmit B1 field compared to the conventional double-layered slotted shield. Further improvements might be achieved with different mesh configurations besides the one implemented in this work.