Acoustic Noise Optimization of Trapezoid Oscillating Diffusion Encoding Gradient

Motivation: Oscillating gradient spin-echo (OGSE) diffusion MRI sequence involves diffusion preparation and EPI readout, both having rapidly switching trapezoid gradient. Consequently, OGSE sequence generates strong acoustic noise that may introduce comfortless patient experience. Goal(s): Our study aims to develop an optimization framework to suppress the acoustic noise by softening the trapezoid gradient. Approach: We measured the acoustic noise frequency response function of scanner. Based on linear model of MRI acoustic noise generation, we designed a convex optimization framework to reduce the predicted A-weighting sound pressure level(SPL) Results: Optimized gradient achieved 14.09dBA SPL reduction according to our FRF based prediction. Impact: We developed an effective optimization method to reduce the acoustic noise of oscillating trapezoid gradient waveform, and potentially facilitate the clinical applications of OGSE. This optimization framework also has potential to reduce acoustic noise of EPI readout waveform