Motivation: OGSE (Oscillating Gradient Spin Echo) is a powerful tool for time-dependent diffusion MRI to detect cell structures at the micron scale. It requires strong gradient to provide b-value at a certain oscillating frequency, which will introduce significant mechanical vibration in the gradient coils. Goal(s): Our study aims to optimize the trapezoidal oscillating gradient to mitigate the mechanical vibration. Approach: A convex optimization problem is designed to reduce vibration by minimizing vibration level predicted by the system frequency response function, while ensuring the b-value and OG encoding spectrum through multiple constraints. Results: Optimized OG waveform can achieve vibration reduction up to 3dB on RMS. Impact: OG caused mechanical vibration poses significant challenge to MRI hardware, especially in high-performance gradient system. Our vibration optimized OG waveforms can improve subject's comfort and have potential to enable more precise parameter fitting, enhancing the accuracy of microstructural imaging.
Chen et al. (Tue,) studied this question.