Gradient impulse response function-based phase compensation for wavelet MR elastography on a compact 3T scanner

Abstract

Motivation: High-performance asymmetric gradient systems have the potential to produce high-spatial-order eddy-current-induced magnetic fields that can impact phase-based applications such as wavelet MRE using large-magnitude motion-encoding bipolar gradient pulses. Goal(s): Removal of the gradient-system-induced high-order phase deviation in the wavelet MRE phase map. Approach: Gradient impulse response functions (GIRFs) can be used to characterize the gradient system. We introduce a GIRF-based phase compensation approach to alleviate the high-order phase deviations resulting from imperfections in the gradient system, along with practical recommendations, including the use of a tailored set of GIRFs. Results: The phase inhomogeneity in wavelet-MRE phase map improved with the GIRF-based compensation. Impact: The proposed GIRF-based phase compensation approach offers the potential to enhance phase image quality and accuracy, addressing imperfections in the gradient system, which is a challenge not fully resolved by alternative methods like concomitant field correction and pre-emphasis gradient modification.