Motivation: In portable low-field MRI, echo-planar acquisitions suffer from severe distortions due to significant field inhomogeneity. Goal(s): To apply spatiotemporal encoding (SPEN) MRI on a 110 mT portable low-field system, aiming for fast distortion-free imaging. Approach: SPEN imaging parameters were optimized by leveraging the reduced SAR at low field strengths. SPEN-based 2D, 3D imaging, and DWI were compared with EPI on a 110 mT system. Additionally, cross-term spatiotemporal encoding (xSPEN) was implemented for in vivo and implant imaging. Results: SPEN-based imaging demonstrated comparable image contrast and acquisition time to EPI-based methods with reduced geometric distortions. Impact: SPEN-based MRI provides a robust and fast acquisition approach to obtain distortion-free images at low-cost portable low field systems, thereby expanding the prospects for rapid imaging, navigation, functional and implant imaging in low-field portable MRI.
Qiu et al. (Tue,) studied this question.