Double-Echo Single-Shot EPI for Improved MR-thermometry in the Liver at 0.55T

Motivation: Low-field MRI shows promises for image-guided therapies such as HIFU of the liver, although the need for a high temporal resolution competes with the intrinsically lower SNR of MR-thermometry at 0.55T. Goal(s): To improve the precision of MR-thermometry of the liver at 0.55T. Approach: A double-echo single-shot EPI sequence for MR thermometry was implemented and evaluated in a phantom and 8 healthy volunteers. The proposed sequence was compared to 2 other single-echo sequences with matching imaging parameters. Results: The proposed dual-echo single-shot EPI thermometry sequence resulted in superior temperature precision versus reference standard single-echo EPI thermometry sequences at 0.55T. Impact: Low-field MRI shows promises for image-guided therapies such as HIFU of the liver. The proposed double-echo single-shot EPI MR-thermometry sequence improved the precision of MR-thermometry in the liver at 0.55T while maintaining a high framerate.