MR Thermometry by Quadratic Phase MR Fingerprinting

PRF-shift thermometry is the current standard for MR-based temperature monitoring in interventional procedures and works by converting gradient-recalled image phase changes to temperature changes. However, the long TE required for phase contrast increases sensitivity to artifacts from motion. We propose to address this using quadratic phase MR fingerprinting (qRF-MRF) which is robust to spurious artifacts. We implemented a qRF-MRF sequence that sweeps continuously across resonance frequencies and is highly sensitive to heating-induced resonance frequency changes. The sequence was used to monitor laser heating in a phantom, with comparison to GRE thermometry.