Correction of Proton Resonance Frequency Shift Temperature Maps for Magnetic Field Disturbances Using Fat Signal
Harvey P, Shmatukha A, Bakker C
Philips Medical Systems
The Proton Resonance Frequency Shift (PRFS) method of MRI temperature mapping is sensitive to magnetic field disturbances. Such disturbances are misinterpreted as artifact temperature changes. Our technique uses the fat signal, which does not exhibit a temperature-dependent frequency shift, for recovering correct PRFS temperature maps. It is based on the utilization of two gradient echoes acquired around an RF echo within one repetition interval using water- and fat-selective scans as well as a specially designed post-processing algorithm. Accurate and reliable temperature estimations were obtained in phantom experiments in spite of inter-scan motion and field disturbances up to 1.4 ppm.