MRgRFA: Physical Model and First Order Correction of PRFS Thermometry Corrupted by Magnetic Susceptibility-Mediated Cavitations Effects

Rares Salomir¹, Magalie Viallon¹, Sylvain Terraz¹, Christoph D Becker¹

MR thermometry based on the proton resonance frequency (PRF) method (1) has gained good acceptance for guiding RF ablation of liver tumors (2). Major artifacts in the PRFS thermometry have recently been reported related to per-operatory changes of the tissue bulk susceptibility during RF heating (3). They are originating from gas bubbles formation, known as white cavitations artifacts in US imaging. We propose here a theoretical description of the effects and a first order correction that confirm the source of the spatially related errors in temperature maps and TD during power application.