PRFS-Based MR Thermometry Is Hampered by Susceptibility Changes Caused by the Heating of Fat: Experimental Demonstration

Sara Maria Sprinkhuizen¹, Chris J. Bakker¹, Lambertus Wilhelmus Bartels¹

Susceptibility (χ) related field changes are commonly ignored in the application of proton resonance frequency shift (PRFS)-based MR thermometry (MRT) during thermal interventions, even though the temperature dependence of the χ of fat is in the same order of magnitude as the temperature dependence of the chemical shift of water. Its influence on PRFS-based MRT maps was investigated experimentally. The results showed that changes in χ _fat hamper the PRFS-based MRT method nonlocally. The measured errors were ranging between -4.6 C and +4.1 C. Important to stress is the fact that fat suppression is not a solution for this effect.