Dara L. Kraitchman1, 2, Di Qian1, 3, Paul A. Bottomley1, Clifford R. Weiss1
1Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, MD, United States; 2Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, United States; 3Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, United States
MR-compatible cryoablation therapy was originally developed on low field systems to treat cancer. Ancedoctal evidence suggests that heating of the cryoprobes may occur. Using a realistic whole body phantom that approximates human body conductivity, we determined the specific absorption rate (SAR) of a clinical approved cryoablation system using fiber optic probes on a 1.5 T MR system. A standard cardiac multislice cine SSFP sequence achieved peak SAR levels of 5.4. Using a real-time SSFP sequence, transient heating changes exceeding 15C were noted. These results should be taken into account during MR-guided cryoablation procedures.