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Abstract #0448

PRF Shift in Frozen Tissue at 3T.

Elena Kaye1,2, Aiming Lu3, Marcus Alley2, Kim Butts Pauly2

1Electrical Engineering, Stanford University, Palo Alto, CA, USA; 2Radiology, Stanford University, Palo Alto, CA, USA; 3University of Chicago

In clinical cryoablation temperature monitoring is typically done with temperature sensors built into cryoprobes or inserted in addition to cryoprobes. Placement of temperature sensors is invasive, time consuming, and doesnt provide continuous temperature feedback throughout the region of treatment. The following MRI parameters have been shown to be sensitivity to temperature: signal intensity, R2*, and phase shift. The phase shift is a parameter that is usually used for MRI-based thermometry in tissue at T>0 C. In frozen tissue, there is still little known about the phase and proton resonance frequency (PRF) shift dependence on temperature. In a previous 7T spectroscopy study, PRF shift as a function of temperature was found to go from a linear temperature dependence at T>0 C to an exponential dependence at T<0 C. In this work, for the first time, we measure frequency shift in frozen tissue on a clinical 3T MRI scanner.