A method of assessing a tissue ablation treatment, including positioning a medical device adjacent a target tissue measuring a first impedance magnitude a first frequency with the medical device measuring a first impedance phase at a second frequency with the medical device ablating at least a portion of the target tissue with the medical device measuring at second impedance magnitude at a third frequency with the medical device measuring a second impedance phase at a fourth frequency with the medical device comparing at least one of (i) the first and second impedance magnitudes and (ii) the first and second impedance phases and providing an indication of the efficacy of the ablation treatment based at least in part on the comparison.
