A method and system for determining contact assessment includes the steps of positioning a catheter at a tissue treatment site, where the catheter has a proximal end portion and a distal end portion, the proximal end portion defining at least one fluid inlet port and at least one fluid outlet port, an expandable membrane defining a cooling chamber a coolant injection lumen in fluid communication with the at least one fluid inlet port and the cooling chamber, a coolant return lumen in fluid communication with the at least one fluid outlet port and the cooling chamber, the coolant injection tube, the cooling chamber, and the primary coolant return lumen defining a fluid pathway and a temperature sensor located near the coolant return lumen; measuring an internal temperature of the chamber, and modifying the position of the catheter in response to the measured temperature. The method and system can also use a measured impedance to determine contact assessment.