An apparatus for performing a medical treatment, comprising an invasive probe and a processor coupled to the probe. Energy is applied through the probe to ablate tissue at a plurality of sites in an organ in a body of a patient, thereby creating lesions in the tissue including at least first and second lesions at respective first and second, mutually-adjacent sites. The processor is configured to record location coordinates and respective treatment parameters at each of the sites with respect to the applied energy. Based on the recorded treatment parameters, respective measures of size of the lesions are computed, including at least respective first and second measures of the first and second lesions. An indication of contiguity between at least the first and second lesions is generated responsively to the first and second measures and to a distance between the location coordinates of the first and second sites.
