Fig. 2.

Gross pathology of a lung specimen from the triple-freeze protocol group, which was stained with triphenyltetrazolium chloride (TTC). The transition from nonviable tissue centrally to the darkly stained, viable tissue surrounding the ablation zone can be clearly seen (arrow). In addition, one can see the inner halo related to the triple-freeze protocol within the ablation zone (curved arrow). Although it was not directly studied, it is likely that the asymmetry in growth was related to central heat sinks, such as blood flow and air exchange, limiting the growth along the more central border