Impact of ablation heat sink effect on the lesion range after liver MWA at different times and powers

Background: During microwave ablation (MWA) treatment, the heat sink effect can cause incomplete ablation. We discussed the influence of the effect by comparing the lesion ranges of in vitro and vivo. Method: Twenty rabbits were divided into four groups with MWA power and time set at 20W-1min, 20W-3min, 30W-1min, and 30W-3min. Compare the range of ablation lesions in vivo and in vitro under a microscope. Results: The 20W-1min group and the 30W-3min group: there were not differences in the sizes of each diameter line of the lesion in vivo and in vitro (P > 0.05). The 30W-1min group: there were statistically significant differences in the major and minor axis and the area of lesion including edema zone (P  0.05); The 20W-3min group: showed statistically significant differences in the major and minor axis and the area of coagulation necrosis lesion and lesion including edema zone (P  0.05). Conclusion: The heat sink effect becomes more pronounced as the heat increases. However, after exceeding the thermal damage threshold that the tissue can withstand, the influence of the heat sink effect on MWA lesions will gradually weaken.