Computer modeling demonstrated that microwave ablation achieved higher maximum tissue temperatures (177°C vs 100°C) and was less affected by tissue perfusion compared to radiofrequency ablation.
Does microwave ablation differ from radiofrequency ablation in tissue heat transfer and susceptibility to perfusion in a computer model of hepatic tissue?
Microwave ablation achieves higher tissue temperatures and requires shorter treatment times than radiofrequency ablation, making it less susceptible to the cooling effects of tissue perfusion.
Absolute Event Rate: 177% vs 100%
Both radiofrequency (RF) and microwave (MW) ablation devices are clinically used for tumor ablation. Several studies report less dependence on vascular mediated cooling of MW compared to RF ablation. We created computer models of a cooled RF needle electrode, and a dipole MW antenna to determine differences in tissue heat transfer.We created Finite Element computer models of a RF electrode (Cooled needle, 17 gauge), and a MW antenna (Dipole, 13 gauge). We simulated RF ablation for 12 min with power controlled to keep maximum tissue temperature at 100 masculineC, and MW ablation for 6 min with 75 W of power applied. For both models we considered change in electric and thermal tissue properties as well as perfusion depending on tissue temperature. We determined tissue temperature profile at the end of the ablation procedure and calculated effect of perfusion on both RF and MW ablation.Maximum tissue temperature was 100 masculineC for RF ablation, and 177 masculineC for MW ablation. Lesion shape was ellipsoid for RF, and tear-drop shaped for MW ablation. MW ablation is less affected by tissue perfusion mainly due to the shorter ablation time and higher tissue temperature, but not due to MW providing deeper heating than RF. Both MW and RF applicators only produce significant direct heating within mm of the applicator, with most of the ablation zone created by thermal conduction.Both RF and MW applicators only directly heat tissue in close proximity of the applicators. MW ablation allows for higher tissue temperatures than RF since MW propagation is not limited by tissue desiccation and charring. Higher temperatures coupled with lower treatment times result in reduced effects of perfusion on MW ablation.
Schramm et al. (Wed,) conducted a other in Tumor ablation (liver tissue simulation). Microwave ablation vs. Radiofrequency ablation was evaluated on Maximum tissue temperature (°C). Computer modeling demonstrated that microwave ablation achieved higher maximum tissue temperatures (177°C vs 100°C) and was less affected by tissue perfusion compared to radiofrequency ablation.