An experimental study of EUS-guided radiofrequency ablation of porcine pancreas in vitro / 中华胰腺病杂志

ABSTRACT

Objective To investigate the extent of radiofrequency ablation of pig pancreas in vitro with various power and duration,and to establish the regression equation of radiofrequency ablation of porcine pancreas in vitro.Methods Among the 4 settings of power (from 5 w ～ 20 w) and 11 settings of duration (from 40s ～ 240s),44 combinations were selected,and every combination was performed twice,then a randomization table including 88 combinations was established,and 88 ablation procedures on porcine pancreases in vitro were performed.The uhrasonography changes were observed,ablation widths (Y) were measured,and pathological examination was performed.In order to construct optimal model and to establish the regression equation of radiofrequency ablation,9 parameters (duration,power,duration × power,the square of duration,the square of power,the square root of duration,the square root of power,the natural logarithm of duration,the natural logarithm of power) derived from duration and power were analyzed via stepwise regression method.Results A rectangular echo enhanced region was observed along the working area of catheter when radiofrequency ablation started,and it gradually became wider during ablation.A hoar-like cylindrical ablation region that was clearly different from surrounding normal pancreatic tissue was formed.Carbonation of necrotic tissue could be observed after radiofrequency ablation under 15 w or 20 w.The optimal model showed a linear positive correlation between ablation width (Y) with the square of power and the natural logarithm of duration.The coefficient of determination of this model was 0.71.Both Fitting curve and Residual scatter diagram showed good fitting effect.Finally,a significant regression equation of radiofrequency ablation was establishedY (mm) =0.005 × E2 + 0.9374 × ln (t)-0.6943.Conclusions A significant regression equation of radiofrequency ablation is established,which provides experimental base for EUS-guided radiofrequency ablation of pancreatic tumors in clinical practice.