To Study The Effectiveness Of Percutaneous Microwave Ablation By CT Guided Under Different Conditions In Lung Model

Objective To study the range of CT ablation after immediate ablation of normal rabbit lung tissue under different parameters of microwave ablation.To observe the pathological changes of lung tissue injury induced by microwave ablation in live rabbits.To provide experimental evidence for clinical treatment and follow-up.To obtain a certain range of ablation,the pathological changes of microwave ablation under different conditions were discussed.Methods 1?18 experimental rabbits underwent percutaneous microwave ablation in sequence in both lungs.According to different ablation parameters,they were randomly divided into 4 groups:20w3min(group A),20w5min(group B),40w3min(group C)and 40w5min(group D)to obtain 36 ablation sites.The maximum longitudinal diameter L and the maximum transverse diameter D of the ablation were observed by CT scanning immediately after ablation,and the maximum cross-section area S was calculated.2?Thirty-six lesions were obtained by microwave ablation in 18 experimental rabbits,which were sacrificed by 50ml air embolization immediately,2 weeks and 4 weeks.After complete removal of lung tissue,pathological sections were made,and pathological characteristics were observed and analyzed.3?Twelve ablation lesions were obtained from 6 experimental rabbits,which were divided into 4 groups:20w3min(group A),20w5min(group B),40w3min(group C)and 40w5min(group D).CT scan was performed immediately after microwave ablation.After the CT examination,50ml air embolization was injected into the ear vein,and pathological examination was performed on the ablation lesions of the experimental rabbits.Results1?The longest longitudinal diameter of ablation lesions in group A,B,C and D was(12.04±0.72mm,15.67±0.64mm,16.4±1.18mm,19.65±2.08mm),the longest transverse diameter was(9.26±0.92mm,11.4±0.93mm,12.38±1.16mm,13.91±1.26mm),and the maximum cross sectional area was(88.80±7.29mm2,151.1±8.47mm2,150.27±7.98mm2,200.18±5.88mm2).The longest longitudinal diameter L and the longest transverse diameter D between groups A,B,C and D passed the normal distribution and variance test,and the two groups B and C selected correction t test,P>0.05,showing no statistical significance.Independent sample t test was selected among the other groups,P<0.05,which was statistically significant.2?Immediately after ablation,the ablation lesion showed acute heat injury under pathological microscope.In the center of the lesion,the needle cavity and part of alveoli were vaporized,the adjacent alveolar structure was squeezed,and the area of coagulative necrosis with the nucleus disappeared was seen.A large number of inflammatory cells infiltrated in the lateral alveolar cavity and alveolar hemorrhage were observed.Coagulation necrosis of one side of the vascular wall and rupture of one side of the airway wall were observed,while the other side was relatively normal.After 2 weeks,the needle cavity structure of the ablation lesion disappeared,and the entire ablation lesion showed a 2-layer structure,with coagulative necrotic tissue at the center of the lesion and lateral granulation tissue formation.After 4 weeks,the ablation showed a 3-layer structure,with coagulative necrotic tissue at the center of the ablation,a large amount of inflammatory infiltration around,and granulation tissue at the outermost.Squamous metaplasia of columnar epithelial cells is seen in the injured bronchi,and the boundary between the injured vascular wall and inflammatory cells is unclear.3?Immediately after ablation,CT images of group A,group B,group C and group D showed that the maximum area of ablation lesions were(97.63±2.22mm2,159.27±0.43mm2,156.07±3.1mm2,243.14±54.14mm2).Pathological images showed that the maximum area of ablation lesions in group A,B,C and D were(43.48±3.53mm2,98.72±0.11mm2,100.76±3.59mm2,136.80±20.54mm2),the area of ablation on pathology was smaller than that on CT,p<0.05.The area of coagulative necrosis in group B and group C were(17.45±0.86mm2,10.67±1.10mm2),the area of coagulation necrosis in group C was smaller than that in group B,P<0.05.The area of bleeding in group B and group C were(81.27±1.09mm2,89.98±4.86mm2),the bleeding area of group C was larger than that of group B,P<0.05.Conclusion 1.Percutaneous microwave ablation of experimental rabbit lung tissue can produce definite ablation effect.2.The ablation range increases with the increase of ablation time and power.3.The ablation time and ablation power can be adjusted to reach a certain ablation range.4.Heat sink effect generated by blood vessels has an impact on the effect of microwave ablation.5 Bronchial ventilation has an effect on microwave ablation.6.The damaged bronchi and blood vessels were repaired gradually over time.7.Immediately after microwave ablation,the CT scope of ablation lesions were larger than the pathological scope.8.Experimental study had shown that low power,long time and high power,short time microwave ablation can achieve similar ablation range,but the former had less damage to normal lung tissue and larger area of coagulation necrosis.