CT Image Changes And Efficacy Evaluation Of Thermal Ablation Of Pulmonary Malignancy

Objective To study the CT appearances and evolutions of thermal ablation of pulmonary malignancy in order to accurately evaluate its efficacy.To explore the best period and evaluation criteria for the early efficacy evaluation of CT after thermal ablation of pulmonary malignancy,and to find tumor survival or recurrence in time.Methods A total of 51 lesions were collected from 41 patients undergoing thermal ablation of pulmonary malignant tumors in zhejiang cancer hospital from January 2015 to December 2018.Patients were divided into complete ablation group(group A)and incomplete ablation group(group B)according to the specialist consensus of primary and metastatic pulmonary tumor on thermal ablation therapy-2017 edition.By comparing and analyzing the CT imaging characteristics of the patients in the two groups at immediately,1 month,3 months,6 months and 12 months after the surgery,the optimal period and evaluation criteria for the early efficacy evaluation of CT after the thermal ablation of lung malignant tumor were summarized.Results ? The changes of the size and shape of the lesion:Immediately after the thermal ablation,all the lesions were significantly larger than those of pre-treatment,and ground-glass opacity is visible around the lesion with indistinct edges.There was a significant difference in the minimum width of ground-glass opacity between the two groups(P<0.05).After that,the ablated lesion of patients in group A gradually reduced in size,with sharp and clear edges,and the final appearances were fibrosis,cavities and nodules.the ablated lesion of patients in group B were first reduced and then increased,presenting nodules or lumps,and lobules were gradually evident.There was no significant difference in the size of the lesion between the two groups 1 month and 3 months after surgery(P>0.05),and there was significant difference in the size of the lesion between the two groups at 6 months and 12 months after the ablation(P<0.05).?The changes of the density on CT(in Hounsfield units)of the lesion:Immediately after the thermal ablation,the ablated lesion density of two groups became lower than that of pre-treatment.There was no significant difference between the two groups in the CT enhancement of the lesion at 1 month and 3 months after the ablation(P>0.05).At 6 months and 12 months after the ablation,there was a significant difference in CT enhancement(P<0.05),group A showed slight enhancement(<10HU)group B showed heterogeneous obvious enhancement(>15HU).Conclusion The CT image presentation after thermal ablation of malignant lung tumors are constantly changing,and regular postoperative follow-up is helpful to observe and judge the efficacy.The minimum width of ground-glass opacity around the lesion immediately after the ablation is of great significance in predicting the efficacy evaluation.The size change and enhancement range of ablated lesion are the main imaging indexes to judge the therapeutic effect of lesions.The size change and enhancement range of ablation foci are of great value to evaluate the efficacy.After 1 month and 3 months,the ablation foci showed abnormal enhancement,and tumor residue could be considered early.For most lesions,six months after the ablation is the best period for early therapeutic effect of thermal ablation,which can be recommended as the key time point for reexamination.