| Part?Experimental comparison study of the thyroid small unit in thermal ablationObjective Take the small thermal ablation lesions of Ex vivo fresh pig thyroid glands with microwave ablation,radiofrequency ablation and laser ablation as the research objects to compare the characteristics of the three methods in the moving-shot technique.Methods Ex vivo pig thyroid grands were randomly divided into three groups with numbers,10 cases of each group.According to pre-experimental parameters,all cases were ablated by microwave,radiofrequency and laser to obtain thyroid ablated tissue with a maximum diameter of 1cm.During ablation,the two-dimensional ultrasound changes and the maximum temperatures at the near edge of the small units of all cases in the three groups were observed and recorded,respectively.The elastic images and the elastic ratios of all cases in the three groups were measured after ablation.By dissecting along the long axis of the ablation needle track,the gross specimens of the ablated lesions wereobserved and had pathological examinations.Results 1.At the beginning of ablation,real-time ultrasound showed needle tip appeared as a strong echo area,laser was the forward emission energy,while microwave and radiofrequency were the lateral emission energy.When the ablation went on,the size of the gas echo area continued to increase.Although the border was irregular,the outline was clear at the beginning,and soon the scope of the outline became unclear.2.The measurement of the real-time temperatures near the edge of the small units showed the fastest rate of temperature rising in microwave ablation and the maximum temperature was63.88±1.53 ?;the temperature of RFA was undulated and the maximum temperature was 57.48±3.06 ?;the temperature of LA was stable and the maximum temperature was 72.24±4.32 ?.The maximum temperatures of the three groups were significant different(F=54.09,P < 0.05)and the differences between each group was statistically significant(P<0.05).3.The elastic images of the three groups showed distinguishable ablation zones,but the elastic image score was with no significant difference,The elastic ratios of the three groups were statistically significant(F=15.32,P<0.05).4.The gross specimens showed that the ablation areas were harden and oval-shaped after ablation,the shape of LA unit was round oval while the shape of RFA and MWA were narrow oval,and the ablation areas of RFA and MWA showed uniform in gray and with no carbonization and vaporization cavities,while the carbonization areas were visible in LA group.5.There were no significant differences in the longest diameters among the three groups(F=0.35,P > 0.05).6.The pathological examinations of LA lesions showed the cell shape of carbonized areas were unclear and the coagulation necrosis areas showed the degeneration of thyroid follicles,with the nucleus disappeared,pale stained cytoplasm and vacuoles inthe most follicles.The ablation areas of RFA and MWA were arranged evenly without obvious carbonization,gasification cavities and solidification necrosis areas.The surrounding tissues were demarcated clearly and the denatured thyroid follicles were seen in coagulation necrosis areas.The morphology of the cells was discernible,and vacuoles are formed in some follicles while the nuclei disappear.Conclusion The ways of emission energy of microwave,radiofrequency and laser ablation needles were different,and the conformation of thermal ablation zone through the three ablated methods was also different.The maximum temperatures of the proximal edge in the ablation zones of the three groups were different,and the degree of pathological tissue necrosis in the ablation zone was also different,which suggested that the difference in needle placement procedures and moving plans among the three ablated methods.Part ?Ultrasonic features of thyroid nodules related to the false negativity in ultrasound-guided fine-needle aspiration for suspicious malignant thyroid nodulesObjective The study was to investigate the ultrasonic features of thyroid nodules related to the false negativity in ultrasound-guided fine-needle aspiration(UGFNA)for suspicious malignant thyroid nodules.Methods The cytology findings,post-operative pathological findings and findings from follow up were retrospectively analyzed in a total of 115 thyroid nodules,and the sensitivity,specificity,positive and negative predictive values(PPV and NPV),accuracy rate,and AUC of UGFNA were determined.The nodules were divided into three groups: false-negative group,true-negative group and true-positive group.In each group,the ultrasonic features(nodule maximum diameter,multiple or solitary nodule,margin,shape,echotexture,calcification,blood flow pattern,taller-than-wide on transverse view,and hypoechoic halo),sex,and age were analyzed to identify risk factors for false negativity in UGFNA.Results The sensitivity,specificity,PPV,NPV,accuracy rate,and AUC of UGFNA were 74.5%(41/55),95%(57/60),93.2%(41/44),80.3%(57/71),85.2%(98/115)and 0.848,respectively.The maximum diameter,taller-than-wide shape,margin,and calcifications of the nodules were related to the false negativity among which the maximum diameter and calcifications of the nodules were independent predictors of false negativity(P?0.05),but there were no significant differences in sex,age,multiple or solitary nodule,echotexture and blood flow pattern(P>0.05).Conclusion UGFNA is an effective method in the diagnosis for benign and malignant thyroid nodules,but there is the possibility of false negative.So,active surveillance or repeated UGFNA are needed for the nodules which have the presence of high risk false negative such as small nodule size and intra-nodule calcification.Part ?Ultrasound-guided percutaneous thermal ablation of thyroid nodules,recurrences and metastases of PTC: a clinical studyObjective 1.To investigate the efficacy and safety of ultrasound-guided percutaneous microwave ablation of benign thyroid nodules with different internal structures;2.To evaluate the methods,the efficacy and the safety of ultrasound-guided PLA using a singer fiber for thyroid nodules,PTMCs,local recurrences and metastases of PTC;3.To assess the clinical value of RFA in thyroid nodules and cervical recurrences and the metastases of PTC with the absence of radioiodine uptake.Methods 1.A total of 53 thyroid nodules in 51 cases were treated by ultrasound-guided percutaneous MWA.The 53 nodules were the main nodules which caused symptoms and the nodules were classified into three types according to the internal structures of the nodules.Ultrasound examinations were performed after ablation at 1,3 and 6 months after initial ablation and every 6 months thereafter to evaluate the absorption of the ablation zones and calculate the nodule shrinkage ration.The thyroid functions and the cervical cosmetic scores were evaluated during the follow-up period.The intraoperative and the postoperative complications were observed as well.2.Participants included 31 patients with 29 thyroid nodules and 7 neck metastatic lymph nodes who underwent ultrasound-guided PLA with a singer fiber in one session.Among the 29 thyroid nodules,benign nodules in 13 cases including 2 cases of autonomously hyperfunctioning thyroid nodules,papillary thyroid microcarcinomas in 15 cases,local recurrences of papillary thyroid carcinoma in1 case.We took one-point ablation method,two-point ablation method or stratification multiple-points ablation method for the lesions with different size.The methods and complications as well as the clinical evaluations were recorded during PLA procedures and the follow-up period.3.There were 25 patients with33 lesions which included 13 benign thyroid nodules,8 PTMCs,12 cervical recurrences and metastases after thyroid papillary carcinoma resection underwent ultrasound-guided percutaneous RFA treatment.We took the method of retaining some residual lesions when absence of formed effective isolation fluid between the major lesions and the surrounding vital tissues when adhesion found in patients with cervical recurrences and metastases of PTC to protect the surrounding important structures.All patients were confirmed by preoperative Color Doppler ultrasound assessments and UGFNA.The injections of isolation fluid were used to protect the surrounding tissue which adjacent to the important structures of the neck before ablation.Post-ablation results were assessed by contrast-enhanced ultrasound.Postoperative follow-up results were reviewed by conventional ultrasound examinations,if necessary,it was checked by contrast-enhanced ultrasound.Thyroid function tests were performed during follow-up period,and serum thyroglobulin were monitored in patients who had cervical recurrences and metastases of PTC during the follow-up period to evaluate the treatment efficacy.Results 1.A total of 53 thyroid nodules were treated by MWA completely.The average volume of the nodules before and after ablation was 11.68±10.16 ml and 6.38±4.78 ml,retrospectively.The volume reduction rates(VRR)at 1,3,6,12,and 18 months after ablation were 0.47±0.34,0.58±0.29,0.72±0.21,0.86±0.12,and 0.92±0.10,respectively.Six(11%)thyroid nodules completely disappeared during follow-up.There was significant difference in VRR among the three nodule types(P < 0.05): VRR% of solid nodules < VRR% of predominant solid nodules < VRR% of predominant cyst nodules.Thesymptoms of all patients were improved significantly after ablation.Thyroid function tests(TSH / FT3 / FT4)were in the normal range at 1,3,6 and 12 months during follow-up,and showed no significant difference when compared with the preoperative thyroid function(p > 0.05).There were no serious complications during and after the procedure.2.A total of 36 nodules of PLA with a single fiber under ultrasound guidance were successfully performed.There were thyroid subcapsular hematoma in 1 case,intraoperative pains in 23 cases,and no neurological,tracheal,esophageal,vascular injuries or skin burns and other serious complications.The volume of benign thyroid nodules was significantly reduced at 1,3,6,and 12 months(P < 0.05),and the signals of blood flow in ultrasound examinations disappeared during follow-up.PTMCs,recurrences and metastases of PTC were significantly disappeared and no regrowth was found during the last follow-up.The thyroid functions of benign cold thyroid nodules and PTMCs patients were in the normal range from preoperative time to postoperative 1 to 3 months.The hyperthyroidism symptom in the patient with autonomously functioning thyroid nodules was disappeared after the secondary laser ablation.3.The average volume of preoperative benign thyroid nodules in RFA was 1.84±1.69 ml and the average volume was0.18±0.25 ml in the last follow-up.The average volume reduction rates(VRR%)at 1,3,6,and 12 months after ablation were 19.22%,58.62%,78.45%,and89.8%,respectively.The volumes were significantly reduced(P < 0.05).The reduction rates of PTMCs at 6 and 12 months follow-up after ablation were66.31±10.72% and 96.75±3.95%,respectively.The thyroid functions were normal in all patients during follow-up.Small local recurrences and metastases of PTC were completely ablated,and the efficacy of short-term clinical follow-up was good.The average volume decreased from 0.23±0.17 ml to0.034±0.032 ml after ablation,and the thyroglobulin levels of four patients were significantly decreased during follow-up.The multiple recurrences and metastases of large lesions of PTC had a better response with the average VRR% > 50%,and the local clinical symptoms were significantly improved.Conclusion 1.Ultrasound-guided percutaneous microwave ablation of large thyroid benign nodules was safe and effective.2.Ultrasound-guided PLA using a single fiber was safe and cost-effectiveness with the methods of one-point ablation,two-point ablation and stratification multiple-points ablation.3.RFA was effective in treatment of benign thyroid nodules and PTMCs,and it could be used as an alternative treatment for the patients who had neck recurrences and metastases of PTC with absent radioiodine uptake and high surgical risk. |
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