Clinical Study Of Elastic Ultrasound In The Diagnosis Of Non-calcified And Calcified Nodules Of The Thyroid Gland

Chapter 1 The diagnostic performances of strain elastography(SE)and shear wave elastography(SWE)for thyroid non-calcified nodulesObjective The purpose of this study was to investigate the performance of strain elastography(SE)and shear-wave elastography(SWE)in differentiating benign and malignant thyroid non-calcified nodules.Methods A total of 201 thyroid non-calcified nodules(mean diameter,20.1±11.2mm)in 195 patients(mean age,50±13yr)were studied,and they were examined by conventional ultrasound(US),SE and SWE.All images of US,SE and SWE for thyroid nodules were acquired with the same US instrument,including conventional SE,acoustic radiation force impulse(ARFI)SE and point shear-wave speed(pSWS)et al.Receiver operating characteristic(ROC)curve was plotted to evaluate the diagnostic performance.Univariate and multivariate logistic regression analyses were performed to assess 8 possible predictors of malignancy for non-calcified thyroid nodules.Multivariable models at US,SE,SWE and US+SE+SWE for risk of malignancy were analyzed with multivariate regression analysis and ROC curve.Significance was assigned for two-tailed P value<0.05.Results There were 156 benign and 45 malignant non-calcified nodules proven by pathology.Areas under receiver operating characteristic curve(AUROC)of all the US features for non-calcified thyroid nodules were smaller than 0.8,while AUROC of conventional SE score,ARFI SE grade,SWS of nodule and SWS ratio were 0.826,0.848,0.860 and 0.845 respectively.Multivariate analysis showed only marked hypoechogenicity at US was a significant predictor for non-calcified malignant nodules with Odds ratio(OR)=26.13(95%CI:3.50,194.93),and while ORs of conventional SE score>3,ARFI SE grade>3,SWS of nodule>2.49m/s and SWV Ratio>1.22 at SE and SWE were 26.113(95%CI:3.498,194.932),3.876(95%CI:1.241,12.106),4.234(95%CI:1.345,13.329),10.641(95%CI:2.990,37.864)and 4.084(95%CI:1.213,13.756)respectively.The analysis of multivariable models displayed AUROCs of US+SE+SWE was the highest with 0.936(95%Cl:0.887,0.985),and followed by SWE(AUROC:0.889;95%CI:0.823,0.955),and the poorest was US(AUROC:0.727;95%Cl,0.635-0.819).Conclusion SE and SWE are promising for diagnosis of non-calcified thyroid nodules,with higher diagnostic performance than US.When US,SE and SWE combined for non-calcified thyroid nodules,they have higher diagnostic value.Chapter 2 The research of pSWS in diagnosing thyroid different-calificated nodules using single and multiple calcification-specific cutoff valuesObjective To investigate the effect of calcifications in thyroid nodules associated with point shear wave speed(pSWS)of nodules,and estimate the diagnostic performances between single and individual cutoff values for thyroid nodules with different calcifications.Materials and Methods This retrospective study was approved by the Ethical Committee and the requirement to obtain informed consent was waived.A total of 517 thyroid nodules in 498 patients included 177 non-calcified,159 micro-calcified and 181 macro-calcified nodules from January 2014 to November 2015.Ultrasound(US),strain elastography(SE)and pSWS were performed with the Siemens 2000 Ultrasound instrument.The single and individual cutoff values of pSWS for predicting malignancy were determined yielding the maximum Youden index(YI),90%sensitivity and 90%specificity,in non-calcification,micro-calcification and macro-calcification groups respectively.The diagnostic performances between single and individual cutoff values for thyroid nodules were evaluated by receiver operating characteristic(ROC)curve and Chi-square test.A two-tailed P value<0.05 was statistically significant.Results There were 346 benign and 171 malignant thyroid nodules proven by pathology.The average pSWS of nodules were 2.60± 1.49 m/s,3.27±1.85 m/s and 3.68±2.26 m/s respectively in non-calcification,micro-calcification and macro-calcification groups(p<0.001).The diagnostic cutoff values of pSWS of nodule were 2.72 m/s,2.42 m/s,2.88 m/s and 3.59 m/s for the maximum YI,respectively in the whole,non-calcification,micro-calcification and macro-calcification groups(p =0.03).The areas under of receiver operating characteristics curve(AUROC)in the whole group applying individual cutoff values compared to single cutoff values were 0.859(95%CI,0.826-0.888)vs 0.816(95%CI,0.780-0.848)(p =0.011),that in non-calcification group 0.906(95%CI,0.853-0.945)vs 0.799(95%CI,0.732-0.855)(p =0.004),that in micro-calcification group 0.871(95%CI,0.809-0.919)vs 0.859(95%CI,0.795-0.909)(p =0.559),and that in macro-calcification group 0.805(95%CI,0.740-0.860)vs 0.698(95%CI,0.625-0.764)(p<0.001).Conclusion The average pSWS of thyroid nodules were increased orderly in non-calcification,micro-calcification and macro-calcification groups,and their optimal cutoff values should be individual.The diagnostic performances of pSWS for thyroid nodules applying individual cutoff values were superior to that applying single cutoff value.