Application Of Real-time Tissue Elastography In Differential Diagnosis Of Benign And Malignant Thyroid Nodules

Objective:To investigate the application value of real-time tissue elastography in the differential diagnosis of benign and malignant thyroid nodules.Methods:89 cases(159 thyroid nodules)which completed surgical pathology in the fifth affiliated hospital of kunming medical university from october 2018 to february 2020 were selected.The ES and SR value of each nodule were measured pre-operatively using the ES method and SR method.The ROI A of SR method was selected thyroid nodule tissues,while ROI B was selected para-nodule thyroid tissues and cross-sectional muscle tissue of ipsilateral sternocleidomastoid muscle,ROI A is at the same level with ROI B,and its size and shape are basically the same.159 thyroid nodules were divided into the following subgroups:(1)According to the pathological results,the nodules were divided into benign group(n=83)and malignant group(n=76).(2)According to whether the thyroid tissues which outside the nodules are combined with HT,the nodules are divided into the nodules with HT group(n=66)and the nodules with normal thyroid tissues group(n=93).(3)According to the HT ultrasound image,the nodule combined with HT group was further divided into the localized hypoechoic group(n=34)and the diffuse grid echo group(n=32).(4)According to calcification and benign or malignant nodules,the nodules were divided into benign nodules with calcification group(n=12),benign nodules without calcification group(n=71),malignant nodules with calcification group(n=44)and malignant nodules without calcification group(n=32).In order to explore the effect of HT and thyroid nodules,43 cases with HT diagnosed in the Fifth Affiliated Hospital of Kunming Medical University from October 2018 to February 2020 were selected as Observe(HT)group,and 46 volunteers with normal physical examination were selected as Control(normal)group in the same period.The SR value(select normal thyroid tissue and HT thyroid tissue as ROI A,select Cross-sectional muscle tissue of ipsilateral sternocleidomastoid muscle as ROI B)were measured using the SR method of RTE.The ES scores of the above groups were tested by ?2 test,and the SR values of each group were tested by t test.When P<0.05,the difference was statistically significant;when P<0.01,the difference was statistically significant.The ROC for the diagnosis of benign and malignant nodules were drawn by ES method and SR method(select thyroid nodule tissue as ROI A,select para-nodule thyroid tissues and ipsilateral sternocleidomastoid muscle as ROI B).the area under each curve was calculated,The maximum index was taken to determine the best diagnostic boundary point of each curve,and its sensitivity and specificity were calculated.The NRI of Z test was used to compare the diagnostic efficiency of RTE methods.The factors that may affect the SR value of each group were analyzed by single factor correlation analysis,and the correlation coefficient was calculated.Results:(1)The ES and SR value(select thyroid tissue as ROI A,select para-nodule thyroid tissues and cross-sectional muscle tissue of ipsilateral sternocleidomastoid muscle as ROI B)of the malignant nodule were all greater than that of the benign nodule,and the difference was statistically significant(P<0.01).The maximum index of the three ROC curves were 0.651,0.787 and 0.773,the best diagnostic cutoff were 4 points,2.45 and 2.70,the area under the curve was 0.896,0.942 and 0.938,the sensitivity was 80.5%,90.2%and 92.7%,the specificity was 84.6%,88.5%and 84.6%.(2)There was no statistically significant difference(P>0.05)between the left and right SR(selected thyroid tissue as ROI A,select the ipsilateral sternocleidomastoid muscle cross-sectional muscle tissue as ROI B).The control(normal)group,localized hypoechoic group HT,diffuse hypoechoic group HT thyroid SR value(ROI A selected normal and HT thyroid tissue,ROI B selected ipsilateral sternocleidomastoid muscle cross-sectional muscle tissue)increased step by step,They were 1.12±0.13,1.30±0.18,1.96±0.45,and there were all significant differences among the three groups(P<0.01).(3)Malignant nodules SR values(selected thyroid nodules as ROI A,select the ipsilateral sternocleidomastoid muscle cross-sectional muscle tissue as ROI B)of the nodules with localized hypoechoic HT group and the nodules with diffuse hypoechoic HT group were higher than in benign nodules,the differences were statistically significant(P<0.05).The maximum index of localized hypoechoic HT group(select para-nodule thyroid tissues and Cross-sectional muscle tissue of ipsilateral sternocleidomastoid muscle as ROI B)ROC curves were 0.639 and 0.756,the best diagnostic cutoff were 1.88 and 2.73,the area under the curve was 0.875 and 0.906,the sensitivity was 88.9%and 94.4%,the specificity was 75%and 81.2%.The maximum index of diffuse hypoechoic HT group(select para-nodule thyroid tissues and cross-sectional muscle tissue of ipsilateral sternocleidomastoid muscle as ROI B)ROC were 0.498 and 0.682,the best diagnostic cutoff were 1.8 and 2.9,the area under the curve was 0.841 and 0.922,the sensitivity was 76.5%and 88.2%,the specificity was 73.3%and 80.0%.(4)When the thyroid tissue outside the nodule is normal echo:The best diagnostic cut-off point of ROC curve for the diagnosis of benign and malignant nodules by SR method(select para-nodule thyroid tissues as ROI B)compared with the ES method,the positive improvement of the NRI is 13.6%,and the difference is statistically significant(Z=2.23,P=0.026);There was no significant difference in NRI between SR(select para-nodule thyroid tissues and cross-sectional muscle tissue of ipsilateral sternocleidomastoid muscle as ROI B)(Z=0.20,P>0.05);When the thyroid tissue outside the nodule with HT:The NRI values between SR(select para-nodule thyroid tissues and cross-sectional muscle tissue of ipsilateral sternocleidomastoid muscle as ROI B)at the nodules with localized hypoechoic HT group and the nodules with diffuse grid HT group were positively improved,the values were 11.7%and 18.4%,differences were statistically significant(P<0.05).(5)When the paranodular thyroid tissue was selected by ROI B of SR method,the paranodular thyroid tissue was normal thyroid tissue,localized hypoechoic HT and diffuse hypoechoic HT,respectively,The NRI was gradually decreased,that is,the diagnostic efficiency decreased gradually,and there was statistical significance in all groups(P<0.05).When the cross-sectional muscle tissue of the same level sternocleidomastoid muscle was selected by ROI B of SR method,there was no significant difference in NRI between the normal thyroid tissue,localized hypoechoic HT and diffuse hypoechoic HT(P>0.05).(6)No matter the thyroid tissue which outside the nodule is normal echo or thyroid lesion with HT,the SR(select thyroid tissue as ROI A,select para-nodule thyroid tissues as ROI B)of the nodule with microcalcification group was higher than the nodular non-calcification group,and the difference was statistically significant(P<0.05).(7)When thyroid tissue which outside the nodule is normal echo,the SR(select para-nodule thyroid tissues as ROI B)is positively correlated with the maximum diameter of nodule,aspect ratio and microcalcification with nodule,respectively,the correlation coefficient r is 0.36,0.56 and 0.61(P<0.01).The SR(select cross-sectional muscle tissue of ipsilateral sternocleidomastoid muscle as ROI B)is positively correlated with the maximum diameter of nodule,aspect ratio and microcalcification with nodule,respectively,the correlation coefficient r is 0.34,0.57 and 0.61(P<0.01).When the thyroid tissue which outside the nodule is HT lesion:the SR(select para-nodule thyroid tissues as ROI B)is positively correlated with the maximum diameter of nodule,aspect ratio and microcalcification with nodule,respectively,the correlation coefficient r is 0.32,0.48 and 0.49(P<0.01).The SR(select cross-sectional muscle tissue of ipsilateral sternocleidomastoid muscle as ROI B)is positively correlated with the maximum diameter of nodule,aspect ratio and microcalcification with nodule,respectively,the correlation coefficient r is 0.30,0.51 and 0.50(P<0.01).No matter the thyroid tissue which outside the nodule is normal echo or thyroid lesion with HT,the SR(select para-nodule thyroid tissues and Cross-sectional muscle tissue of ipsilateral sternocleidomastoid muscle as ROI B)had no correlation with sex,age and blood flow grade(P>0.05).Conclusions:(1)Both ES method and SR method of RTE technique can be used as effective indexes for the differential diagnosis of benign and malignant thyroid nodules,and the diagnostic efficacy of SR method is better than that of ES method in the differential diagnosis of benign and malignant thyroid nodules.(2)When the cross-sectional muscle tissue of the ipsilateral sternocleidomastoid muscle was selected as ROI B,The SR measured value of the normal thyroid group,localized hypoechoic HT group and diffuse grid HT group was increased gradually.On this basis,the measured value of SR method can affect the diagnostic efficiency of benign and malignant thyroid nodules.(4)When thyroid tissues outside thyroid nodules with HT lesions,if paranodular thyroid tissues are selected as ROI B,the diagnostic efficacy of differential diagnosis of benign and malignant thyroid nodules can gradually decrease with the increase of the scope and severity of HT lesions.If cross-sectional muscle tissue of the ipsilateral sternocleidomastoid muscle was selected as ROI B,the diagnostic efficacy of differential diagnosis of benign and malignant thyroid nodules has nothing to do with the extent and degree of HT lesions.When thyroid nodule with HT,the SR measured value selected cross-sectional muscle tissue of the ipsilateral sternocleidomastoid muscle as ROI B for differentiating diagnosis of benign and malignant thyroid nodules was the preferred method.(5)Microcalcification,aspect ratio and maximum diameter of thyroid nodules are the influencing factors of SR in the differential diagnosis of benign and malignant thyroid nodules.