The Application Of Elastic Area Ratio And Strain Rate Ratio In The Differentiation Of Thyroid Nodules

BackgroundIn the past few years,the increasing number of patients with thyroid nodules have been found in clinical work,which has become a research hotspot about the issue of incidence of thyroid cancer,and the function of application of high frequency ultrasound scanner to the screening of thyroid disease and diagnosis has been increasingly obvious.According to the research of Cooper DS and other foreign scholars,it is found that the detection rate of thyroid nodules is as high as 67%,especially common in women,which accounts for 5%～10%for the proportion of malignant nodules found in the detected nodules and there is a increasing trend of year by year.Therefore,the clinical detection of thyroid cancer is particularly important,and it is essential that thyroid cancer detected and made a definite diagnosis as early as possible as well as taken active treatment measures in order to achieve the effect of improving patients’ condition significantly.Now,ultrasonic testing(ultrasonography,USG)has become a routine detection of thyroid nodules,which mainly relies on the diagnosis of the conventional two-dimensional ultrasound and color Doppler ultrasound,but the sensitivity and specificity would not be high if we purely made a malignant and benign for thyroid nodules by two-dimensional ultrasound,which should result in the identification index only from the focal boundary state,the degree of calcification,echo,aspect ratio and so on.In recent years,with the rapid development of ultrasound detection technology and the increasing clinical acceptance of ultrasound elastography,new methods have been added to identify the benign and malignant thyroid nodules.Elastic imaging is the process of feedback on the information about the elastic state of tissue,which can be regarded as a key index to determine the attributes of lesions.The biological characteristics of tissue elasticity and lesion is closely related to the organization,usually elastic characteristics under pathological conditions will change,such as changes of malignant lesions often caused by elastic properties,the microstructure and hardness increased,thereby increasing tissue elasticity,and this is because that the lesions with high hardness generally exist in malignant lesions and these lesions also exist in infiltrating growth with characteristics of the edge of a star or crab like,and in the vicinity of structure adhesion.Ultrasound elastography(ultrasound elastography UE)provides images of tissue hardness and shows the hardness of various tissuesin the form of image,which clearly reflects the different hardness of the organization so as to judge the malignant and benign as the basis,and the technology has become a new method for diagnosis of benign and malignant thyroid nodules.The application of thyroid ultrasound elastography in accordance with different incentive methods can be divided into the following categories:acoustic radiation force impulse(acoustic radiation force impulse,ARFI),pressure(compression elastography,CE elastography)and ultrasonic shear wave imaging(supersonic shear-wave imaging,SSI),and they have been the most elastic imaging technologies commonly used and have achieved a good application in the diagnosis of thyroid disease.CE imaging technology is implemented in a static manner,or it can be called strain elastography(SE),appearing earliest in the clinical application about this imaging technique.The compression process of CE technology is achieved by hand-held probe and brings about the longitudinal compression sense to the corresponding tissue region from the probe axis,causing tissue deformation,and the deformation state of ultrasonic monitoring and tracking,using the relative analysis method of deformation in the composite tissue before compression and compression obtained after the echo signal,and calculating the strain or displacement of organization and encoding it for the desired image by pseudo color or gray scale.The principle of ARFI imaging is to test the stiffness and elasticity of a particular tissue around by means of sound radiation,which belongs to dynamic elastography.ARFI using ultrasonic focusing probe is by emitting low frequency acoustic pulses to test the tissue of interest,and when the test area of the organization receives the incentive of its internal micro deformation while generating shear wave toward the periphery spread in all directions,or degree of shear wave propagation analysis of deformation of the test section and the echo signal is extracted to the organization(shear wave velocity,SWV),so as to gain a sense of elastic interest organization feedback information.ARFI technology includes vtq(virtual touch tissue quantification,VTQ)and virtual touch tissue imaging(virtual touch tissue imaging,VTI)of the two technology,the VTI technology on Microstructure and formation of longitudinal compression displacement information feedback,and then through the performance of gray-scale image encoding tissue hardness and elastic state.The darker area represents the hardness of the tissue here,and the brightness of the region indicates that the hardness of the tissue here is low.VTQ technology is to collect the transverse deformation information of tissue firstly,then calculate the shear wave velocity that can be obtained by hardness and elastic tissue,which is also known as point shear wave imaging technology(point shear wave elastography,point SWE).Generally speaking,shear wave has a relatively fast propagation rate in higher hardness tissues,otherwise,when the tissue hardness is lower,the propagation rate is smaller.This research mainly uses the VTI technology in the elastic area ratio(elastic area radio,EAR)and strain rate ratio(strain rate SR)for quantitative evaluation of thyroid nodules,and the two applications are helpful to differential diagnosis of benign and malignant thyroid nodules,which can significantly improve the value of ultrasonography in diagnosis of thyroid nodules.However,the thyroid nodules is associated with diffuse lesions because of the basic diseases,which leads to parenchymal tissue changes and affects the clinical diagnosis.The above two kinds of ultrasound elastography currently comorbid with or without diffuse lesions of thyroid nodules is lack of uniform standards,and a comparative study of two of the value of elastography in the diagnosis of thyroid nodules in the literature is lack of study.Objectives1.This research aims to investigate the elasticity of thyroid nodules in patients combied with or without diffuse lesions,and to provide evidence for the differential diagnosis of benign and malignant thyroid nodules;2.This research aims to compare the diagnostic value of acoustic contrast tissue imaging(VTI),elastic area ratio,and strain rate ratio for thyroid nodules combined with or without diffuse lesions.Materials and Methods1.clinical data:To select 72 cases(84 nodules)of patients suspected thyroid nodules who were treated at our hospital from March to December in 2014,which are confirmed by pathological examination.Inclusion criteria:solid or solid nodules;the diameter of nodules is 5-40mm;and there are no gross calcification and large liquefaction areas in the nodules.There are 20 males and 52 females.The age was 32～65 years.Confirmed by pathological examination with diffuse lesions(39 nodules with Hashimoto’s thyroiditis,13 nodular goiter,26),including 17 benign and 22 malignant lesions;not with diffuse nodules in 45,including 15 benign and 30 malignant cases.2.instruments and methodsThe patients are examined with conventional ultrasound and an ultrasonic diagnostic instrument equipped with VTI software.Germany SIEMENS S2000 ultrasonic diagnostic instrument,equipped with VTI software,select 9L4 probe,probe frequency 4.09.0MHz.With the patient in the supine position,fully exposed the neck,asking the calm breathing,adjusting the gain,focus and depth to the appropriate conditions,the ultrasonographic features of thyroid nodules were observed and recorded,in "EI" mode,sampling frame focus range 2-3 times.Patients are required to hold breath,holding the probe contact location,when the mass fraction is less than 60,store images on VTI imaging using Image J software with image sketch and recording nodules on conventional two-dimensional ultrasound imaging and VTI in the area.The other pulmonary nodules in the same depth of thyroid tissue as the reference strain rate is marked nodule A,with the depth of the same size of normal thyroid tissue strain rate of each nodule marked B,5 frames from the trusted image,to take the average.EAR= showed a nodule area/conventional ultrasound showed the area of the nodule;SR = B/A.3.statistical analysisUsing SPSS19.0 statistical software.The measurement data is expressed by X士s,and t test is compratively used.X2 test is used to compare count data.Receiver operating characteristic(ROC)curve is drawn to evaluate the diagnostic efficacy of EAR and SR on thyroid nodules.The area under the curve(area,under,the,curve,AUC)is compared with Z test.The difference of P<0.05 is statistically significant.Results1.Diagonosis results of conventional ultrasound,EAR,SR for thyroid nodules:1.1 Conventional ultrasonography in diagnosis of benign and malignant lesions with diffuse nodules the sensitivity,specificity and accuracy are 66.7%,88.3%,77.8%,EAR are 73.3%,90%,84.4%,SR are 80%,86.7%,84.4%.The sensitivity,specificity and accuracy of EAR and SR are compared with those of conventional ultrasound.P(average)<0.05,EAR specificity,sensitivity is compared with SR,P(average)<0.05,and the accuracy rate of the two is P>0.05.1.2 Conventional ultrasound for diagnosis of benign and malignant lesions with diffuse nodules the sensitivity,specificity and accuracy are 70.6%,77.3%,74.4%,EAR are 82.4%,81.8%,82.1%,SR are 76.5%,86.4%,82.1%.The sensitivity,specificity and accuracy of EAR and SR are compared with those of conventional ultrasound.P(average)<0.05,EAR specificity,sensitivity is compared with SR,P(average)<0.05,and the accuracy rate of the two is P>0.05.1.3 The specificity and accuracy of conventional ultrasound,EAR and SR in the diagnosis of benign and malignant nodules of combined and non diffuse lesions are P,(average)<0.05.Comparison of EAR and SR in 2.benign and malignant nodules2.1 In the diffuse lesion group,the benign nodule EAR is significantly lower than the malignant nodule {(0.92 + 0.23)vs(1.33 + 0.13),P<0.05} and benign nodule SR is significantly lower than the malignant nodule {(3.05 + 1.17)vs(4.76 + 1.06),P<0.05};2.2 EAR With diffuse lesion group is obviously lower than that in benign nodules EAR with malignant nodules {(0.93 + 0.21)vs(1.30 + 0.17),P<0.05} SR is obviously lower than that in benign nodules,malignant nodules {(3.77 + 2.40)vs(5.35+ 1.57),P<0.05}.3.Diagnostic efficacy of EAR and SR in the diagnosis of thyroid nodules and diffuse lesions,with truncated nodules values are 1.06 and 0.89,the area under the curve is 0.877,two of the area under the curve comparison,P>0.05.The cutoff values of SR for the diagnosis of nodules with or without diffuse lesions are 3.48 and 3.62,respectively.The area under the curve is 0.869 and 0.772,respectively,and the area under the curve of the two is P>0.05.ConclusionsVTI elastic area ratio and strain rate are more effective than the two for differential diagnosis combined with and without diffuse lesions of benign and malignant thyroid nodules,improving the benign and malignant thyroid nodules ultrasound in differential diagnosis of sensitivity,specificity and accuracy,but the efficacy of differential diagnosis is similar.The differential diagnosis of benign and malignant thyroid nodules with ultrasound elastography provides a new method for clinical diagnosis and shows broad prospects in the clinical diagnosis of thyroid diseases.