The Value Of Real-time Shear Wave Elastography In Diagnosis Of Dermatomyositis

Objective:In this study,SWE was used to obtain the muscle hardness of dermatomyositis associated injuries,and we measured the value of young's modulus comparing with that of the normal muscle group,so as to evaluate the value of real-time shear wave elastography in the diagnosis of dermatomyositis.Object:From November 2018 to October 2019,a total of 30 cases patients with diagnosis of DM proved by muscle biopsy and pathology that visited the outpatient and inpatient departments of the rheumatology and immunology department of our hospital.There were 30 DM patients,according to Bohan and Peter diagnostic criteria(1975),aged 18 to 60.Among the 30 patients,9 were males and 21 were females whose courses of disease ranged from 3 months to 10 years.The control group consisted of 40 healthy subjects,including 20 males and 20 females,aged 18 to 60.All subjects were informed to be included in the experimental study,who gave informed consent.Methods:1?Subjects in the DM experimental group and the control group received routine ultrasound examination and real-time shear wave elastography(SWE)examination,respectively.In conventional two-dimensional ultrasound patterns,by the examination of both sides of the thigh part section muscle,the priority measure are condition of muscle,continuity muscle echoes of meshy deep fascia connective tissue,echo intensity,interior and peripheral blood flow feature observed by color doppler.Then we restart SWE model,and obtain its young's modulus maximum(Max value of elasticity,Emax)and the average(Mean value of elasticity,Emean),and storing the relevant images.2?According to the above results,the difference of young's modulus Emax and Emean between the two groups was statistically analyzed,and the receiver operating characteristic curve(ROC)and area under the curve(AUC)were drawn to determine the optimal SWE best value for DM diagnosis that sensitivity and specificity are calculated based on.Results:1?Results of ultrasound examination: DM was characterized by the absence of satiation in the tested muscle group(especially in patients with a long course of disease with recurrent attacks),increased short linear intense light spots or enhanced diffuse echo,and occurred discontinuous or discontinuous meshy echo.In the control group,the muscles were plump,with good saturation,clear and continuous muscle bundle structure and even echo.The blood flow in the muscle tissue was slightly decreased or hardly abnormality was observed.2?Comparison of SWE young's modulus between the two groups: the young's modulus Emax and Emean in the DM group were both greater than those in the normal control group,and the differences were statistically significant(P<0.05),indicating that the muscle elasticity of the DM patients which muscles were stiffer,was worse than that of the normal control group.3?SWE imaging technique measures the efficacy of young's modulus value in diagnosing DM.The SWE technique measures the area below the ROC curve of Emax in diagnosing DM lesions was about 0.796 by testing the young's modulus value(95% confidence interval: 0.707-0.884).The sensitivity and specificity of the diagnosis of DM with the cut-off value of 24.05 kPa were 77.50% and 83.30%.While the area under the ROC curve of the diagnosis of DM with young's modulus Emean was about 0.856(95% confidence interval 0.776-0.935)and that with 19.00 kPa as cut-off value were 76.70% and 90.00% respectively.Conclusions:1?Real-time shear wave elastography(SWE)technology can be used for quantitative analysis of young's modulus value of muscle elasticity,offer assistance for diagnosis of muscle hardness,have certain value for the diagnosis of dermatomyositis,and provide a new method and idea for the early diagnosis of this disease.Moreover,ultrasound examination is simpler,more convenient,flexible and repeatable that can dynamically observe and test the elastic value of muscles than other imaging examinations such as MRI.2?Conventional gry-scale ultrasound combined with real-time shear wave elastography technology can help diagnose dermatomyositis,perfect the diagnostic information,and select the appropriate clinical muscle to do muscle biopsy and electromyography(EMG)for higher positive rate.