Evaluation Of Elasticity Of Achiles Tendon In Normal And Type 2 Diabetes Mellitus By Shear Wave Elastography

ObjectiveTo establish the range of reference values for the elasticity of normal Achilles tendon using shear wave elastography（SWE）,analyze its relationship with different age,and evaluate its values in the diagnosis of Achilles tendon lesions in early diabetes mellitus and diabetes mellitus with microvascular complications.MethodTotally Achilles tendon of 336 healthy volunteers（normal group）,62 patients with early type 2 diabetes mellitus（DM group）,and 42 patients with type 2 diabetes mellitus with microvascular complications（DMMC group）using two-dimensional high-frequency ultrasound and SWE.Healthy volunteers were divided into four age groups according to age:A group（20-30 years old）,B group（31-40 years old）,C group（41-50 years old）,D group（51-60 years old）.Observe the internal echo of the Achilles tendon and the tissue of the Achilles tendon,and measure the E_mean,E_max,SWV_meanean and SWV_max in the middle of the Achilles tendon（2 cm⁶ cm above the junction of the Achilles tendon and the calcaneus）,and analyze the correlation of all measurements and age.The Achilles tendon of DM group and DMMC group were evaluated according to the above methods.30 cases of Achilles tendon collected randomly was esamined by the inter-/intra-operator to analyzed the repeatability and consistency.ResultsCompared with the normal group,the DM group and the DMMC group are more likely to have abnormal signs on the high-frequency ultrasound imaging（P<0.05）.and there was no statistically significant difference in the presence of abnormal signs between the DM group and the DMMC group.The inter-/intra-operator reproducibility of the E_mean,E_max,SWV_mean,SWV_max were good,ICC>0.75,and the inter-operator reproducibility were the highest than intra-operator.The 95%consistency limit width of the E_mean,E_max,SWV_meanean and SWV_maxax of the inter-operator were narrower than that of the intra-operator,indicating that the inter-operator consistency were the highest than intra-operator.In the normal group,The normal Achilles tendon E_mean,E_max,SWV_meanean and SWV_maxax increased along with the age,and the regression equations were:E_mean（kPa）=-0.017x²+3.926x+186.464,R²=0.837;E_max（kPa）=-0.018x²+4.352x+237.179,R²=0.731;SWV_mean（m/s）=-0.0004x²+0.076x+7.885,R²=0.826;SWV_max（m/s）=-0.0005x²+0.079x+8.880,R²=0.680,x:age.Compared with the normal group,the E_mean,E_max,SWV_meanean and SWV_maxax of the DM group and the DMMC group were higher than those of the normal group.But compared with DM group,there was no significant difference in E_mean,E_max,SWV_meanean and SWV_maxax of the DMMC group.conclusion（1）SWE can quantitatively analyze the hardness changes of Achilles tendon tissue,and has good repeatability and consistency.It is an important supplementary examination of conventional two-dimensional ultrasound.（2）Established the the range of reference values for E_mean,E_max,SWV_meanean and SWV_maxax in normal middle Achilles tendon of different ages,and each index was positively correlated with age.The normal value reference range of this study can be used as a reference standard for the normal value of the domestic SWE measurement Achilles tendon.（3）SWE can be used to assess changes in Achilles tendon hardness in diabetic patients,but it is still insufficient to assess the severity of diabetes.