The Application Value Of Real-time Shear Wave Elastography To Evaluate Skeletal Muscle Elasticity In COPD Patients

Objectives:To apply the real-time shear wave elastography technique to measure the stiffness of respiratory and extremity muscles in COPD patients,and to explore the correlation between clinical data and muscle ultrasound parameters in COPD patients,and to evaluate the application value of SWE in COPD disease estimation.Methods:1.73 patients with stable COPD who attended our hospital from December 2021 to December 2022 were selected,and 69 healthy people who came to the hospital for physical examination were selected.All subjects underwent pulmonary function tests.The COPD group was divided into 40 people in the mild to moderate group and 33 people in the severe group according to the results of pulmonary function tests.2.Gender,age,body mass index(BMI),6-minute walk test(6MWT)distance,and fat-free mass(FFM)of the subjects were recorded.3.High frequency ultrasound was used to measure respiratory muscle and rectus femoris muscle thickness,diaphragm mobility,and rectus femoris muscle cross-sectional area.The SWE technique was used to measure respiratory muscle and extremity muscle stiffness.Statistical analysis of the collected parameters was performed.Results:1.Comparison of general information.There were no statistically significant differences in the comparison of gender,age,and BMI between the COPD and control groups(P > 0.05).There were statistically significant differences in FEV1(%predicted),6MWT,and FFMI comparisons between the two groups(P < 0.05).2.Comparison of ultrasound parameters of the left and right limb muscles in the COPD and control groups.There was no statistically significant difference between the left and right side ultrasound parameters of the limb muscles in the COPD group and the control group(P > 0.05).3.Comparison of muscle ultrasound parameters between COPD and control groups.Both intercostal muscle and diaphragm in the COPD group were thinner,the rate of thickening dicreased,the stiffiness increased,the diaphragm mobility increased(P< 0.05).The rectus femoris muscle were thinner,cross-sectional area decreased,and lower limb muscle groups stiffness decreased(P < 0.05);the difference in biceps stiffness between the two groups was not statistically significant(P > 0.05).4.Correlation analysis of muscle ultrasound parameters and clinical data in COPD group.(1)Ultrasound parameters of intercostal muscles.Intercostal muscle thickness at the end of inspiration,intercostal muscle thickening rate and were positively correlated with FEV1(%predicted)(P < 0.05).Intercostal muscle stiffness was negatively correlated with FEV1(%predicted)and FFMI(P <0.05).(2)Diaphragm ultrasound parameters.Diaphragm thickness,thickening rate,and mobility were positively correlated with FEV1(%predicted)(P < 0.05).Diaphragm stiffness was negatively correlated with FEV1(%predicted)(P < 0.05).Diaphragm thickness at the end of inspiration was positively correlated with6MWT(P < 0.05).Diaphragm stiffness was negatively correlated with 6MWT and FFMI(P < 0.05).Diaphragm stiffness was negatively correlated with FFMI(P >0.05).(3)Lower limb muscle parameters.Lower extremity muscle group stiffness,rectus femoris thickness and cross-sectional area were positively correlated with FEV1(%predicted)and 6MWT(P< 0.05).Biceps stiffness were not correlated with FEV1(%predicted)(P >0.05).Lower limb muscle group stiffness and rectus femoris cross-sectional area were positively correlated with FFMI(P < 0.05).5.ROC curve of respiratory and extremity muscle stiffness predicting severe COPD in the COPD group:Intercostal muscle stiffiness,anterior tibial stiffiness,gastrocnemius stiffiness,and biceps muscle stiffness did not have predictive value(P > 0.05).The diaphragm stiffness,rectus femoris stiffness,medial femoral muscle stiffness,lateral femoral muscle stiffness,and the combined model of quadriceps stiffness can predict severe COPD(P < 0.05).The highest sensitivity and specificity for predicting severe COPD was the combined quadriceps prediction model,and the highest sensitivity and specificity for independent prediction was VMswe,followed by VLswe,RFswe,and finally Dswe.Conclusions:SWE can identify changes in skeletal muscle stiffness earlier,and skeletal muscle stiffness is significantly correlated with clinical characteristics,which is a potential indicator of clinical characteristics of COPD patients.SWE technique has predictive value in the severity of COPD patients,which provides a basis for early diagnosis,treatment guidance,and improvement of patients’ prognosis.