A Preliminary Study Of Ultrasound Shear-Wave Elastography In Evaluation Of Lumbar Multifidus Stiffness In Healthy Adults

ObjectiveTo explore the repeatability of ultrasound SWE(shear wave elastography)in evaluating the lumbar multifidus stiffness,to analyze the differences in bilateral LM(lumbar multifidus)stiffness and stiffness change ratio were analyzed,and to evaluate the influencing factors of LM’s Young’s modulus(E)and E’s change ratio in healthy adult in different postures objectively.MethodThis cross-sectional study included twice measurements of Young’s modulus of lumbar multifidus in 64 healthy adults in prone,upright and 90° flexion positions with SWE.Firstly,ICC(intraclass correlation coefficient)was used to test the reliability between the two repeated measurements.Then,Brown-Forsythe test,Kruskal-Wallis test,Mann-Whitney test or T-test were used to analyze the difference of LM Young’s modulus and its E’s change ratio under different activation states within and between groups.Spearman correlation coefficient was used to evaluate the correlation between LM Young’s modulus and its E’s change ratio with gender,age,BMI and activity level.ResultsThe repeatability of evaluating lumbar multifidus with SWE is well.There was no significant difference in LM stiffness and its E’s change between left and right sides of the same individual.In prone position,the Young’s modulus of male LM was lower than that of female LM.The Young’s modulus increased significantly during contraction,and there was no significant difference between male and female characters,but in both active states the change ratio of LM stiffness in male is higher than that in female.The Young’s modulus of LM at rest changed with age and activity level of selfassessment,and was negatively correlated with age and activity level,but not significantly correlated with BMI.The change ratio of LM stiffness was positively correlated with age and activity level,but not significantly correlated with BMI.The E’s change ratio of LM in upright position is about 2,and that in 90° flexion position is close to 7.ConclusionSWE has good repeatability in evaluating the lumbar multifidus stiffness.There was no significant difference in stiffness and its change ratio of bilateral lumbar multifidus.During the contraction,the Young’s modulus and its change ratio of LM increases significantly,and may change with age,sex and self-reported activity level.The LM stiffness change ratio varied with different contraction strategies.These findings should be accounted for in future comparative clinical studies.