The University of Queensland, School of Health and Rehabilitation Sciences, Brisbane, Australia.
The University of Queensland, School of Health and Rehabilitation Sciences, Brisbane, Australia; University of Nantes, Laboratory "Movement, Interactions, Performance", Nantes, France; Institut Universitaire de France (IUF), Paris, France.
J Electromyogr Kinesiol. 2021 Feb;56:102505. doi: 10.1016/j.jelekin.2020.102505. Epub 2020 Nov 19.
Shear wave elastography (SWE) estimates shear modulus in muscle. This is interpreted as an index of muscle stiffness, but depends on muscle characteristics. This study evaluated relationship between shear modulus and myoelectric activity of lumbar multifidus and longissimus muscles to assess its validity. Intramuscular electromyography (EMG) of multifidus (deep [DM], superficial [SM] fibres) at L4/5, longissimus [LG] at L2, were recorded in nine healthy participants. Participants performed isometric trunk extension in side-lying from 0 to 30% maximal voluntary contraction (MVC) with EMG amplitude feedback. Using SWE, two regions of interest (ROI) were investigated in each muscle. Generally, shear modulus was moderately correlated with root mean squared (RMS) EMG (r = 0.50-0.78). Univariate and multiple regression analyses showed ultrasound/SWE features of 'B-mode quality' (24.5%), '%Void pixels' (17.9%) and 'Connective tissue' (16.2%) explained most variation in the shear modulus/EMG relationship. Regression prediction scores generated using imaging features were correlated with r-coefficients of shear modulus/EMG relationship. When analysis was restricted to high quality data (i.e., regression prediction score above an a priori defined threshold), the shear modulus/EMG relationship increased to r = 0.70-0.96. Although a linear relationship between shear modulus/EMG was confirmed, supporting validity of SWE measures in anatomically distinct back muscles, this depends on image quality.
剪切波弹性成像（SWE）估计肌肉的剪切模量。这被解释为肌肉硬度的指标，但取决于肌肉的特性。本研究评估了腰椎多裂肌和最长肌的剪切模量与肌电活动之间的关系，以评估其有效性。在 9 名健康参与者中，记录了 L4/5 多裂肌（深部[DM]、表浅[SM]纤维）和 L2 最长肌的肌内肌电图（EMG）。参与者在侧卧位进行等长躯干伸展，从 0 到 30%最大自主收缩（MVC），并带有肌电振幅反馈。使用 SWE，在每个肌肉中研究了两个感兴趣区域（ROI）。一般来说，剪切模量与均方根（RMS）EMG 呈中度相关（r=0.50-0.78）。单变量和多元回归分析表明，超声/SWE 的“B 模式质量”（24.5%）、“空像素百分比”（17.9%）和“结缔组织”（16.2%）特征解释了剪切模量/EMG 关系中大部分的变化。使用成像特征生成的回归预测分数与剪切模量/EMG 关系的 r 系数相关。当分析仅限于高质量数据（即，回归预测分数高于事先定义的阈值）时，剪切模量/EMG 关系增加到 r=0.70-0.96。尽管证实了剪切模量/EMG 之间存在线性关系，支持 SWE 在解剖上不同的背部肌肉中的测量有效性，但这取决于图像质量。
