An ex-vivo validation of the modulus-length framework to characterize passive elastic properties of skeletal muscle

• Published in: Ultrasonics 2023-03, Vol.129, p.106904-106904, Article 106904
• Main Authors: Deng, Miaoqin, Zhou, Liying, Chen, Zengtong, Yuan, Guojian, Zhou, Yongjin, Xiao, Yang
• Format: Article
• Language: English
• Subjects: Animals; Cattle; Chickens; Dynamic shear wave elastography; Elastic Modulus; Elasticity Imaging Techniques - methods; Humans; Modulus-length framework; Muscle, Skeletal - diagnostic imaging; Passive elastic properties; Reproducibility of Results; Skeletal muscle
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2022.106904

•A modulus-length framework to investigate sensitive dynamic parameters of muscle passive elastic properties is validated in four groups of ex-vivo muscle samples (young and old chickens, pork, and beef).•The parameters (k1 and k2) exhibit different value range for 4 groups of muscle samples (including 16 gastrocnemius muscles of Sanhuang chickens and old hens, 15 beef ham muscles and 16 pork tenderloin muscles. The passive elastic properties of skeletal muscles are related closely to muscle extensibility and flexibility. Recently, a single probe setup has been reported that measures the passive elastic properties of muscles in vivo. This uses a modulus-length framework to investigate sensitive dynamic parameters, termed as passive elastic coefficient k, slack length l0, and slack shear modulus G0 to quantify the passive elastic properties of human muscle. In particular, the parameter k calculated based on this framework reflects the change rate of the local shear modulus with respect to the muscle length, which remains constant during the entire passive stretching process. In this report, the modulus-length framework was validated in four groups of ex-vivo muscle samples (young and old chickens, pork, and beef). All the muscle samples were stretched mechanically whilst muscle length was monitored and recorded with simultaneous measurement of dynamic shear wave elastography (SWE). Agreement analyses using Bland-Altman diagrams and intraclass correlation coefficients (ICC) were then performed on coefficient k values obtained by mechanical stretching (k1) and real-time ultrasound imaging methods (k2). Bland-Altman diagrams show that the majority of the points lie within the 95 % LoA ([-1.87, 2.29]; p = 0.276) and the level of reliability was “good” to “excellent” based on the ICC results (ICC, 0.904; 95 % confidence interval, 0.813–0.953). This indicated that the ultrasound and mechanical methods produced very similar results. Meanwhile, the range of the coefficient k values in four muscle types and groups was significantly different (p