Background

Shear wave elastography can measure shear wave speed in muscles, which is used to estimate shear modulus. Normative values and standardized methodology are needed for children. Study aims were to: estimate shear modulus behavior of lower limb muscles of typically developing children; and establish a profile of reference data and recommendations for clinical assessment.

Methods

Forty-one typically developing children (mean 9.7 y, SD 1.9 y) completed assessment of resting shear modulus of rectus femoris, biceps femoris, gastrocnemius lateralis and tibialis anterior at short and long lengths using shear wave elastography. Effects of muscle length, age, sex and BMI were examined. Then, our data and data from a scoping review for typical individuals were collated according to Net-Longitudinal Tension Angle (net proximal and distal joint angles).

Findings

Shear modulus was: higher at long versus short muscle lengths for all four muscles (P < 0.001); correlated with increasing age for tibialis anterior at short (r = 0.39) and long lengths (r = 0.42) (both P = 0.01); but not related to sex or BMI. Shear modulus: tended to increase with increasing Net-Longitudinal Tension Angle for 18 lower limb muscles; and was higher for children than adults for some muscles (e.g. tibialis anterior and gastrocnemius lateralis, both P < 0.001).

Interpretation

In typically developing children, shear modulus of lower limb muscles increases with increasing Net-Longitudinal Tension Angle. Recommendations enable comparison of values across different test positions and populations. Some relation between shear modulus and age was identified, but more research is needed.

中文翻译：

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典型发育儿童下肢肌肉剪切模量的参考数据概况

背景

剪切波弹性成像可以测量肌肉中的剪切波速度，用于估计剪切模量。儿童需要规范的价值观和标准化的方法。研究目的是：估计典型发育儿童下肢肌肉的剪切模量行为；并建立参考数据和临床评估建议的概况。

方法

41 名典型发育儿童（平均 9.7 岁，SD 1.9 岁）使用剪切波弹性成像完成了股直肌、股二头肌、腓肠外肌和胫前肌短长和长长的静息剪切模量评估。检查了肌肉长度、年龄、性别和 BMI 的影响。然后，根据净纵向张力角（净近端和远端关节角）对我们的数据和对典型个体进行范围审查的数据进行整理。

发现

剪切模量是：所有四块肌肉的长肌肉长度与短肌肉长度相比更高（P  < 0.001）；与胫骨前肌在短 ( r  = 0.39) 和长 ( r  = 0.42) (两者P  = 0.01) 的年龄增长相关；但与性别或 BMI 无关。剪切模量：随着18条下肢肌肉的净纵向张力角的增加，有增加的趋势；儿童的某些肌肉高于成人（例如胫前肌和腓肠外侧肌，P  < 0.001）。

解释

在正常发育的儿童中，下肢肌肉的剪切模量随着净纵向张力角的增加而增加。建议可以比较不同测试位置和人群的值。剪切模量和年龄之间的一些关系已经确定，但需要更多的研究。