Roumei Wang,1,* Shien Fu,2,* Rui Huang,3,* Chengcheng Qiu,1 Yunxia Tang,1 Yaoli Liu1 

1Department of Medical Ultrasound, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People’s Republic of China; 2Department of Endocrinology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People’s Republic of China; 3College of Public Hygiene of Guangxi Medical University, Guangxi Medical University, Nanning, Guangxi, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Yaoli Liu, Department of Medical Ultrasound, The First Affiliated Hospital of Guangxi Medical University, 6 Shuangyong Road, Nanning, Guangxi, 530021, People’s Republic of China, Tel +86-771-5356706, Email 100youngly@163.com

Objective: This study aimed to evaluate the quadriceps femoris in patients with chronic thyrotoxic myopathy (CTM) using musculoskeletal ultrasound and to explore its practical clinical value for the diagnosis of CTM.
Methods: A total of 241 subjects recruited from the First Affiliated Hospital of Guangxi Medical University were surveyed for detailed medical history and underwent grip strength tests, fixed-distance walking, and quadriceps femoris ultrasound examinations. Differences in muscle parameters between the CTM, non-CTM, and healthy groups were analyzed. An Receiver operating characteristic (ROC) curve was established to analyze the predictive value of various ultrasound measurements for CTM, and Spearman correlation analysis and binary logistic regression were applied to explore the factors associated CTM.
Results: The quadriceps femoris contraction index, muscle thickness, muscle cross-sectional area, and pennation angle in the CTM group were significantly lower than those in the non-CTM and healthy groups (p< 0.01). The ROC curve prediction showed that the pennation angle had the best sensitivity and specificity for diagnosing myogenesis, with an area under the curve of 89%. Moreover, the pennation angle of the CTM group was positively correlated with step speed (r=0.245, p=0.031) and body surface area (r=0.276, p=0.014), but negatively correlated with age (r=− 0.306, p=0.007). Regression analysis showed that the quadriceps femoris contraction index, muscle thickness, pennation angle, and cross-sectional area were factors that related the CTM. After adjusting for potential confounding factors, the association between Muscle Bundle Length and CTM became significant (OR=1.99, 95% CI: 1.22, 3.35, p=0.007). Muscular echo in patients was observed to varying degrees of enhancement.
Conclusion: Musculoskeletal ultrasonography in the quantitative analysis of muscle parameters and muscle echo of the quadriceps femoris can provide essential imaging evidence for predicting CTM.

Keywords: chronic thyrotoxic myopathy, musculoskeletal ultrasound, muscle echo intensity, Heckmatt Scale