Ultrasound Tissue Characteristics of Diabetic Muscles and Tendons: Associations with Strength and Laboratory Blood Tests

Background. This study sought to compare the ultrasound tissue characteristics of the muscles (including muscle thickness, echo intensity, and stiffness) and tendons (including thickness, stiffness, and peak spatial frequency radius (PSFR)) of participants with or without diabetes mellitus. Moreover, the study sought to determine any relationships between the muscle stiffness and strength or tendon PSFR and the results of blood tests, including the glycation or lipid profiles, of the diabetics. Methods. Twenty-three participants with type 2 diabetes mellitus and nineteen controls without a history of diabetes were recruited. Results. The diabetic muscles exhibited less thickness (P=0.024), greater echo intensity (P=0.033 and 0.002), and lower muscle stiffness (P=0.015 and 0.009) than the control muscles. Furthermore, the diabetic tendons exhibited a lower PSFR (P ranged between 0.037 and <0.001). There were correlations between the resting stiffness of the gastrocnemius muscle and the height of heel lifting (r=0.450, P=0.031), between the PSFR in the patellar tendon and the hemoglobin A1c level (r= -0.539, P=0.017), and between the PSFR in the Achilles tendon and the high-density lipoprotein cholesterol level (r=0.545, P=0.019). Conclusions. The diabetic muscles and tendons exhibited morphomechanical changes associated with force capacity or markers of insulin resistance. Clinical applications of musculoskeletal ultrasound techniques to diabetics include using them to design exercise strategies and for microstructural screening.