The Quantitative Skeletal Muscle Ultrasonography in Elderly with Dynapenia but not Sarcopenia Using Texture Analysis

(1) Background: Dynapenia is defined as lower muscle strength alone. Only a few studies have investigated muscle quality in subjects with dynapenia. (2) Methods: The muscle quality, characterized by texture parameters of biceps brachii, triceps brachii, rectus femoris, and medial gastrocnemius muscles, were collected using ultrasonography. The risk of dynapenia was assessed by the multiple logistic regression model. (3) Results: There were a total of 36 participants (72.7 ± 5.8 yrs, 1:1 case-control matched). The values of texture parameters of autocorrelation (AUT) and sum variance (SVAR) in all four muscles were higher in the dynapenia group significantly (p < 0.05). AUT and SVAR had the significant associations for dynapenia in biceps (dds ratio[OR]:2.51, 95% CI = 1.25-5.07 for AUT; OR = 1.45, 95% CI:1.1-1.91 for SVAR), triceps (OR: 2.48, 95% CI = 1.60-5.3 for AUT; OR: 1.57, 95% CI = 1.08-2.28 for SVAR), and rectus femoris (OR: 1.58, 95% CI = 1.01-2.46 for AUT; OR: 1.2, 95% CI = 1.0-1.44 for SVAR). The areas under the receiver-operating curves of all texture parameters was between 0.84-0.94 after adjusting confounding factors. (4) Conclusions: The muscle quality in the dynapenia can be detected by the texture-feature quantitative ultrasound. Ultrasound measurement in the aging muscle might be promising, and further studies should validate its application in the context of dynapenia.