Association Between Temporal Muscle Thickness and Skeletal Muscle Mass, Nutritional Status, and Physical Function in Patients With Post-stroke Hemiparesis: A Cross-Sectional Study

Introduction: Temporal muscle thickness (TMT), observed on brain magnetic resonance imaging (MRI), has emerged as a potential surrogate marker for sarcopenia. This study aimed to investigate the relationships between TMT, muscle mass, nutritional status, and lower limb motor function in individuals with post-stroke hemiparesis. Methods: This cross-sectional study enrolled 45 patients experiencing their first-ever stroke with hemiparesis, all of whom were discharged from a rehabilitation ward. TMT was assessed using T2-weighted MRI images. Muscle mass and quality were evaluated using the skeletal muscle index (SMI), extracellular water-to-total body water ratio (ECW/TBW), and phase angle (PhA). Nutritional status was determined by serum albumin levels, the Geriatric Nutritional Risk Index (GNRI), and Body Mass Index (BMI). Lower limb function was assessed using the Stroke Impairment Assessment Set Motor Function of the Lower Extremities (SIAS-MLE). Analyses were conducted using Spearman's correlation and intraclass correlation coefficients (ICCs). Results: TMT demonstrated high inter-rater reliability (ICC: 0.812 for the left side; 0.796 for the right). Positive correlations were observed between TMT and SMI, PhA, GNRI, and SIAS-MLE. A negative correlation was found with ECW/TBW. No significant correlations were identified with age, BMI or handgrip strength. Conclusion: TMT is a reliable and practical marker that correlates with muscle mass, muscle quality, nutritional status, and motor function in patients post-stroke. These findings underscore its potential role in sarcopenia screening.