Characterizing Metabolic and Compositional Heterogeneity of Calf Muscle Using CEST MRI at 3 T

Different human calf muscles have specialized functions, leading to inherent metabolic differences. Imaging the metabolic and compositional properties of calf muscles is important for evaluating muscle health. This study aims to characterize the metabolic and compositional heterogeneity of calf muscle by chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) at 3 T. CEST MRI was performed on 14 healthy volunteers. CEST contrasts (amide, PCr, rNOE, and MT) were extracted from segmented muscles, and used for correlation analysis with age, fat content, BMI, and muscular strength. Distinct CEST signatures were observed between deep stabilizer and superficial powerhouse muscles. Significant correlations (e.g., rNOE vs. strength) revealed the impact of adiposity on muscle physiology. This study demonstrates the feasibility of CEST MRI for noninvasively characterizing muscle-specific metabolic and compositional alterations, revealing distinct signatures between functionally distinct muscle groups and significant associations with adiposity and body composition.