MRI-based Assessment of Disease-Specific Risk Profiles for Sarcopenia in Chronic Liver Disease

Objective To determine whether sarcopenia-related imaging markers differ by disease etiology in chronic liver disease (CLD), using magnetic resonance elastography (MRE) and proton density fat fraction (PDFF). Methods We retrospectively analyzed 131 CLD patients (77 with metabolic dysfunction-associated steatohepatitis [MASH], 54 with viral hepatitis) who underwent MRI, including PDFF and MRE. Sarcopenia was defined by L2 skeletal muscle index thresholds (< 42 cm²/m² for men, < 38 cm²/m² for women). Multivariable logistic regression with interaction terms assessed associations of age, BMI, PDFF, liver stiffness, and aminotransferases with sarcopenia. Results Sarcopenia was observed in 56% of patients. In the overall cohort, older age (OR = 1.05, p = 0.01), lower PDFF (OR = 0.93, p = 0.03), and reduced stiffness (OR = 0.51, p = 0.006) were independently associated with sarcopenia. Interaction analysis showed significant effect modification for BMI (p = 0.02) by etiology. Subgroup models revealed that in MASH, sarcopenia was associated with older age, lower PDFF, and reduced stiffness, whereas in viral hepatitis, sarcopenia correlated with higher stiffness and lower BMI. Conclusion Sarcopenia in CLD shows distinct etiologic profiles: metabolic depletion in MASH and fibrosis-driven nutritional deficiency in viral hepatitis. MRI-derived liver fat and stiffness provide etiology-specific insights into sarcopenia pathogenesis, supporting tailored management strategies.