Age-related changes in human skeletal muscle microstructure and architecture assessed by DT-MRI and their association with muscle strength

Here we apply diffusion-tensor-(DT)-MRI to study muscle microstructural and architectural changes with healthy ageing in 94 participants (median age=56, range=22-89yrs). Fractional anisotropy (FA) and mean diffusivity (MD), were calculated for 12 thigh muscles, as were pennation angle, fascicle length, fibre curvature, and physiological cross-sectional area (PCSA) for the rectus femoris and biceps femoris longus. Knee extension/flexion torques were also measured. FA and MD were significantly associated with age (β=0.34 and −0.34, p<0.05), as were architecture parameters. Pennation angle and PCSA were positively associated with strength. This may prove useful for studying muscle response to interventions designed to delay sarcopenia.