DT-MRI shows muscle structural and strength changes with ageing

My latest article, Age-related changes in human skeletal muscle microstructure and architecture assessed by diffusion-tensor magnetic resonance imaging and their association with muscle strength - published in Aging cell - was a labour of love that began back in 2015 as part of the GESTALT study of ageing. We show that diffusion-MRI-measured skeletal muscle microstructure (fractional anisotropy and mean diffusivity) and architecture (pennation angle, fascicle length, curvature, and PCSA) are associated with age and with muscle strength. This will prove important for understanding the early stages of sarcopenia - the loss of muscle mass and strength with ageing.

A bried summary of the paper is given below:

We used diffusion-tensor MRI (DT-MRI) to probe muscle microstructure and architecture in a large healthy-ageing cohort, with the aim of characterizing age-related differences and comparing to muscle strength. We recruited 94 participants (age range = 22–89 years) and measured microstructure parameters—fractional anisotropy (FA) and mean diffusivity (MD)—in 12 thigh muscles, and architecture parameters—pennation angle, fascicle length, fiber curvature, and physiological cross-sectional area (PCSA)—in the rectus femoris (RF) and biceps femoris longus (BFL). Knee extension and flexion torques were also measured for comparison to architecture measures. FA and MD were associated with age, as were pennation angle, fiber curvature, fascicle length, and PCSA in the RF, while in the BFL only curvature and fascicle length were associated with age. In the RF, pennation angle and PCSA were associated with strength; in the BFL, only PCSA was associated with strength. Our results show skeletal muscle architectural changes with ageing and intermuscular differences in microstructure. DT-MRI may prove useful for elucidating muscle changes in the early stages of sarcopenia and monitoring interventions aimed at preventing age-associated changes in muscle that lead to functional impairment.