Imaging biomarkers of skeletal muscle strength across the lifespan

Motivation: Physical therapy and exercise are proposed to slow down the aging-associated loss in muscle strength, but it is currently not known which compositional or architectural aspects of skeletal muscle cause reduced muscle strength. Goal(s): Our goal was to exploit quantitative MRI to identify determinants of muscle strength production across the lifespan. Approach: We used quantitative MRI (fat fraction, diffusion parameters, fiber length and muscle T2) to predict quadriceps torque (n=24, 30-80 y/o). Results: We found that the inclusion of FA greatly improved the prediction of torque over morphology alone. This might be explained with modifications of fiber typing with aging. Impact: We have demonstrated that DTI parameters provide quantitative metrics of muscle quality which can be used to study force production in skeletal muscle, independently of volume. These compositional aspects might be amenable to interventions and provide specific targets for treatment.