Time-Resolved MRI Kinesiology: Reconstructing force and velocity during active loading

Force and velocity are two important quantities for studying muscles, but retrieving these quantities using MRI is challenging. Spectro-Dynamic MRI allows the characterization of dynamical systems at a high spatial and temporal resolution directly from k-space data. Using an iterative reconstruction algorithm, we can reconstruct time-resolved MR images, time-resolved motion fields, mechanical parameters, and an activation force, at a temporal resolution of 11 ms. As a proof-of-principle, MR data was acquired with a motion phantom moving like an actively driven linear elastic system. All dynamic variables could be reconstructed accurately. This method could become useful for studying muscles under dynamic loads.