Dynamical information can be a valuable source of information for cardiovascular or musculoskeletal studies. However, measuring dynamics at a high spatial and temporal resolution with conventional MRI techniques is extremely challenging. Spectro-dynamic MRI aims to infer dynamical systems directly from k-space data. It combines a measurement model, relating the measured data in k-space to the displacement fields, and a dynamical model, introducting prior knowledge about the dynamics. In addition to the displacements, the dynamical parameters of the underlying system are estimated.
Preliminary experiments have shown that spectro-dynamic MRI is able to characterize the dynamics of simple systems with up to four degrees of freedom on a millisecond timescale. Further research will expand the method towards non-rigid deformations in 3D, which will enable in vivo applications.
Figure 1: (a) Estimated displacements and (b) reconstructed images at different points in time for a coupled spherical pendulum experiment. The dynamics were estimated at a temporal resolution of 4.4 ms. In addition, the natural frequencies of the system as determined by the length of the pendula and the spring constant could be identified.
NWO-VIDI grant 2021-2026 (P.I.: Alessandro Sbrizzi)