Dynamic tracking of cardiac motion fields using multi-frequency scattering parameters of an RF array – an MRI based feasibility study

Motivation: To enable high frame rate spatial mapping of cardiac mechanical motion with an array of RF antennas. Goal(s): Investigate the feasibility of estimating 2D motion fields based on measurements of wideband multi-channel RF scattering parameters. Approach: Paired CINE MRI and multi-channel wideband (55-1300 MHz) RF scattering measurements were acquired in vivo. Motion fields were determined from MRI, a Gaussian process regression model was trained and tested to predict motion fields from the RF scattering parameters. Results: 2D motion fields in a 4Ch CINE image of the heart can be reconstructed with high precision (RMS error 0.66mm) based on RF scattering measurements. Impact: We demonstrated feasibility of high precision and high framerate spatial motion mapping with RF antennas. Further validation with real-time MRI is warranted. This method could be applicable for motion tracking during medical imaging or in a low complexity care setting.