Experimental investigation into radar-based central blood pressure estimation

To assess whether radar technology can be used for monitoring blood pressure via information from the aorta, two experiments were performed: (i) measurements on a phantom model and (ii) acquisitions on a human subject for in vivo experiments. A linear dependency of phase on radius in the radar echoes in the phantom model showed that the information regarding the radius of a circular, cylindrical object depended on the clutter environment: in a low-clutter case two distinct reflections were identified, whereas in the high-clutter case it was possible to extract a proxy. Radar echoes from antennas strapped to the back of a human subject showed a clear signature from a discernible, distinct reflector believed to be the aorta. However, as for the high-clutter case, only a proxy for aortic radius is available as basis for estimation, which is most likely coupled with aortic displacements.