Ultrafast imaging of the heart using circular wave synthetic imaging with phased arrays

The concept of synthetic imaging using circular wave is proposed to image with a very large field of view and at a very high frame rate (>1000 images/sec) heart motions with a conventional cardiac phased array probe. The goal of this study is to demonstrate in vivo the feasibility of this technique. Experiments are first performed in-vitro on ultrasound phantoms to optimize the trade-off between image quality and frame rate. An in vivo study is then performed on 10 sheep with a conventional phased array probe placed directly on the epicardium at different locations to obtain cine-loop of a complete heart cycle in the conventional imaging planes (long and short axis). After classical post processing of acquired cine-loop (wall tracking and tissue Doppler velocity estimation), the propagation of mechanical waves induced naturally during the heart cycle such as aortic and mitral valves closure can be observed.