A simulation frame work to optimize volumetric cardiac imaging on a multiplexed system

Cardiac volumetric ultrasound imaging using 2D matrix array transducers makes use of probes containing thousands of elements. For maximal beam forming flexibility, fully wired systems are preferable but cabling remains an issue in terms of practicality, as does the number of electronic channels in terms of cost. Multiplexed (MUXed) systems could offer an attractive solution as they limit the number of electronic channels as well as the cable dimensions while keeping all transducer elements individually accessible. However, as not all transducer elements can be controlled or read out independently, optimizing beam forming on a multiplexed system is not trivial. In this paper, a framework to find an optimal MUXed configuration for a 3D ultrasound system is presented. The framework has been applied to optimize a 32×32 element phased array transducer combined with a 256-channel front-end using a 1:4 MUX for cardiac imaging. In this initial study, we concentrated on transmit multiplexing as repeated acquisitions could provide the complete channel data set. As such, effects of receive MUX could be avoided assuming motion is limited. The transmit MUXed optimized solution showed a pressure field with a narrow main lobe and 6dB lower side lobes compared to a bench mark beam profile obtained from a fully wired configuration (i.e. without transmit MUX).