Real-time volumetric ultrasound using near-simultaneous beams

Real-time 3D ultrasound (RT3D) requires high data acquisition rates (DAR) to achieve fast frame rates, wide fields of view and high resolution. Current state-of-the-art RT3D scanners employ parallel receive processing to increase the DAR by acquiring multiple receive lines from a single broad transmit beam. However, the DAR achieved in these RT3D scanners is insufficient to acquire volumes at real time rates with a resolution and field of view comparable to commercial 2D scanners. The level of useful receive parallelism is constrained by the area insonified by each transmit beam. A broader transmit beam usually requires a smaller transducer aperture, which reduces the transmitted energy and may produce more image clutter.; It is hypothesized that the use of multiple near-simultaneous transmit beams coupled with parallel receive processing will increase the DAR by a factor equal to the number of simultaneous transmits without decreasing image quality. A novel phased-array transducer layout that enables multiple near-simultaneous transmit beams while restricting interference among beams to -60 dB has been developed. Simulations are substantiated by water tank experiments that demonstrate the efficacy of the design. Phantom and in vivo images generated with single and multiple near-simultaneous transmits are compared. Finally, an algorithm for real-time volume rendering of the acquired 3D datasets is described, and images from its implementation are presented.