Ultrasound imaging can be improved with higher order arrays through elevation dynamic focusing in future, higher channel count systems. However, modifications to current system hardware could yield increased imaging depth-of-field with 1.75D arrays (arrays with individually addressable elements, several rows in elevation) through the use of synthetic elevation imaging. We describe synthetic elevation beamforming methods and its implementation with our 8 x 128, 1.75D array (Tetrad Co., Englewood, CO). This array has been successfully interfaced with a Siemens Elegra scanner for summed RF and single channel RIP data acquisition. Individual rows of the 8 x 128 array can be controlled, allowing for different aperture configurations on transmit and receive beamforming. Advantages of using this array include finer elevation sampling, a larger array footprint for aberration measurements, and elevation focusing. We discuss system tradeoffs that occur in implementing synthetic receive and synthetic transmit /receive elevation focusing and show significant image quality improvements in simulation and phantom data results.
Ieee Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2003, Vol 50, Issue 1, p. 40-57