A method for intrapulse spatial compounding

The speckle texture in ultrasound images is inherent to the coherent beamforming process for diffuse targets and limits the detectability of low contrast targets. Speckle compounding takes advantage of the limited spatial and frequency correlation of speckle by incoherently averaging multiple realizations to reduce the variance and smooth the background texture. Conventionally, spatial compounding requires multiple transducer positions, multiple transmit firings or splitting the active receive aperture. We propose a method to separate multiple decorrelated components from within a focused transmit beam in order to overcome these limitations. Synthetic aperture focusing methods are used in conjunction with a traditional phased array scan to produce multiple subimages to be used in spatial compounding. An average 21.7 ± 5.6% improvement in contrast-to-noise ratio was observed for small (5-10 mm) hypoechoic targets in simulation and in vivo liver using the proposed technique.