Speckle tracking methods for ultrasonic elasticity imaging using short-time correlation

In ultrasound elasticity imaging, strain decorrelation is a major source of error in displacements estimated using correlation techniques. This error can be significantly decreased by reducing the correlation kernel. Addition al gains in signal-to-noise ratio (SNR) are possible by filtering the corre lation functions prior to displacement estimation. Tradeoffs between spatia l resolution and estimate variance are discussed, and estimation in elastic ity imaging is compared to traditional time-delay estimation. Simulations a nd experiments on gel-based phantoms are presented. The results demonstrate that high resolution, high SNR strain estimates can be computed using smal l correlation kernels (on the order of the autocorrelation width of the ult rasound signal) and correlation filtering.