Methods for dynamic range expansion and enhancement of the signal-to-noise ratio in elastography

Two methods are discussed to increase the dynamic range and enhance the signal-to-noise ratio in elastography (SNR/sub e/). One method uses variable applied strains to expand the elastographic dynamic range by selecting the strain estimates with the highest SNR/sub e/ out of a multitude of strain estimates. The second one is a completely new estimator that estimates the strain by an iterative temporal stretching algorithm of the windowed postcompression RF echo signal. The authors examine these methods using 2D finite element simulations and resulting experimental strain filters. Finally, the combination of these two methods is shown to produce an elastogram with higher dynamic range as well as SNR/sub e/.