On the use of envelope and RF signal decorrelation as tissue strain estimators.

Bamber and Bush (1995) used the correlation coefficient for freehand elasticity imaging. Varghese and Ophir (1996) found it to be a biased estimator of strain with a large variability. In this study, we systematically investigate the effect of changes in various system and processing parameters on the performance of the correlation coefficient strain estimator, and demonstrate, using simulated data, that noise and frequency-dependent attenuation can introduce variable bias in this estimator.