Improvement in elastograms using multiresolution elastography

The authors analyze the performance of multiresolution elastography, where the strain estimate with the highest elastographic signal-to-noise ratio (SNR_e) obtained by processing the pre- and post-compression waveforms at different window lengths. All the objective elastographic parameters, namely: SNR_e, sensitivity dynamic range and the average resolution (defined as the cross-correlation window length) are improved with multiresolution elastography when compared to the traditional method of utilizing a single window length to generate the elastogram. Multiresolution elastography is based on the presence of an optimal window length for each strain value where the strain variance is minimized. Long-duration windows are preferred for small strains, while large strains require a small window length. The sensitivity, dynamic range and SNR, improve with an increase in the window length. However, with an increase in the window length the elastogram is degraded due to poor resolution. Experimental results using a phantom with a hard inclusion illustrate the improvement in the elastogram obtained using multiresolution analysis