A Transient Elastography System for Soft-Tissue Stiffness Measurement and Wavelet De-Noising of Displacement Estimation in Elastogram

Elastography is an emerging ultrasonic imaging technique. A system based on transient elastography is built to measure biological tissues\´ stiffness in the paper. Then, wavelet de-noising of the displacement estimatation to reduce artifacts due to high overlap in transient elastography is presented. High overlap between data segments is essential to improve axial resolution in transient elastography. However, overlap more than 90% or more causes the increase of correlated errors, which in turn generate "worm" artifact in strain. Wavelet de-noising can reduce errors in the displacement estimates strikingly by thresholding the wavelet coefficients, therefore reducing the worm artifact. The strain results from tissue-mimicking phantoms, illustrates the improvement in the elastogram by wavelet de-noising algorithm.