Adaptive spectral strain estimators for elastography.
In conventional elastography, internal tissue deformations, induced by external compression applied to the tissue surface, are estimated by cross-correlation analysis of echo signals obtained before and after compression. Conventionally, strains are estimated by computing the gradient of estimated displacement. However, gradient-based algorithms are highly susceptible to noise and decorrelation, which could limit their utility. We previously developed strain estimators based on a frequency-domain (spectral) formulation that were shown to be more robust but less precise compared to conventional strain estimators, In this paper, we introduce a novel spectral strain estimator that estimates local strain by maximizing the correlation between the spectra of pre- and postcompression echo signals using iterative frequency-scaling of the latter; we also discuss a variation of this algorithm that may be computationally more efficient but less precise. The adaptive spectral strain estimator combines the advantages of time- and frequency-domain methods and has outperformed conventional estimators in experiments and 2-D finite-element simulations.
Alam
S Kaisar
SK
Riverside Research Institute, New York, NY 10038, USA. kalam@rrinyc.org
Lizzi
Frederic L
FL
Varghese
Tomy
T
Feleppa
Ernest J
EJ
Ramachandran
Sarayu
S
D000465:Algorithms; D004548:Elasticity; D020342:Finite Element Analysis; D019047:Phantoms, Imaging; D013314:Stress, Mechanical; D014159:Transducers; D014465:Ultrasonics