title: A hybrid displacement estimation method for ultrasonic elasticity imaging.
abstract: Axial displacement estimation is fundamental to many freehand quasistatic ultrasonic strain imaging systems. In this paper, we present a novel estimation method that combines the strengths of quality-guided tracking, multi-level correlation, and phase-zero search to achieve high levels of accuracy and robustness. The paper includes a full description of the hybrid method, in vivo examples to illustrate the method's clinical relevance, and finite element simulations to assess its accuracy. Quantitative and qualitative comparisons are made with leading single- and multi-level alternatives. In the in vivo examples, the hybrid method produces fewer obvious peak-hopping errors, and in simulation, the hybrid method is found to reduce displacement estimation errors by 5 to 50%. With typical clinical data, the hybrid method can generate more than 25 strain images per second on commercial hardware; this is comparable with the alternative approaches considered in this paper.
authors.affiliation: University of Cambridge, Department of Engineering, Cambridge, UK. chenlujie@gmail.com
authors.forename: Lujie
authors.initials: L
authors.lastname: Chen
authors.forename: R
authors.initials: R
authors.lastname: Housden
authors.forename: Graham
authors.initials: G
authors.lastname: Treece
authors.forename: Andrew
authors.initials: A
authors.lastname: Gee
authors.forename: Richard
authors.initials: R
authors.lastname: Prager
mesh_terms: D000465:Algorithms; D054459:Elasticity Imaging Techniques / Q000379:methods*; D020342:Finite Element Analysis; D012044:Regression Analysis; D012815:Signal Processing, Computer-Assisted; D014159:Transducers