title: Three-dimensional finite element modeling of guided ultrasound wave propagation in intact and healing long bones.
abstract: The use of guided waves has recently drawn significant interest in the ultrasonic characterization of bone aiming at supplementing the information provided by traditional velocity measurements. This work presents a three-dimensional finite element study of guided wave propagation in intact and healing bones. A model of the fracture callus was constructed and the healing course was simulated as a three-stage process. The dispersion of guided modes generated by a broadband 1-MHz excitation was represented in the time-frequency domain. Wave propagation in the intact bone model was first investigated and comparisons were then made with a simplified geometry using analytical dispersion curves of the tube modes. Then, the effect of callus consolidation on the propagation characteristics was examined. It was shown that the dispersion of guided waves was significantly influenced by the irregularity and anisotropy of the bone. Also, guided waves were sensitive to material and geometrical changes that take place during healing. Conversely, when the first-arriving signal at the receiver corresponded to a nondispersive lateral wave, its propagation velocity was almost unaffected by the elastic symmetry and geometry of the bone and also could not characterize the callus tissue throughout its thickness. In conclusion, guided waves can enhance the capabilities of ultrasonic evaluation.
authors.affiliation: Department of Medical Physics, Medical School, University of Ioannina, GR 451 10 Ioannina, Greece.
authors.forename: Vasilios C
authors.initials: VC
authors.lastname: Protopappas
authors.forename: Iraklis C
authors.initials: IC
authors.lastname: Kourtis
authors.forename: Lampros C
authors.initials: LC
authors.lastname: Kourtis
authors.forename: Konstantinos N
authors.initials: KN
authors.lastname: Malizos
authors.forename: Christos V
authors.initials: CV
authors.lastname: Massalas
authors.forename: Dimitrios I
authors.initials: DI
authors.lastname: Fotiadis
mesh_terms: D000818:Animals; D001847:Bone Diseases / Q000503:physiopathology*; D003198:Computer Simulation; D008954:Models, Biological; D012756:Sheep; D013977:Tibia / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology* / Q000528:radiation effects; D014057:Tomography, X-Ray Computed; D014465:Ultrasonics; D014945:Wound Healing