title: Intervertebral disc characterization by shear wave elastography: An in vitro preliminary study.
abstract: Patient-specific numerical simulation of the spine is a useful tool both in clinic and research. While geometrical personalization of the spine is no more an issue, thanks to recent technological advances, non-invasive personalization of soft tissue's mechanical properties remains a challenge. Ultrasound elastography is a relatively recent measurement technique allowing the evaluation of soft tissue's elastic modulus through the measurement of shear wave speed. The aim of this study was to determine the feasibility of elastographic measurements in intervertebral disc. An in vitro approach was chosen to test the hypothesis that shear wave speed can be used to evaluate intervertebral disc mechanical properties and to assess measurement repeatability. In total, 11 oxtail intervertebral discs were tested in compression to determine their stiffness and apparent elastic modulus at rest and at 400 N. Elastographic measurements were performed in these two conditions and compared to these mechanical parameters. The protocol was repeated six times to determine elastographic measurement repeatability. Average shear wave speed over all samples was 5.3 ± 1.0 m/s, with a repeatability of 7% at rest and 4.6% at 400 N; stiffness and apparent elastic modulus were 266.3 ± 70.5 N/mm and 5.4 ± 1.1 MPa at rest, respectively, while at 400 N they were 781.0 ± 153.8 N/mm and 13.2 ± 2.4 MPa, respectively. Correlations were found between elastographic measurements and intervertebral disc mechanical properties; these preliminary results are promising for further in vivo application.
authors.affiliation: Arts et Métiers ParisTech, LBM, Paris, France c.vergari@gmail.com.
authors.forename: Claudio
authors.initials: C
authors.lastname: Vergari
authors.affiliation: Arts et Métiers ParisTech, LBM, Paris, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Rouch
authors.affiliation: Arts et Métiers ParisTech, LBM, Paris, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Dubois
authors.affiliation: Arts et Métiers ParisTech, LBM, Paris, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Bonneau
authors.affiliation: Arts et Métiers ParisTech, LBM, Paris, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Dubousset
authors.affiliation: Institut Langevin, Ondes et Images, ESPCI ParisTech, CNRS UMR7587, INSERM U979, Paris, France.
authors.forename: Mickael
authors.initials: M
authors.lastname: Tanter
authors.affiliation: Institut Langevin, Ondes et Images, ESPCI ParisTech, CNRS UMR7587, INSERM U979, Paris, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Gennisson
authors.affiliation: Arts et Métiers ParisTech, LBM, Paris, France.
authors.forename: Wafa
authors.initials: W
authors.lastname: Skalli
keywords: Spine; elastic modulus; intervertebral disc; quantitative ultrasound; soft tissue; stiffness