• Aucun résultat trouvé

AN ULTRASOUND PROBE INDENTER FOR THE NON-LINEAR MECHANICAL CHARACTERIZATION OF SOFT TISSUES

N/A
N/A
Protected

Academic year: 2021

Partager "AN ULTRASOUND PROBE INDENTER FOR THE NON-LINEAR MECHANICAL CHARACTERIZATION OF SOFT TISSUES"

Copied!
2
0
0

Texte intégral

(1)

HAL Id: hal-03040331

https://hal.archives-ouvertes.fr/hal-03040331

Submitted on 7 Dec 2020

HAL is a multi-disciplinary open access

archive for the deposit and dissemination of

sci-entific research documents, whether they are

pub-lished or not. The documents may come from

teaching and research institutions in France or

abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est

destinée au dépôt et à la diffusion de documents

scientifiques de niveau recherche, publiés ou non,

émanant des établissements d’enseignement et de

recherche français ou étrangers, des laboratoires

publics ou privés.

AN ULTRASOUND PROBE INDENTER FOR THE

NON-LINEAR MECHANICAL

CHARACTERIZATION OF SOFT TISSUES

Ajeethan Arulrajah, Benoît Wach, Laurent Barbé, Daniel George, Jonathan

Vappou, Simon Chatelin

To cite this version:

Ajeethan Arulrajah, Benoît Wach, Laurent Barbé, Daniel George, Jonathan Vappou, et al.. AN

UL-TRASOUND PROBE INDENTER FOR THE NON-LINEAR MECHANICAL

CHARACTERIZA-TION OF SOFT TISSUES. International Tissue Elasticity Conference (ITEC), Sep 2018, Avignon,

France. �hal-03040331�

(2)

2018 Abstract Submission Forms and Instructions 1 27 March 2018

Figure 1: Indentation Prototype

(a) fully assembled view (b) exploded view

### AN ULTRASOUND PROBE INDENTER FOR THE NON-LINEAR MECHANICAL

CHARACTERIZATION OF SOFT TISSUES.

Ajeethan Arulrajah1,2, Benoît Wach2, Laurent Barbé1, Daniel George1, Jonathan Vappou1 and Simon

Chatelin1.

1ICube, University of Strasbourg, CNRS UMR7357, 1 place de l’hôpital, Strasbourg, FRANCE; 2IHU Strasbourg, Institute of Image-Guided Surgery, 1 place de l’hôpital, Strasbourg, FRANCE.

Background: Ultrasound elastography techniques allow measuring quantitatively the viscoelastic

properties of soft tissue. Nevertheless, most of them are restricted to small deformation [1], while soft tissues exhibit strong non-linear elastic behavior under large deformation. Little work is currently available in the literature on the in vivo quantification of non-linear parameters of soft tissues [2]–[5].

Aims: The aim of this study is to develop a method for estimating non-linear elastic parameters of soft

tissues. The method relies on the coupling between ultrasound displacement imaging and indentation. By the use of numerical model identification, the non-linear elastic parameters are non-invasively extracted.

Methods: The approach can be described in three main steps (fig 1).

i. Indentation process: a 9 MHz ultrasound linear probe (L12-5 50mm, Philips healthcare, NL) is used as indenter to generate large deformations (~20% of strain with maximal strain rate of 0.1 s-1) in the

tissue. The probe is attached to a robotized prototype and a force sensor is used to measure the force (6 axis Force/Torque sensor Nano17, ATI Industrial Automation, NC, USA) applied by the indenter to the tissue.

ii. Imaging part: the same ultrasound probe is used to acquire beamformed radiofrequency (RF) signals during the indentation at a frame rate of 500 Hz, using a plane wave beamforming sequence with an acquisition system (Verasonics Inc., WA, USA). 2D displacement fields are computed offline using a normalized cross correlation algorithm [6].

iii. Identification process: the indentation experiment is simulated numerically using a commercial finite element software (Abaqus Simulia, Dassault Systèmes, FR). Tissue behavior is modeled using a hyper-elastic model (Neo-Hookean) and 2D displacement maps are computed subsequently. The identification of Neo-Hookean parameters is performed through minimization of the error between the experimental and the numerical displacement fields using the simplex algorithm [7].

To validate this method, an experiment on a polyvinyl alcohol hyper-elastic cryogel was conducted. Hyper-elastic properties were compared to those obtained with rheometry tests (uniaxial compression) as the ground truth.

Results: By application on a controlled gel phantom and comparison with classical rheometry

measurements, we showed that the proposed method provides a good estimation of the non-linear behavior (hyper-elastic) parameters of the soft materials.

Conclusions: The proposed method enables the characterization of the non-linear mechanical properties

of soft tissues for large deformations, such as liver tissue, non-invasively. The quantitative rheological models of liver elasticity could then be used to improve the numerical liver models used in surgical simulators. While here applied for Neo-Hookean hyper-elasticity, this technique thought to be applied for the characterization of a large variety of soft tissues by specific complexifications of the identified model.

Acknowledgements: This work was supported by the IHU Strasbourg (Institut Hospitalo-Universitaire, Institute of

Image Guided Surgery, ANR-10-IAHU-02) and under the Investissements d’Avenir program for the Labex CAMI

(Computed Assisted Medical Interventions, ANR-11-LABX-004).

References: [1] J Vappou 2012, Crit. Rev. Biomed. Eng. 40(2), 121-34 [2] Oberai et al. 2009, PMB 54(5), 1191-207 [3]

Hall et al. 2009, Proc. EMBS IEEE Conf. 1967–70 [4] Renier et al. 2007, Proc. IUS IEEE 554–7 [5] Bernal et al. 2016,

Références

Documents relatifs

Though numerous studies have dealt with the α− methods, there is still a paucity of publi- cations devoted to the clarification of specific issues in the non-linear regime, such

However, the study of the non-linear Boltzmann equation for soft potentials without cut-off [ 20 ], and in particular the spectral analysis its linearised version (see for instance [

First, we map the fundamental matrix given by the 8 point algorithm to the closest essential matrix [8], and use this as an initial solution for the non-linear optimization. Hence,

Weakly nonlinear viscoelastic Landau’s theory, widely used in acoustical physic, is introduced into a Finite Element formulation to model the nonlinear behaviour of finite

In this paper, sufficient conditions for the robust stabilization of linear and non-linear fractional- order systems with non-linear uncertainty parameters with fractional

Ultrasounds (5 MHz) allow to detect the displacements induced by the shear waves (200 Hz) inside soft biological tissues.. These shear waves reveals pieces of information about

In imperfect competition markets, the consumer share (respectively producer share) of consumption taxes increases (respec- tively decreases) with respect to the elasticity of the

After considering the equilibrium problem of the bar and determining the stable and metastable solutions, we let (h, k) tending to zero and we obtain the corresponding