title: In vivo quantification of the shear modulus of the human Achilles tendon during passive loading using shear wave dispersion analysis.
abstract: The shear wave velocity dispersion was analyzed in the Achilles tendon (AT) during passive dorsiflexion using a phase velocity method in order to obtain the tendon shear modulus (C 55). Based on this analysis, the aims of the present study were (i) to assess the reproducibility of the shear modulus for different ankle angles, (ii) to assess the effect of the probe locations, and (iii) to compare results with elasticity values obtained with the supersonic shear imaging (SSI) technique. The AT shear modulus (C 55) consistently increased with the ankle dorsiflexion (N = 10, p < 0.05). Furthermore, the technique showed a very good reproducibility (all standard error of the mean values <10.7 kPa and all coefficient of variation (CV) values ⩽ 0.05%). In addition, independently from the ankle dorsiflexion, the shear modulus was significantly higher in the proximal location compared to the more distal one. The shear modulus provided by SSI was always lower than C55 and the difference increased with the ankle dorsiflexion. However, shear modulus values provided by both methods were highly correlated (R = 0.84), indicating that the conventional shear wave elastography technique (SSI technique) can be used to compare tendon mechanical properties across populations. Future studies should determine the clinical relevance of the shear wave dispersion analysis, for instance in the case of tendinopathy or tendon tear.
authors.affiliation: Institut Langevin-Ondes et Images, ESPCI Paris, PSL Research University, CNRS UMR7587, INSERM U979, 1 rue Jussieu, 75238 Paris cedex 05, France.
authors.forename: C
authors.initials: C
authors.lastname: Helfenstein-Didier
authors.forename: R J
authors.initials: RJ
authors.lastname: Andrade
authors.forename: J
authors.initials: J
authors.lastname: Brum
authors.forename: F
authors.initials: F
authors.lastname: Hug
authors.forename: M
authors.initials: M
authors.lastname: Tanter
authors.forename: A
authors.initials: A
authors.lastname: Nordez
authors.forename: J-L
authors.initials: JL
authors.lastname: Gennisson
mesh_terms: D000125:Achilles Tendon / Q000502:physiology*; D000328:Adult; D000465:Algorithms; D001696:Biomechanical Phenomena; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods* / Q000592:standards; D006801:Humans; D008297:Male; D015203:Reproducibility of Results