Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10433262 | Journal of Biomechanics | 2011 | 8 Pages |
Abstract
Dynamic elastography (DE) is a new tool to study mechanical behavior of soft tissues via their motion response to propagating shear waves. This technique characterized viscoelasticity of 9 porcine whole blood samples (3 animals) during coagulation for a shearing frequency of 70Â Hz, and after complete clot formation between 50 and 160Â Hz. Clot storage (Gâ²) and loss (Gâ³) moduli were calculated from shear wave velocity and attenuation. Temporal evolutions of Gâ² and Gâ³ during coagulation were typified with 4 parameters: maximum change in elasticity (Gâ² slopemax), elasticity after 120Â min of coagulation (Gâ²max), time occurrence of Gâ³ maximum (te) and Gâ³ at the plateau (Gâ³plateau). Gâ² and Gâ³ frequency dependence of completely formed blood clots was fitted with 5 standard rheological models: Maxwell, Kelvin-Voigt, Jeffrey, Zener and third-order generalized Maxwell. DE had sufficient sensitivity to follow the coagulation kinetics described by a progressive increase in Gâ², while Gâ³ transitory increased followed by a rapid stabilization. Inter- and intra-animal dispersions (InterAD and IntraAD) of Gâ²max (InterAD=15.9%, IntraAD=9.1%) showed better reproducibility than Gâ² slopemax (InterAD=40.4%, IntraAD=21.9%), te (InterAD=27.4%, IntraAD=18.7%) and Gâ³plateau (InterAD=58.6%, IntraAD=40.2%). Gâ² evolution within the considered range of frequency exhibited an increase, followed by stabilization to a plateau, whereas Gâ³ presented little variations with convergence at a quasi-constant value at highest frequencies. Residues Ïâ, describing the goodness of fit between models and experimental data, showed statistically (p<0.05) that the Kelvin-Voigt model was less in agreement with experimental data than other models. The Zener model is recommended to predict Gâ² and Gâ³ dispersion of coagulated blood over the explored frequency range.
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Biomedical Engineering
Authors
Cédric Schmitt, Anis Hadj Henni, Guy Cloutier,