A visualization of nonlinear elasticity property of tissues by ultrasound

Author(s):  
Naotaka Nitta ◽  
Tsuyoshi Shiina
2019 ◽  
Vol 54 (8) ◽  
pp. 1182-1188
Author(s):  
A. A. Markin ◽  
M. Yu. Sokolova
Keyword(s):  

Author(s):  
Guillaume Renaud ◽  
Samuel Callé ◽  
Jean-Pierre Remenieras ◽  
Marielle Defontaine

2020 ◽  
Author(s):  
Lucian Popescu ◽  
Nelu-Mihai Trofenciuc ◽  
Simina Crisan ◽  
Aurora Diana Bordejevic ◽  
Alexandru Mischie ◽  
...  

BACKGROUND A systematic and quantitative comparative analysis for this subject has not been done so far. Thus defined, the coefficient of elasticity is a whole new dimension. OBJECTIVE This study proposes a new mathematical myocardium elasticity property modeling in characterizing of the ventricular diastole and systole. METHODS The study group consisted of 2283 consecutive patients evaluated by echocardiography. The mathematical approach is made starting from energetic consideration, by applying the energy conservation low for the blood entering from left atrium into left ventricle during diastole period. RESULTS Analyzing all the data obtained we developed two brand new coefficients to describe the cardiac cycle and we had verified if the coefficients are correlated with classically used parameters. We consider that the energetic approach take into consideration the whole mechanical movement that is happening inside the heart and can offer a very synthetic and scientific solid view about the cardiac cycle. CONCLUSIONS The new coefficients are simply to be calculated and as you will see from our research the correlation with other classically used parameters is obvious. The direct physical approach of blood flow within the heart can generate new, beneficial perspectives in diagnosing various heart conditions, or even in understanding how works the filling of the ventricles and atria during a heartbeat.


2021 ◽  
Vol 11 (11) ◽  
pp. 4748
Author(s):  
Monika Balázsová ◽  
Miloslav Feistauer ◽  
Jaromír Horáček ◽  
Adam Kosík

This study deals with the development of an accurate, efficient and robust method for the numerical solution of the interaction of compressible flow and nonlinear dynamic elasticity. This problem requires the reliable solution of flow in time-dependent domains and the solution of deformations of elastic bodies formed by several materials with complicated geometry depending on time. In this paper, the fluid–structure interaction (FSI) problem is solved numerically by the space-time discontinuous Galerkin method (STDGM). In the case of compressible flow, we use the compressible Navier–Stokes equations formulated by the arbitrary Lagrangian–Eulerian (ALE) method. The elasticity problem uses the non-stationary formulation of the dynamic system using the St. Venant–Kirchhoff and neo-Hookean models. The STDGM for the nonlinear elasticity is tested on the Hron–Turek benchmark. The main novelty of the study is the numerical simulation of the nonlinear vocal fold vibrations excited by the compressible airflow coming from the trachea to the simplified model of the vocal tract. The computations show that the nonlinear elasticity model of the vocal folds is needed in order to obtain substantially higher accuracy of the computed vocal folds deformation than for the linear elasticity model. Moreover, the numerical simulations showed that the differences between the two considered nonlinear material models are very small.


Author(s):  
J. Sivaloganathan

In this paper we study the stability of a class of singular radial solutions to the equilibrium equations of nonlinear elasticity, in which a hole forms at the centre of a ball of isotropic material held in a state of tension under prescribed boundary displacements. The existence of such cavitating solutions has been shown by Ball[1], Stuart [11] and Sivaloganathan[10]. Our methods involve elements of the field theory of the calculus of variations and provide a new unified interpretation of the phenomenon of cavitation.


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