Limits...
A New MRI-Based Model of Heart Function with Coupled Hemodynamics and Application to Normal and Diseased Canine Left Ventricles.

Choi YJ, Constantino J, Vedula V, Trayanova N, Mittal R - Front Bioeng Biotechnol (2015)

Bottom Line: The time-dependent endocardial surfaces are registered using a diffeomorphic mapping algorithm, while the intraventricular blood flow patterns are simulated using a sharp-interface immersed boundary method-based flow solver.The utility of the combined heart-function model is demonstrated by comparing the hemodynamic characteristics of a normal canine heart beating in sinus rhythm against that of the dyssynchronously beating failing heart.We also discuss the potential of coupled CE and hemodynamics models for various clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Johns Hopkins University , Baltimore, MD , USA ; Institute for Computational Medicine, Johns Hopkins University , Baltimore, MD , USA.

ABSTRACT
A methodology for the simulation of heart function that combines an MRI-based model of cardiac electromechanics (CE) with a Navier-Stokes-based hemodynamics model is presented. The CE model consists of two coupled components that simulate the electrical and the mechanical functions of the heart. Accurate representations of ventricular geometry and fiber orientations are constructed from the structural magnetic resonance and the diffusion tensor MR images, respectively. The deformation of the ventricle obtained from the electromechanical model serves as input to the hemodynamics model in this one-way coupled approach via imposed kinematic wall velocity boundary conditions and at the same time, governs the blood flow into and out of the ventricular volume. The time-dependent endocardial surfaces are registered using a diffeomorphic mapping algorithm, while the intraventricular blood flow patterns are simulated using a sharp-interface immersed boundary method-based flow solver. The utility of the combined heart-function model is demonstrated by comparing the hemodynamic characteristics of a normal canine heart beating in sinus rhythm against that of the dyssynchronously beating failing heart. We also discuss the potential of coupled CE and hemodynamics models for various clinical applications.

No MeSH data available.


LDDMM mapping of the template of normal canine LV endocardium to the target at SR. (A) The template (blue surface) and the target (red surface), the latter being the output of the image-based CE model. (B) LDDMM-transformed template (green surface) matches the target reasonably well. LDDMM, large deformation diffeomorphic metric mapping; LV, left ventricle; SR, sinus rhythm; CE, cardiac electromechanics.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4585083&req=5

Figure 5: LDDMM mapping of the template of normal canine LV endocardium to the target at SR. (A) The template (blue surface) and the target (red surface), the latter being the output of the image-based CE model. (B) LDDMM-transformed template (green surface) matches the target reasonably well. LDDMM, large deformation diffeomorphic metric mapping; LV, left ventricle; SR, sinus rhythm; CE, cardiac electromechanics.

Mentions: The ventricular surface of the template generated as described above is then deformed to match the LV endocardium at various stages in the cycle as obtained from the electromechanical simulation for each of the four cases investigated here. To accomplish this, the faces of each hexahedral elements of the mechanical mesh are first subdivided into fifty triangular elements to generate the ventricular luminal surface for the hemodynamic simulator. Then, the template LV surface is mapped to the “target” LV endocardium obtained from the electromechanical model using a diffeomorphic mapping algorithm known as Large Deformation Diffeomorphic Metric Mapping method (LDDMM) (Glaunes et al., 2004; Younes, 2010) as shown in Figure 5. This mapping procedure ensures that the surface grid is conformal (i.e., has the same number and connectivity of elements) from one time-frame to another.


A New MRI-Based Model of Heart Function with Coupled Hemodynamics and Application to Normal and Diseased Canine Left Ventricles.

Choi YJ, Constantino J, Vedula V, Trayanova N, Mittal R - Front Bioeng Biotechnol (2015)

LDDMM mapping of the template of normal canine LV endocardium to the target at SR. (A) The template (blue surface) and the target (red surface), the latter being the output of the image-based CE model. (B) LDDMM-transformed template (green surface) matches the target reasonably well. LDDMM, large deformation diffeomorphic metric mapping; LV, left ventricle; SR, sinus rhythm; CE, cardiac electromechanics.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585083&req=5

Figure 5: LDDMM mapping of the template of normal canine LV endocardium to the target at SR. (A) The template (blue surface) and the target (red surface), the latter being the output of the image-based CE model. (B) LDDMM-transformed template (green surface) matches the target reasonably well. LDDMM, large deformation diffeomorphic metric mapping; LV, left ventricle; SR, sinus rhythm; CE, cardiac electromechanics.
Mentions: The ventricular surface of the template generated as described above is then deformed to match the LV endocardium at various stages in the cycle as obtained from the electromechanical simulation for each of the four cases investigated here. To accomplish this, the faces of each hexahedral elements of the mechanical mesh are first subdivided into fifty triangular elements to generate the ventricular luminal surface for the hemodynamic simulator. Then, the template LV surface is mapped to the “target” LV endocardium obtained from the electromechanical model using a diffeomorphic mapping algorithm known as Large Deformation Diffeomorphic Metric Mapping method (LDDMM) (Glaunes et al., 2004; Younes, 2010) as shown in Figure 5. This mapping procedure ensures that the surface grid is conformal (i.e., has the same number and connectivity of elements) from one time-frame to another.

Bottom Line: The time-dependent endocardial surfaces are registered using a diffeomorphic mapping algorithm, while the intraventricular blood flow patterns are simulated using a sharp-interface immersed boundary method-based flow solver.The utility of the combined heart-function model is demonstrated by comparing the hemodynamic characteristics of a normal canine heart beating in sinus rhythm against that of the dyssynchronously beating failing heart.We also discuss the potential of coupled CE and hemodynamics models for various clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Johns Hopkins University , Baltimore, MD , USA ; Institute for Computational Medicine, Johns Hopkins University , Baltimore, MD , USA.

ABSTRACT
A methodology for the simulation of heart function that combines an MRI-based model of cardiac electromechanics (CE) with a Navier-Stokes-based hemodynamics model is presented. The CE model consists of two coupled components that simulate the electrical and the mechanical functions of the heart. Accurate representations of ventricular geometry and fiber orientations are constructed from the structural magnetic resonance and the diffusion tensor MR images, respectively. The deformation of the ventricle obtained from the electromechanical model serves as input to the hemodynamics model in this one-way coupled approach via imposed kinematic wall velocity boundary conditions and at the same time, governs the blood flow into and out of the ventricular volume. The time-dependent endocardial surfaces are registered using a diffeomorphic mapping algorithm, while the intraventricular blood flow patterns are simulated using a sharp-interface immersed boundary method-based flow solver. The utility of the combined heart-function model is demonstrated by comparing the hemodynamic characteristics of a normal canine heart beating in sinus rhythm against that of the dyssynchronously beating failing heart. We also discuss the potential of coupled CE and hemodynamics models for various clinical applications.

No MeSH data available.