TY - JOUR
T1 - Improved identifiability of myocardial material parameters by an energy-based cost function
AU - Nasopoulou, Anastasia
AU - Shetty, Anoop
AU - Lee, Jack
AU - Nordsletten, David
AU - Rinaldi, Christopher Aldo
AU - Lamata de la Orden, Pablo
AU - Niederer, Steven
PY - 2017/2/10
Y1 - 2017/2/10
N2 - Myocardial stiffness is a valuable clinical biomarker for the monitoring and stratification of heart failure (HF). Cardiac finite element models provide a biomechanical framework for the assessment of stiffness through the determination of the myocardial constitutive model parameters. The reported parameter intercorrelations in popular constitutive relations, however, obstruct the unique estimation of material parameters and limit the reliable translation of this stiffness metric to clinical practice. Focusing on the role of the cost function (CF) in parameter identifiability, we investigate the performance of a set of geometric indices (based on displacements, strains, cavity volume, wall thickness and apicobasal dimension of the ventricle) and a novel CF derived from energy conservation. Our results, with a commonly used transversely isotropic material model (proposed by Guccione et al.), demonstrate that a single geometry-based CF is unable to uniquely constrain the parameter space. The energy-based CF, conversely, isolates one of the parameters and in conjunction with one of the geometric metrics provides a unique estimation of the parameter set. This gives rise to a new methodology for estimating myocardial material parameters based on the combination of deformation and energetics analysis. The accuracy of the pipeline is demonstrated in silico, and its robustness in vivo, in a total of 8 clinical data sets (7 HF and one control). The mean identified parameters of the Guccione material law were (Formula presented.) and (Formula presented.) ((Formula presented.), (Formula presented.), (Formula presented.)) for the HF cases and (Formula presented.) and (Formula presented.) ((Formula presented.), (Formula presented.), (Formula presented.)) for the healthy case.
AB - Myocardial stiffness is a valuable clinical biomarker for the monitoring and stratification of heart failure (HF). Cardiac finite element models provide a biomechanical framework for the assessment of stiffness through the determination of the myocardial constitutive model parameters. The reported parameter intercorrelations in popular constitutive relations, however, obstruct the unique estimation of material parameters and limit the reliable translation of this stiffness metric to clinical practice. Focusing on the role of the cost function (CF) in parameter identifiability, we investigate the performance of a set of geometric indices (based on displacements, strains, cavity volume, wall thickness and apicobasal dimension of the ventricle) and a novel CF derived from energy conservation. Our results, with a commonly used transversely isotropic material model (proposed by Guccione et al.), demonstrate that a single geometry-based CF is unable to uniquely constrain the parameter space. The energy-based CF, conversely, isolates one of the parameters and in conjunction with one of the geometric metrics provides a unique estimation of the parameter set. This gives rise to a new methodology for estimating myocardial material parameters based on the combination of deformation and energetics analysis. The accuracy of the pipeline is demonstrated in silico, and its robustness in vivo, in a total of 8 clinical data sets (7 HF and one control). The mean identified parameters of the Guccione material law were (Formula presented.) and (Formula presented.) ((Formula presented.), (Formula presented.), (Formula presented.)) for the HF cases and (Formula presented.) and (Formula presented.) ((Formula presented.), (Formula presented.), (Formula presented.)) for the healthy case.
KW - Myocardium
KW - Parameter estimation
KW - Passive constitutive equations
KW - Patient-specific modelling
UR - http://www.scopus.com/inward/record.url?scp=85012207964&partnerID=8YFLogxK
U2 - 10.1007/s10237-016-0865-3
DO - 10.1007/s10237-016-0865-3
M3 - Article
AN - SCOPUS:85012207964
SN - 1617-7959
SP - 1
EP - 18
JO - Biomechanics and Modeling in Mechanobiology
JF - Biomechanics and Modeling in Mechanobiology
ER -