Physics-informed neural network estimation of active material properties in time-dependent cardiac biomechanical models
This work addresses the problem of improving diagnosis and treatment planning for heart conditions like fibrosis by enabling more accurate parameter estimation from clinical imaging data, though it is incremental as it builds on existing PINN methods with specific enhancements.
The study tackled the challenge of estimating active stress parameters in cardiac biomechanics from imaging data by applying physics-informed neural networks (PINNs) in an in-silico setting, achieving reconstruction of active stress fields with high spatial resolution even in noisy conditions.
Active stress models in cardiac biomechanics account for the mechanical deformation caused by muscle activity, thus providing a link between the electrophysiological and mechanical properties of the tissue. The accurate assessment of active stress parameters is fundamental for a precise understanding of myocardial function but remains difficult to achieve in a clinical setting, especially when only displacement and strain data from medical imaging modalities are available. This work investigates, through an in-silico study, the application of physics-informed neural networks (PINNs) for inferring active contractility parameters in time-dependent cardiac biomechanical models from these types of imaging data. In particular, by parametrising the sought state and parameter field with two neural networks, respectively, and formulating an energy minimisation problem to search for the optimal network parameters, we are able to reconstruct in various settings active stress fields in the presence of noise and with a high spatial resolution. To this end, we also advance the vanilla PINN learning algorithm with the use of adaptive weighting schemes, ad-hoc regularisation strategies, Fourier features, and suitable network architectures. In addition, we thoroughly analyse the influence of the loss weights in the reconstruction of active stress parameters. Finally, we apply the method to the characterisation of tissue inhomogeneities and detection of fibrotic scars in myocardial tissue. This approach opens a new pathway to significantly improve the diagnosis, treatment planning, and management of heart conditions associated with cardiac fibrosis.