Sensitivity analysis of mesh warping and subsampling strategies for generating large scale electrophysiological simulation data
The analysis of large-scale simulation data from virtual populations can be effective to gain computational insight into disease mechanisms and treatment strategies, which can serve for generating hypotheses for and focusing subsequent clinical trials. This can be instrumental in shortening the critical path in medical product development and more cost-effective clinical trials. A previously published pipeline established point correspondence among volumetric meshes to enable meaningful statistics on cardiac electrophysiological simulations on the anatomical distribution of a large-scale virtual population. Thin Plate Splines (TPS), derived from surface deformations, were used to warp a tem…
An atlas- and data-driven approach to initializing reaction-diffusion systems in computer cardiac electrophysiology
The cardiac electrophysiology (EP) problem is governed by a nonlinear anisotropic reaction-diffusion system with a very rapidly varying reaction term associated with the transmembrane cell current. The nonlinearity associated with the cell models requires a stabilization process before any simulation is performed. More importantly, when used in a 3-dimensional (3D) anatomy, it is not sufficient to perform this stabilization on the basis of isolated cells only, since the coupling of the different cells through the tissue greatly modulates the dynamics of the system. Therefore, stabilization of the system must be performed on the entire 3D model. This work develops a novel procedure for the i…
Effect of Scar Development on Fast Electrophysiological Models of the Human Heart: In-Silico Study on Atlas-Based Virtual Populations
The main goal of this work is to study the effect of scar development in the electrophysiological function of the human left ventricle by statistically analyzing large-scale simulation data including hypertrophic and dilated hearts. Electrophysiological simulations are obtained by solving the classical Eikonal equation in both the ventricular tissue and a customized Purkinje system. This Purkinje system is obtained assuming a geodesic rule to connect different Purkinje-myocardial junctions into a tree-like structure. Infarction shape and function is modeled with taking into account the occlusion in coronary arteries. Infarct, core and border zones of the scar are estimated by calculating bl…
Atlas construction and image analysis using statistical cardiac models
International audience; This paper presents a brief overview of current trends in the construction of population and multi-modal heart atlases in our group and their application to atlas-based cardiac image analysis. The technical challenges around the construction of these atlases are organized around two main axes: groupwise image registration of anatomical, motion and fiber images and construction of statistical shape models. Application-wise, this paper focuses on the extraction of atlas-based biomarkers for the detection of local shape or motion abnormalities, addressing several cardiac applications where the extracted information is used to study and grade different pathologies. The p…
Influence of geometric variations on LV activation times: A study on an atlas-based virtual population
We present the fully automated pipeline we have developed to obtain electrophysiological simulations of the heart on a large atlas-based virtual population. This virtual population was generated from a statistical model of left ventricular geometry, represented by a surface model. Correspondence between tetrahedralized volumetric meshes was obtained using Thin Plate Spline warps. Simulations are based on the fast solving of Eikonal equations, and stimulation sites correspond to physiological activation. We report variations of total activation time introduced by geometry, as well as variations in the location of last activation. The obtained results suggest that the total activation time ha…