Equipe Problèmes Inverses en electrophysiologie CARDiaque (EPICARD)

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Contact

Inria Bordeaux Sud-Ouest
200 rue de la vieille tour 33405 Talence Cedex, France
E-mail: nejib.zemzemi@lirima.fr; mourad.bellassoued@enit.utm.tn
Nejib Zemzemi’s web page
Mourad Bellassoued’s web page

About the team

EPICARD in few words

EPICARD is an associate team between the Carmen project at Inria and “Laboratoire de Modélisation Mathématique et Numérique dans les Sciences de l’Ingénieur ” (LAMSIN). The goal of this association is to develop new mathematical approaches for solving different inverse problems in cardiac electrophysiology.

Team members

The team regroups also researchers from LAMSIN MohammedV university and from Université Technologique de Compiègne.

From Inria: Mostfa Bendahmane, Yves Coudière, Jacques Henry, Amel Karoui, Pauline Migerditichan and Nejib Zemzemi

From LAMSIN: Abir Amri, Ben Abda Amel, Rabeb Chamekh, Henda El Fekih, Fadhel Jday, Nabil Gmati Moez Kallel, Jamila Lassoued, Moncef Mahjoub

From MohamedV university: Rajae Aboulaich, El Mahdi El Guarmah, Najib Fikal and Keltoum Chahour.

From UTC de Compiègne (Laboratoire de mathématiques appliquées de Compiègne): Faker Ben Belgacem and Faten Jelassi.

Epicard fifth year achievements

Fifth year activities

Epicard fourth year achievements

Fourth year activities

Epicard second year achievements

Second year activities

Epicard first year achievements

First year activities

Scientific Production

Publications HAL du labo/EPI 172042 de la collection LIRIMA

2018

Journal articles

titre
Numerical simulation of the fractional flow reserve (FFR)
auteur
Keltoum Chahour, Rajae Aboulaich, Abderrahmane Habbal, Cherif Abdelkhirane, Nejib Zemzemi
article
Mathematical Modelling of Natural Phenomena, EDP Sciences, In press, Special issue “Mathematical Modelling in Cardiology”
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01944566/file/mmnp180018_proof-1.pdf BibTex

2017

Conference papers

titre
Inverse Problem of Electrocardiography: estimating the location of cardiac isquemia in a 3D geometry
auteur
C.E. Chavez, Nejib Zemzemi, Yves Coudière, Felipe Alonso-Atienza, Diegó Alvarez
article
Functional Imaging and modelling of the heart (FIMH2015), Jun 2017, Maastricht, Netherlands. ⟨10.1007/978-3-319-20309-6_45⟩
Accès au texte intégral et bibtex
https://hal.archives-ouvertes.fr/hal-01222385/file/Carlos_FIMH.pdf BibTex
titre
New approach for solving electrocardiography imaging inverse problem with missing data on the body surface
auteur
Mohammed Addouche, Nadra Bouarroudj, Jacques Henry, Fadhel Jday, Nejib Zemzemi
article
Tendances des Applications Mathématiques en Tunisie, Algérie, Maroc 10-13 mai 2017, May 2017, Hammamet, Tunisia
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01567821/file/tamtam2017.pdf BibTex

Reports

titre
On the identification of multiple space dependent ionic parameters in cardiac electrophysiology modelling
auteur
Yassine Abidi, Mourad Bellassoued, Moncef Mahjoub, Nejib Zemzemi
article
[Research Report] INRIA. 2017
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01567714/file/ABZM3_version_16-06-17.pdf BibTex

Preprints, Working Papers, …

titre
Sensitivity of the electrocardiographic problem to multiple independent sources of uncertainty
auteur
Rajae Aboulaich, Najib Fikal, Emahdi El Guarmah, Nejib Zemzemi
article
2017
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01567700/file/elsarticle-template.pdf BibTex

2016

Journal articles

titre
Stochastic Finite Element Method for torso conductivity uncertainties quantification in electrocardiography inverse problem
auteur
Rajae Aboulaich, Najib Fikal, Emahdi El Guarmah, Nejib Zemzemi
article
Mathematical Modelling of Natural Phenomena, EDP Sciences, 2016, 11 (2), pp.1-19. ⟨10.1051/mmnp/201611201⟩
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01289144/file/mmnp-format-fikal.pdf BibTex
titre
Stability results for the parameter identification inverse problem in cardiac electrophysiology
auteur
Jamila Lassoued, Moncef Mahjoub, Nejib Zemzemi
article
Inverse Problems, IOP Publishing, 2016, 32, pp.1-31. ⟨10.1088/0266-5611/32/11/115002⟩
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01399373/file/Paper-Mahjoub-Moncef-soumission-Inverse-Problems-corrige.pdf BibTex

Conference papers

titre
Identification of sources for the bidomain equation using topological gradient
auteur
Jamila Lassoued, Moncef Mahjoub, Nejib Zemzemi
article
Colloque africain sur la recherche en informatique et mathématiques appliquées, CARI 2016, Oct 2016, Hammamet, France
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01402953/file/Papier_CAri.pdf BibTex
titre
Sensitivity of the electrocardiographic forward problem to the heart potential measuement noise and conductivity uncertainties
auteur
Rajae Aboulaich, Najib Fikal, El Mahdi Guarmah, Nejib Zemzemi
article
Colloque africain sur la recherche en informatique et mathématiques appliquées, CARI 2016, Oct 2016, Hammamet, Tunisia
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01402938/file/squelette-CARI2016.pdf BibTex
titre
Stability results for the parameter identification inverse problem in cardiac electrophysiology
auteur
Lassoued Jamila, Mahjoub Moncef, Nejib Zemzemi
article
PICOF (Problèmes Inverses, Contrôle et Optimisation de Formes), Jun 2016, Autrans, France
Accès au bibtex
BibTex
titre
A Nash-game approach to solve the Coupled problem of conductivity identification and data completion
auteur
Rabeb Chamekh, Abderrahmane Habbal, Moez Kallel, Nejib Zemzemi
article
PICOF (Problèmes Inverses, Contrôle et Optimisation de Formes), Jun 2016, Autrans, France
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01402976/file/abstract-picof-2016.pdf BibTex

2015

Conference papers

titre
Inverse Localization of Ischemia in a 3D Realistic Geometry: A Level Set Approach
auteur
Carlos E. Chavez, Felipe Alonso-Atienza, Nejib Zemzemi, Yves Coudière, Diegó Alvarez
article
Computing in cardiology, Sep 2015, Nice, France
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01241754/file/Carlos-Cinc2015.pdf BibTex
titre
Accuracy of Lead Removal vs Linear Interpolation in Non-Invasive Electrocardiographic Imaging (ECGI)
auteur
Laura Bear, Mark Potse, Josselin Duchateau, Nejib Zemzemi, Yves Coudière, Rémi Dubois
article
Computing in cardiology, Sep 2015, Nice, France
Accès au texte intégral et bibtex
https://hal.inria.fr/hal-01241752/file/Cinc2015-Laura.pdf BibTex
titre
Inverse problem in electrocardography via the factorization method of boundary value problems
auteur
Julien Bouyssier, Nejib Zemzemi, Jacques Henry
article
IEEE 12th International Symposium on Biomedical Imaging (ISBI), 2015, Apr 2015, New York, France. ⟨10.1109/ISBI.2015.7163979 ⟩
Accès au texte intégral et bibtex
https://hal.archives-ouvertes.fr/hal-01222401/file/ArticleISBI2015.pdf BibTex

Book sections

titre
Sensitivity of the Electrocardiography Inverse Solution to the Torso Conductivity Uncertainties
auteur
Nejib Zemzemi, Rajae Aboulaich, Najib Fikal, Emahdi El Guarmah
article
Hans van Assen; Peter Bovendeerd ; Tammo Delhaas. Functional Imaging and Modeling of the Heart, Lecture Notes in Computer Science (9126), ⟨Springer⟩, pp.475-483, 2015, 8th International Conference, FIMH 2015, Maastricht, The Netherlands, June 25-27, 2015. Proceedings, 978-3-319-20308-9. ⟨10.1007/978-3-319-20309-6_54⟩
Accès au texte intégral et bibtex
https://hal.archives-ouvertes.fr/hal-01222381/file/fimh.pdf https://hal.archives-ouvertes.fr/hal-01222381/file/fimh%20%281%29.pdf BibTex

Poster communications

titre
Sensitivity of the electrocardiography inverse solution to the torso conductivity uncertainties
auteur
Rajae Aboulaich, Najib Fikal, El Mahdi El Guarmah, Nejib Zemzemi
article
LIRYC scientific day, Jun 2015, Pessac, France
Accès au texte intégral et bibtex
https://hal.archives-ouvertes.fr/hal-01222404/file/poster.pdf BibTex
titre
New Mathematical approaches in Electrocardiography Imaging inverse problem
auteur
Nejib Zemzemi, Mark Potse, Laura Bear, Yves Coudière, Rémi Dubois, Jacques Henry, C Dallet, Josselin Duchateau, O Bernus, M Haïssaguerre
article
LIRYC scientific day, Jun 2015, Pessac, France
Accès au texte intégral et bibtex
https://hal.archives-ouvertes.fr/hal-01222406/file/LirycPoster.pdf BibTex

Medical context

Atrial fibrillation (AF) is the most common sustained heart arrhythmia. Ventricular fibrillations (VF) are more dangerous and are responsible for sudden cardiac death.
The LIRYC institute is one of six French university hospital institutions created in 2011 as part of the ”investments for the future” program (”Investissements d’avenir”) to boost medical research and innovation.
This institute, headed by Professor Michel Haissaguerre with clinicians from the University Hospital of Bordeaux and basic scientist teams is devoted to understanding the mechanism of AF and VF and developing new approaches to treat these cardiac pathologies. Carmen is an Inria team that is involved in the LIRYC institute by offering the modeling and simulation component of the project. One of the most used interventions to prevent and/ or stop VF and AF is radio-frequency ablation. This intervention requires an accurate targeting of the substrate to be ablated. The recent non-invasive technology used in guiding medical doctors to target these substrates is based on an inverse electrical mapping technique also known as electrocardiographic imaging (ECGI). With this approach, potentials on the outer (epicardial) surface of the heart are computed from potentials measured on the body surface using information on the geometry of the heart and the 3D locations of measured potentials. This is exactly the data completion Cauchy problem for elliptic equations. An ECGI mapping system was approved for use in Europe in 2011 and is available for clinical and basic science research at the LIRYC Institute in Bordeaux.
In this context, we would like to create a the EPICARD project, and the goal is to implement and test different mathematical approaches solving the ECGI problem but also to invent and design new mathematical approaches to study the problem differently than what has been done in the literature. In particular, physiologically detailed model personalization has not been considered in the literature mainly because of the mathematical and numerical challenge that it raises.

The ECGI procedure

One of the most recent heart imaging techniques introduced recently to the clinical industry is the electrocadiography imaging (ECGI). This technique allows a non-invasive reconstruction of the electrical potential on the heart surface based on the electrical potential measurement on the body surface and anatomical data of the torso. It has been a research topic for decades and it is now under clinical assessment in different leading hospitals around the world. ECGI provides very precious informations about the heart condition since it is able to provide refined spatial description of the electrical wave pathway and magnitude on the heart surface. This helps a lot in different clinical interventions like radio-frequency ablation usually used to stop atrial and ventricular arrhythmias. We work together with cardiologist from CHU de Bordeaux in order to improve the algorithm behind the inverse problem solving.

In order to solve the ECGI inverse problem many steps have to be taken into account: image segmentation, mesh generation, mathematical approaches, numerical algorithms and scientific visualization.

Image Segmentation and Mesh Generation

We use anathomical geometries provided by CHU de Bordeaux. Here is an exampmle of a CT scan of a 43 year old woman. We first segment the DICOM images, we identify the main regions in the torso domain: heart, lungs, bones, and the rest of the torso tissue. After segmentation, we use Tetgen MMG3D meshing Software in order to get a good quality of athetrahedral mesh.
CTscan-Mesh

Mathematical methods

The most widely used mathematical formulation used to solve ECGI inverse problem is a least square equation minimizing the gap between the measured ECGs and potentials mapped from the heart to the torso using a transfer matrix. This problem is ill posed since the transfer matrix it self could be a rectangular matrix. Many approaches have been used in the litterature to regularise the problem.
In this team project we aim to provide novel formulation of this inverse problem and compare them to the state-of-the-art procedure. We already have got promising results with the following methods:

  1. Iterative Kozlov- Maz’ya-Fomin (KMF) method .
  2. A domain decomposition approach for solving the Inverse problem in electrocardiography .
  3. A Steklov-Poincaré Variational Formulation of the Inverse Problem in Cardiac Electrophysiology .
  4. A Machine Learning Technique Regularization of the Inverse Problem in Cardiac Electrophysiology .
  5. Factorization of boundary problems method for solving ECGI .

Our aim is to build a library that allows comparing these methods to the methods develepped by the project team members and other approches in the littterature.

Numerical Algorithms

Numerical algorithms are computer implementation of the mathematical methods on the computational geometries.
They have to be very acccurate but also sufficiently fast in order to be used in clinical applications

Visualization

Numerical algorithms provide tables with numbers. The interpretation of this data is difficult without a good representation.
Visualization tools, like paraview, help in representing this data with images and movies that medical doctors could easily interpret.

Example of normal case

ComparisonSnapshot1

Example of a re-entree case

ComparisonSnapshot3

Gallery of preliminary results

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Click here for a movie show

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