Personnel
Overall Objectives
Research Program
Highlights of the Year
New Software and Platforms
New Results
Bilateral Contracts and Grants with Industry
Partnerships and Cooperations
Dissemination
Bibliography
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Section: New Results

Medical Image Analysis

Segmentation and Anatomical Variability of the Cochlea from Medical Images

Participants : Thomas Demarcy [Correspondant] , Hervé Delingette, Charles Raffaelli [CHU, Nice] , Clair Vandersteen [IUFC, Nice] , Dan Gnansia [Oticon Medical] , Nicholas Ayache.

This work is supported by the National Association for Research in Technology (ANRT) through the CIFRE Grant 2013-1165 and Oticon Medical (Vallauris). This work is a collaboration with the Department of Ear Nose Throat Surgery (IUFC, Nice) and the Nice University Hospital (CHU).

image segmentation ; surgery planning ; shape modelling ; anatomical variability ; cochlear implant ; temporal bone

Figure 1. Cochlear implant electrode-array position (white) with respect to scala tympani (blue) and scala vestibuli (orange)
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Prediction of Post-Ablation Outcome in Atrial Fibrillation Using Shape Parameterization and Partial Least Squares Regression

Participants : Shuman Jia [Correspondent] , Claudia Camaioni, Marc Michel Rohe, Pierre Jaïs, Xavier Pennec, Hubert Cochet, Maxime Sermesant.

The authors acknowledge the partial funding by the Agence Nationale de la Recherche (ANR)/ERA CoSysMedSysAFib and ANR MIGAT projects.

We proposed an application of diffeomorphometry and partial least squares regression to address the problem of post-ablation outcome in atrial fibrillation.

As illustrated in Fig. 2, we computed a template of left atrial shape in control group and then established point-to-point correspondence between patient-specific shapes and the template. The diffeomorphic deformations are encoded and applied in partial least squares regression to predict ablation success, which outperformed the left atrial volume index.

Figure 2. Extraction of remodeling information vs. recurrence. (a) average shape in control group; (b) deformation from the template to patient-specific shapes; (c) deformation mode correlated with recurrence.
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Cardiac Imaging and Machine Learning for Electrostructural Tomography

Participants : Tania Marina Bacoyannis [Correspondent] , Hubert Cochet [IHU Liryc, Bordeaux] , Maxime Sermesant.

This work is funded within the ERC Project ECSTATIC from the IHU Liryc, in Bordeaux.

Machine Learning, Cardiac modeling, Personalised simulation, Inverse problem of ECG, Electrical simulation, Inverse problem.

By using non-invasive electrical data (Body Surface Potential Mapping), we aim to develop a machine learning approach that can improve electrophysiological cardiac modeling in order to improve diagnosis and predict the response to therapy. This project involves measured and simulated data. For example, we processed experimental data provided by the IHU Liryc, gathered during an experiment on an healthy pig's heart (Figure  3). The simulated potentials appeared to be close to the measurements (Figure  4). The short-term goal is to reconstruct semi-automatically the simulated personalized activation maps.

Figure 3. (a) Torso- tank experimental setup with perfused pig heart,(b) Representation of the experimental Torso for BSPM registration of the healthy pig heart, Torso's electrodes and the estimated activation map
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Figure 4. Example of BSPM signals on the Torso's electrode number 82
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VT-Scan: image based modelling of cardiac electrophysiology to guide catheter radiofrequency ablation of re-entrant ventricular tachycardia

Participants : Nicolas Cedilnik [Correspondent] , Maxime Sermesant, Hubert Cochet, Pierre Jaïs, Frédéric Sacher.

This work was funded by IHU Liryc, Bordeaux.

cardiac electrophysiology modelling, cardiac imaging, ventricular tachycardia, catheter ablation, arrhythmia

Figure 5. Example of a patient-specific simulation of a proven re-entrant wavefront propagation pattern. [Left] CT-measured myocardial wall thickness, projected on a CT-derived 3D mesh. [Middle] Myocardial activation simulation result using our framework. [Right] Activation recorded during a ventricular tachycardia catheter ablation
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Deep Learning for Tumor Segmentation

Participants : Pawel Mlynarski [Correspondent] , Nicholas Ayache, Hervé Delingette, Antonio Criminisi [MSR] .

This work is funded by Inria-Microsoft joint center and is done in cooperation with Microsoft Research in Cambridge.

deep learning, semi-supervised learning, segmentation, MRI, tumors

Figure 6. Left: axial slice of a brain MR image presenting a malignant tumor. Right: GT truth (red contour) vs segmentation produced by our semi-supervised method.
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Figure 7. Multimodal MR and the multi-class tumor segmentation produced by our system.
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Learning Brain Alterations in Multiple Sclerosis from Multimodal Neuroimaging Data

Participants : Wen Wei [Correspondent] , Nicholas Ayache [Inria] , Olivier Colliot [ARAMIS] .

Multiple Sclerosis, MRI, PET

Multiple sclerosis (MS) is a demyelinating and inflammatory disease of the central nervous system . The goal of this topic is to develop a machine learning approach that can predict different types of PET-derived brain alterations using multiple local and regional MRI measures for MS patients. Figure  8 shows an example of multiple MRI pulse sequences for MS studies.

Figure 8. Proton density (PD), T1 spin-echo (T1SE), T1-w, T2-w, double inversion recovery (DIR) weighted images are used for MS studies.
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Robust and 3D-Consistent Cardiac Segmentation by Deep Learning

Participants : Qiao Zheng [Correspondent] , Hervé Delingette [Inria] , Nicolas Duchateau [Université Claude Bernard Lyon 1] , Nicholas Ayache [Inria] .

Cardiac Segmentation, Deep Learning, MRI, Robustness, Consistency

We propose a method based on deep learning to perform cardiac segmentation on short axis MRI image stacks. An example of segmentation is presented in Figure 9. The method is trained on a large database and then tested on other state-of-the-art cohorts. Results comparable or even better than the state-of-the-art in terms of distance measures are achieved. They prove the contribution of our method to enhance spatial consistency, and its generalization ability to unseen cases even from other databases.

Figure 9. An example of cardiac segmentation.
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Joint analysis of radiomic and metabolomic features to improve diagnosis and therapy in oncology

Participants : Fanny Orlhac [Correspondent] , Charles Bouveyron, Hervé Delingette, Nicholas Ayache, Olivier Humbert [CAL] , Jacques Darcourt [CAL] , Thierry Pourcher [CEA] , Fanny Vandenbos [CHU Nice] .

Inria postdoctoral fellowship for 16 months

Radiomics, Metabolomics, Statistical learning

This work is done in collaboration with the Centre Antoine Lacassagne and the TIRO team (Transporter in Imagery and Radiotherapy for Oncology, CEA-UNS) located in Nice.

Figure 10. Joint analysis of radiomic and metabolomic features.
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Heart & Brain: discovering the link between cardiovascular pathologies and neurodegeneration through biophysical and statistical models of cardiac and brain images.

Participants : Jaume Banús Cobo [Correspondent] , Maxime Sermesant, Marco Lorenzi.

Uinversité Côte d'Azur (UCA)

Lumped models - Medical Imaging - Biophysical simulation - Machine learning

The project aims at developing a computational model of the relationship between cardiac function and brain damage from large‐scale clinical databases of multi‐modal and multi‐organ medical images. We will use advanced statistical learning tools for discovering relevant imaging features related to cardiac dysfunction and brain damage from large datasets of medical images and clinical information; these measurements will be combined within a unified mechanistic framework to understand and validate the relationship between cardiac function, vascular pathology and brain damage. The goal is to provide an unprecedented instrument for the in‐vivo assessment of latent neurodegenerative conditions in the general population, and will be validated with respect to established indices of cognitive decline and to specific sub‐population for which the ground truth is known.

Figure 11. a) Aortic valve flow imaging, view obtained from the plane represented in the left ventricular outflow tract (LVOT) cine b); c) T2 FLAIR image in which white matter hyperintensities (WMHs) are visible.
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Statistical learning on large databases of heterogeneous imaging, cognitive and behavioural data

Participants : Luigi Antelmi [Correspondant] , Marco Lorenzi, Nicholas Ayache, Valeria Manera, Philippe Robert.

statistical learning, neuroimaging, big data, multimodal

The aim of our work is to develop scalable learning models for the joint analysis of heterogeneous biomedical data. The project will be applied to the investigation of neurological disorders from collections of brain imaging, body sensors, biological and clinical data available in current large-scale health databases. The resulting methodological framework will be tested on the UK Biobank, as well as on pathology-specific clinical data, as provided by the ADNI (http://adni.loni.usc.edu/), or INSIGHT (http://alzheimer-recherche.org/9248/etude-insight/) initiatives.

From the methodological perspective, the project will focus on the development of computationally efficient formulations of probabilistic latent variable models. These approaches will highlight meaningful relationship among biomarkers that will be used to develop optimal strategies for disease quantification and prediction (Fig. 12).

The research is within the MNC3 initiative (Médecine Numérique: Cerveau, Cognition, Comportement) funded by Université Côte d'Azur (UCA), and will be performed in collaboration with the Institut Claude Pompidou (CHU of Nice).

Figure 12. Adopted framework: development of computationally efficient formulations of probabilistic latent variable models to highlight meaningful relationship among biomarkers for disease quantification and prediction.
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Robust non-rigid registration through agent-based action learning

Participants : Julian Krebs [Correspondent] , Hervé Delingette, Tommaso Mansi [Siemens [Siemens Healthineers, Medical Imaging Technologies] , Nicholas Ayache.

This PhD is carried out between the Asclepios research group, Inria Sophia Antipolis and Medical Imaging Technologies, Siemens Healthineers, Princeton, New Jersey, USA.

Deformable Registration, Deep Learning, Reinforcement Learning

We developed a deep learning-based approach for organ-specific deformable registration in 3-D [39] by:

Improved performance has been demonstrated with respect to traditional algorithms.

Figure 13. Dual-stream network used for the agent's action estimations including single-stage Markov Decision Process for testing (blue background).
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