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Fast Global Tractography for Sensitive MR Connectomics

English title Fast Global Tractography for Sensitive MR Connectomics
Applicant Thiran Jean-Philippe
Number 144529
Funding scheme Project funding (Div. I-III)
Research institution Laboratoire de traitement des signaux 5 EPFL - STI - IEL - LTS5
Institution of higher education EPF Lausanne - EPFL
Main discipline Information Technology
Start/End 01.10.2012 - 30.09.2014
Approved amount 113'118.00
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All Disciplines (2)

Discipline
Information Technology
Neurology, Psychiatry

Keywords (7)

connectomics; diffusion MRI; Tractography; brain connectivity; global optimization; Diffusion Spectrum Imaging; Gibbs sampling

Lay Summary (English)

Lead
Lay summary

Tractography (also called fiber tracking or fiber tracing) is a general term for methods to reconstruct fiber pathways in the white matter based on diffusion MR imaging. It offers a unique possibility to gain insight into the structure of the human brain non invasively and in vivo. The information won in this manner is not only of high value for visualization of the brain connectivity and segmentation of the brain into different functional areas, it also has the potential to provide essential information that can be exploited e.g. for neurosurgical planning or for better understanding major diseases such as multiple sclerosis, epilepsy, schizophrenia, brain plasticity after strokes etc. 

Tractography is thus the central tool in MR-based brain connectivity analysis, i.e. in MR connectomics. Although largely developed, tractography still mostly relies on local optimization methods, and remains therefore quite unstable and unreliable, especially for mapping non-dominant pathways and when used with advanced diffusion MR acquisition schemes such as High Angular Resolution Diffusion Imaging (HARDI) or Diffusion Spectrum Imaging (DSI). 

Recently, global tractography methods appeared. Although being promising, they suffer from major limitations, including prohibitive computational time. Moreover they are not adapted to be used with the most advanced acquisition scheme, namely DSI. 

In this project, we will develop a new global tractography algorithm, fully adapted to DSI and based on a new parametrization of the fiber curves, to reduce the number of parameters to estimate, and on advanced optimization schemes using Gibbs sampling, to find the optimal solution of the tractography. With this algorithm, we expect to improve significantly the accuracy and the stability of the brain connectivity analysis, and to be able to map subtle changes in the brain connectome. 

In terms of application, our global tractography method will be used to study global and local variation in brain connectivity in epileptic patients. It will allow the detection of subtle abnormalities and the tracking of neuronal fibers between any two cortical regions of the brain. Moreover, because the same patients are also investigated with electric source imaging and with EEG-fMRI, the connectivity maps will be directly compared to the functional data, providing a unique possibility to study structure and function in the same brain. 


This 2-year project has to be seen as a methodological complement and a direct contribution to the SNF SPUM project entitled “Imaging large scale neuronal networks in epilepsy”(SNF project nbr 33CM30-124089), coordinated by Prof. Margitta Seeck (Univ. Hospital of Geneva). While the clinical research will be performed in the SPUM project, our project will develop new methodological tools towards a better understanding of the neuronal network functioning in epilepsy, and far beyond, as a major contribution to brain connectivity analysis, i.e. to MR connectomics.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Anatomical Priors to improve Global Tractography
Lemkaddem Alia, Didrik Skiöldebrand, Dal Palú Alessandro, Thiran Jean-Philippe, Daducci Alessandro (2014), Anatomical Priors to improve Global Tractography, in The International Society for Magnetic Resonance in Medicine (ISMRM), Milan, ItalyISMRM, Milan.
Structural Graph Analysis of Left and Right Temporal Lobe Epilepsy using Diffusion Spectrum Imaging
Lemkaddem Alia, Daducci Alessandro, Lazeyras Francois, Seeck Margitta, Thiran Jean-Philippe (2014), Structural Graph Analysis of Left and Right Temporal Lobe Epilepsy using Diffusion Spectrum Imaging, in The International Society for Magnetic Resonance in Medicine (ISMRM), Milan, ItalyISMRM, Milan.
A convex optimization framework for global tractography
Daducci Alessandro, Dal Palú Alessandro, Lemkaddem Alia, Thiran Jean-Philippe (2013), A convex optimization framework for global tractography, in IEEE International Symposium on Biomedical Imaging: From Nano to Macro, San Francisco, CaliforniaIEEE, San Francisco.
Brain network analysis of patients with Temporal Lobe Epilepsy
Lemkaddem Alia, Vulliemoz Serge, Griffa Alessandra, Daducci Alessandro, Meskaldji Djalel Eddine, Lazeyras François, Seeck Margitta, Thiran Jean-Philippe (2013), Brain network analysis of patients with Temporal Lobe Epilepsy, in IEEE International Symposium on Biomedical Imaging: From Nano to Macro, San Francisco, CaliforniaIEEE, San Francisco.
Tracking the source of cerebellar epilepsy: hemifacial seizures associated with cerebellar cortical dysplasia.
Lascano Agustina M, Lemkaddem Alia, Granziera Cristina, Korff Christian M, Boex Colette, Jenny Benoit, Schmitt-Mechelke Thomas, Thiran Jean-Philippe, Garibotto Valentina, Vargas Maria Isabel, Schaller Karl, Seeck Margitta, Vulliemoz Serge (2013), Tracking the source of cerebellar epilepsy: hemifacial seizures associated with cerebellar cortical dysplasia., in Epilepsy research, 105(1-2), 245-9.
A multi-center study: intra-scan and inter-scan variability of diffusion spectrum imaging.
Lemkaddem A, Daducci A, Vulliemoz S, O'Brien K, Lazeyras F, Hauf M, Wiest R, Meuli R, Seeck M, Krueger G, Thiran J-P (2012), A multi-center study: intra-scan and inter-scan variability of diffusion spectrum imaging., in NeuroImage, 62(1), 87-94.
Altered structural connectivity in patients with medial temporal lobe epilepsy: A Diffusion Spectrum Imaging and Graph Analysis study
Lemkaddem Alia, Vulliemoz Serge, Griffa Alessandra, Daducci Alessandro, Seeck Margitta, Thiran Jean-Philippe (2012), Altered structural connectivity in patients with medial temporal lobe epilepsy: A Diffusion Spectrum Imaging and Graph Analysis study, in The International Society for Magnetic Resonance in Medicine (ISMRM), Melbourne, AustraliaISMRM, Melbourne.
The Connectome Mapper: An Open-Source Processing Pipeline to Map Connectomes with MRI
Daducci Alessandro, Gerhard Stephan, Griffa Alessandra, Lemkaddem Alia, Cammoun Leila, Gigandet Xavier, Meuli Reto, Hagmann Patric, Thiran Jean-Philippe (2012), The Connectome Mapper: An Open-Source Processing Pipeline to Map Connectomes with MRI, in PLOS ONE, 7(12), e48121.
Whole-brain structural connectivity in temporal lobe epilepsy: a Diffusion Spectrum Imaging study
Vulliemoz Serge, Lemkaddem Alia, Griffa Alessandra, Daducci Alessandro, Lazeyras François, Seeck Margitta, Thiran Jean-Philippe (2012), Whole-brain structural connectivity in temporal lobe epilepsy: a Diffusion Spectrum Imaging study, in 8th Annual Meeting of the Organization for Human Brain Mapping, Beijing, ChinaOHBM, Beijing, China.

Collaboration

Group / person Country
Types of collaboration
Hôpitaux Universitaires de Genève Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Centre Hospitalier Universitaire Vaudois (CHUV) Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Associated projects

Number Title Start Funding scheme
157063 Towards micro-structure-based tractography for quantitative brain connectivity analysis 01.10.2014 Project funding (Div. I-III)
157063 Towards micro-structure-based tractography for quantitative brain connectivity analysis 01.10.2014 Project funding (Div. I-III)
124089 Imaging large scale neuronal networks in epilepsy 01.05.2009 SPUM
150828 Development of Advanced Translational High-Field MRI 12.05.2014 R'EQUIP
121945 New methods for mapping and analysing large scale structural brain connectivity with MRI 01.08.2009 Project funding (Div. I-III)
170873 Exploring brain communication pathways by combining diffusion based quantitative structural connectivity and EEG source imaging : application to physiological and epileptic networks 01.03.2017 Sinergia

Abstract

Tractography (also called fiber tracking or fiber tracing) is a general term for methods to reconstruct fiber pathways in the white matter based on diffusion MR imaging. It offers a unique possibility to gain insight into the structure of the human brain noninvasively and in vivo. The information won in this manner is not only of high value for visualization of the brain connectivity and segmentation of the brain into different functional areas, it also has the potential to provide essential information that can be exploited e.g. for neurosurgical planning or for better understanding major diseases such as multiple sclerosis, epilepsy, schizophrenia, brain plasticity after strokes etc. Tractography is thus the central tool in MR-based brain connectivity analysis, i.e. in MR connectomics. Although largely developed, tractography still mostly relies on local optimisation methods, and remains therefore quite unstable and unreliable, especially for mapping non-dominant pathways and when used with advanced diffusion MR acquisition schemes such as High Angular Resolution Diffusion Imaging (HARDI) or Diffusion Spectrum Imaging (DSI). Recently, global tractgraphy methods appeared. Although being promising, they suffer from major limitations, including prohibitive computational time. Moreover they are not adapted to be used with the most advanced acquisition scheme, namely DSI. In this project, we will develop a new global tractography algorithm, fully adapted to DSI and based on a new parameterisation of the fiber curves, to reduce the number of parameters to estimate, and on advanced optimisation schemes using Gibbs sampling, to find the optimal solution of the tractography. With this algorithm, we expect to improve significantly the accuracy and the stability of the brain connectivity analysis, and to be able to map subtle changes in the brain connectome. In terms of application, our global tractography method will be used to study global and local variation in brain connectivity in epileptic patients. It will allow the detection of subtle abnormalities and the tracking of neuronal fibers between any two cortical regions of the brain. Moreover, because the same patients are also investigted with electric source imaging and with EEG-fMRI, the connectivity maps will be directly compared to the functional data, providing a unique possibility to study structure and function in the same brain. This 2-year project has to be seen as a methodological complement and a direct contribution to the SNF SPUM project entitled “Imaging large scale neuronal networks in epilepsy”(SNF project nbr 33CM30-124089), coordinated by Prof. Margitta Seeck (Univ. Hospital of Geneva). While the clinical research will be performed in the SPUM project, our project will develop new methodological tools towards a better understanding of the neuronal network functioning in epilepsy, and far beyond, as a major contribution to brain connectivity analysis, i.e. to MR connecomics.
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