tissue micro-structure; Diffusion MRI; convex optimization; Connectomics; tractography; Medical image processing
Maier-Hein Klaus H., Neher Peter F., Houde Jean-Christophe, Garyfallidis Eleftherios, Zhong Jidan, Chamberland Maxime, Yeh Fang-Cheng, Lin Ying-Chia, Ji Qing, Reddick Wilburn E., Glass John O., Chen David Qixiang, Feng Yuanjing, Gao Chengfeng, Wu Ye, Ma Jieyan, Renjie H., Li Qiang, Westin Carl-Fredrik, Deslauriers-Gauthier Samuel, González J. Omar Ocegueda, Paquette Michael, St-Jean Samuel, et al. (2017), The challenge of mapping the human connectome based on diffusion tractography, in
Nature Communications, 8(1), 1349-1349.
Barakovic Muhamed, Romascano David Paul Roger, Girard Gabriel, Descoteaux Maxime, Thiran Jean-Philippe, Daducci Alessandro (2017), In-vivo Bundle-Specific Axon Diameter Distributions Estimation across the Corpus Callosum, in
25th annual meeting of the International Society for Magnetic Resonance in Medicine ({ISMRM}), Honolulu, Hawaii, USA.
Romascano David Paul Roger, Barakovic Muhamed, Auría Rasclosa Anna, Dyrby Tim B., Thiran Jean-Philippe, Daducci Alessandro (2017), Orientation invariant and non-parametric Axon Diameter Distribution mapping using {PGSE} and regularized discrete linear modeling, in
Proceedings of the 24th annual meeting of the International Society for Magnetic Resonance in Medici, Honolulu, Hawaii, USA.
Barakovic Muhamed, Romascano David Paul Roger, Girard Gabriel, Descoteaux Maxime, Thiran Jean-Philippe, Daducci Alessandro (2017), When does a volume of a bundle achieve saturation? A microstructure informed tractography study, in
25th annual meeting of the International Society for Magnetic Resonance in Medicine ({ISMRM}).
Daducci Alessandro, Dal Palú Alessandro, Descoteaux Maxime, Thiran Jean-Philippe (2016), Microstructure Informed Tractography: Pitfalls and Open Challenges, in
Frontiers in Neuroscience, 10, 247-247.
Barakovic Muhamed, Romascano David Paul Roger, Dyrby Tim B., Alexander Daniel C., Thiran Jean-Philippe, Daducci Alessandro (2016), Assessment of bundle-specific axon diameter distributions using diffusion {MRI} tractography, in
22nd Annual Meeting of the Organization for Human Brain Mapping.
Auría Rasclosa Anna, Romascano David Paul Roger, Canales-Rodriguez Erick J., Dyrby Tim B., Alexander Daniel C., Thiran Jean-Philippe, Wiaux Yves, Daducci Alessandro (2016), Reducing acquisition time for microstructure imaging with spatially-regularized global optimization, in
22nd Annual Meeting of the Organization for Human Brain Mapping ({OHBM}).
Auría Rasclosa Anna, Romascano David Paul Roger, Canales-Rodriguez Eric, Wiaux Yves, Dirby T. B., Alexander Daniel, Thiran Jean-Philippe, Daducci Alessandro (2015), Accelerated Microstructure Imaging via Convex Optimisation for regions with multiple fibres ({AMICO}x), in
{IEEE} International Conference on Image Processing 2015, Quebec City, Quebec, Canada.
Daducci Alessandro, Canales-Rodríguez Erick J., Zhang Hui, Dyrby Tim B., Alexander Daniel C., Thiran Jean-Philippe (2015), Accelerated Microstructure Imaging via Convex Optimization (AMICO) from diffusion MRI data, in
NeuroImage, 105, 32-44.
Daducci Alessandro, Dal Palu Alessandro, Lemkaddem Alia, Thiran Jean-Philippe (2015), COMMIT: Convex Optimization Modeling for Microstructure Informed Tractography, in
IEEE Transactions on Medical Imaging, 34(1), 246-257.
Griffa Alessandra, Baumann Philipp S, Ferrari Carina, Eric Tanja, Conus Philippe, Do Kim Q, Thiran Jean-Philippe, Hagmann Patric (2015), Diffusion spectrum imaging connectomics: a biomarker for staging in psychotic disorders, in
23rd International Symposium on Magnetic Resonance in Medicine ({ISMRM}).
Daducci Alessandro, Canales-Rodríguez Erick Jorge, Descoteaux Maxime, Garyfallidis Eleftherios, Gur Yaniv, Lin Ying-Chia, Mani Merry, Merlet Sylvain, Paquette Michael, Ramirez-Manzanares Alonso, Reisert Marco, Rodrigues Paulo Reis, Sepehrband Farshid, Jacob Mathews, Caruyer Emmanuel, Choupan Jeiran, Deriche Rachid, Menegaz Gloria, Prckovska Vesna, Rivera Mariano, Wiaux Yves, Thiran Jean-Philippe (2014), Quantitative comparison of reconstruction methods for intra-voxel fiber recovery from diffusion {MRI}, in
{IEEE} Transactions on Medical Imaging, 33(2), 384-399.
Diffusion magnetic resonance imaging (MRI) is a unique imaging modality because of its sensitivity to the microscopic movement of water molecules, i.e. Brownian motion, in biological tissues. By characterizing the anisotropy of this random diffusion process in the cerebral white matter, it is possible to infer at the macroscopic level the major neuronal pathways of the brain by means of so-called tractography algorithms. This ability to probe in-vivo the structural wiring of the nervous system with diffusion MRI (a.k.a. connectomics) is of utmost importance in a clinical perspective as it allows, for instance, to monitor the plasticity of the brain and the recovery after a stroke event or the progress of degenerative processes in neurodegenerative diseases.Despite connectomics offers an exquisite tool to investigate non-invasively the architecture of the neuronal connections of the brain, the reconstructions recovered with existing algorithms are not really quantitative. In fact, the information recovered by diffusion MR tractography is orders of magnitude coarser than the actual size of the axons and each of the recovered tracts represents an unspecified set of coherent real fibers. Consequently, the measures of structural connectivity between different brain regions estimated with existing tractography algorithms are only indirectly related to the actual properties of the underlying neuronal connections. On the other hand, diffusion MRI is actually a quantitative modality by nature and several techniques have recently appeared to estimate biological micro-structural properties of the neuronal tissue, such as the average diameter of the axons in each imaging voxel. However, fiber-tracking and tissue micro-structure estimation have been considered so far as two separate problems. As a consequence, to date, nothing can be inferred from diffusion MRI on the micro-structure of the fascicles themselves, ergo today connectomics analyses are not truly quantitative.In this project, we will develop a novel framework to re-establish the link between tractography and tissue micro-structure, opening the door for quantitative and biologically-oriented assessment of the structural connectivity of the brain. Multidisciplinary research will be required to accomplishment our objectives, such as (i) advanced signal processing for the methodological development of a mathematical framework recently proposed by our group (attached to this proposal), (ii) diffusion MRI modeling to reach the proper sensitivity to tracts with different axonal diameters, and (iii) neuroanatomy to validate our approach by comparing ex-vivo acquisitions on fixed samples with histology. With this framework, we expect to drastically improve the sensitivity and specificity of existing connectomics techniques, and to be able to detect subtle changes in brain connectivity due to pathologic conditions.The long-term experience of the applicants in the fields of diffusion MRI and advanced signal processing, together with the recognized expertize in MRI acquisition and histology granted by established collaborations with external partners, will set the ideal grounds towards the expected breakthroughs in quantitative and biologically-oriented brain connectivity analyses.