Sami Obaid1,2, Françcois Rheault2,3, Manon Edde2, Guido Guberman4, Etienne St-Onge2, Jasmeen Sidhu2, Alain Bouthillier5, Alessandro Daducci6, Dang Khoa Nguyen7, and Maxime Descoteaux2
1Department of Neurosciences, Université de Montréal, Montréal, Quebec, Canada, Montréal, QC, Canada, 2Sherbrooke Connectivity Imaging Lab (SCIL), Université de Sherbrooke, Sherbrooke, Quebec, Canada, Sherbrooke, QC, Canada, 3Electrical Engineering, Vanderbilt University, Nashville, TN, United States, Nashville, TN, United States, 4Department of Neurology and Neurosurgery, Faculty of Medicine, McGill University, Montreal, QC, Canada, Montreal, QC, Canada, 5Division of Neurosurgery, CHUM, Montréal, Quebec, Canada, Montreal, QC, Canada, 6Department of Computer Science, University of Verona, Verona, Italy, Verona, Italy, 7Service de Neurologie, CHUM, Montréal, Québec, Canada, Montreal, QC, Canada
1Department of Neurosciences, Université de Montréal, Montréal, Quebec, Canada, Montréal, QC, Canada, 2Sherbrooke Connectivity Imaging Lab (SCIL), Université de Sherbrooke, Sherbrooke, Quebec, Canada, Sherbrooke, QC, Canada, 3Electrical Engineering, Vanderbilt University, Nashville, TN, United States, Nashville, TN, United States, 4Department of Neurology and Neurosurgery, Faculty of Medicine, McGill University, Montreal, QC, Canada, Montreal, QC, Canada, 5Division of Neurosurgery, CHUM, Montréal, Quebec, Canada, Montreal, QC, Canada, 6Department of Computer Science, University of Verona, Verona, Italy, Verona, Italy, 7Service de Neurologie, CHUM, Montréal, Québec, Canada, Montreal, QC, Canada
Using a cutting-edge quantitative connectivity
pipeline incorporating surface-enhanced tractography and ‘connectivity
strength’-defining COMMIT weights, we observed a specific pattern of increased
‘connectivity strength’ in the epileptic network of operculo-insular epilepsy.
Figure 2. Illustration of a group comparison of
whole-brain COMMIT weights between of HCs and OIE. Multiple connections showed
significant alterations both ipsilaterally and contralaterally. Group comparisons
were performed using one-tailed t-tests. Significance was thresholded at p<0.001
uncorrected. Age and gender were accounted for in HCs whereas age,
gender, side of epileptic focus, duration of epilepsy and age of onset of
epilepsy were accounted for in OIE patients. Matrices in both HCs and OIE
patients were masked based on a similarity threshold calculated in HCs.
Figure
1. Flowchart. Raw images were processed using Tractoflow. The output of
Tractoflow and CIVET-calculated surfaces were used to build the tractogram
using SET. COMMIT filtering was then performed. In parallel, the Freesurfer-calculated
surfaces were used to generate Brainnetome parcels. The COMMIT-weighted
tractogram and Brainnetome parcellations were used to derive structural
connectivity matrices. Matrices of patients with right-sided OIE or TLE were
then side-flipped and bundles that were anatomically dissimilar between
controls were excluded in all matrices.
