Group comparison of cortical fiber connectivity map: An application between post-stroke patients and healthy subjects

Structural connectome measurement combined with diffusion magnetic resonance imaging (MRI) and tractography allows generation of a whole-brain connectome. However, current cortical structural connectivity (SC) measurements have not been well combined with the vertex-wise multi-subjects statistical analysis. The aim of this study was to examine the feasibility of using group comparison vertex-wise analysis for cortical SC measurement. A fiber connectivity density (FiCD) method based on a combination of a diffusion fiber tracking technique and cortical surface-based analysis was used to measure the whole-brain cortical SC map (FiCD map). A public MRI dataset (GigaDB) was employed to evaluate the reproducibility of the FiCD method. For group comparison, 14 post-stroke patients (mean age, 68.36 ± 7.33 y) and 19 healthy participants (mean age, 66.84 ± 8.58 y) had FiCD measurement. The intergroup comparison of the FiCD map was performed using vertex-wise multi-subject statistical analysis. Reliability testing showed the mean intra- and inter-subject FiCD variability was 3.51 ± 2.12% and 19.44 ± 4.79%, respectively. The group comparison of the whole-brain FiCD identified cortical regions with altered FiCD values, and there was a spatial consistency between the cortical clusters with low FiCD values and the subcortical lesions of patients. This study demonstrated the feasibility of vertex-wise group comparison for evaluating cortical fiber connectivity density. The FiCD method has good intra- and inter-individual reproducibility, and accurately reflects the affected cortical regions in post-stroke patients. This method may be helpful for neuroscience research.