Abnormal structural connectivity in the brain networks of children with hydrocephalus

Abstract

Increased intracranial pressure and ventriculomegaly in children with hydrocephalus are known to have adverse effects on white matter structure. This study seeks to investigate the impact of hydrocephalus on topological features of brain networks in children. The goal was to investigate structural network connectivity, at both global and regional levels, in the brains in children with hydrocephalus using graph theory analysis and diffusion tensor tractography. Three groups of children were included in the study (29 normally developing controls, 9 preoperative hydrocephalus patients, and 17 postoperative hydrocephalus patients). Graph theory analysis was applied to calculate the global network measures including small-worldness, normalized clustering coefficients, normalized characteristic path length, global efficiency, and modularity. Abnormalities in regional network parameters, including nodal degree, local efficiency, clustering coefficient, and betweenness centrality, were also compared between the two patients groups (separately) and the controls using two tailed t-test at significance level of p < 0.05 (corrected for multiple comparison). Children with hydrocephalus in both the preoperative and postoperative groups were found to have significantly lower small-worldness and lower normalized clustering coefficient than controls. Children with hydrocephalus in the postoperative group were also found to have significantly lower normalized characteristic path length and lower modularity. At regional level, significant group differences (or differences at trend level) in regional network measures were found between hydrocephalus patients and the controls in a series of brain regions including the medial occipital gyrus, medial frontal gyrus, thalamus, cingulate gyrus, lingual gyrus, rectal gyrus, caudate, cuneus, and insular. Our data showed that structural connectivity analysis using graph theory and diffusion tensor tractography is sensitive to detect abnormalities of brain network connectivity associated with hydrocephalus at both global and regional levels, thus providing a new avenue for potential diagnosis and prognosis tool for children with hydrocephalus.

Advanced Neuroimaging Techniques in Pediatric Hydrocephalus

“…While this study was preliminary in nature, it showed that structural connectivity analysis based on graph theory and DTI tractography is sensitive to the detection of abnormalities in whole-brain network connectivity in children with hydrocephalus at both regional and global levels [78] . The use of these techniques can be used to address such unique challenges as MRI interpretation and quantification of WM injury in children with surgically treated hydrocephalus with programmable shunts.…”

“…A recent study by Yuan et al [78] investigated the structural network connectivity at both the global and the regional level in children with hydrocephalus. While this study was preliminary in nature, it showed that structural connectivity analysis based on graph theory and DTI tractography is sensitive to the detection of abnormalities in whole-brain network connectivity in children with hydrocephalus at both regional and global levels [78] .…”

Left hemisphere structural connectivity abnormality in pediatric hydrocephalus patients following surgery

“…The data in the present study were selected from a prospective neuroimaging project of children treated for hydrocephalus ( Buckley et al, 2012 , Yuan et al, 2013 , Rajagopal et al, 2013 , Akbari et al, 2015 , Ragan et al, 2015 , Yuan et al, 2015 , Mangano et al, 2016 ). At the time of data analysis, 64 control children and 56 children with hydrocephalus were identified as eligible candidates for the present study.…”

“…More details about the initial site/scanner compatibility, its annual assessment, as well as the routine quality assurance procedures have been reported in previous work. ( Yuan et al, 2011 , Rajagopal et al, 2013 , Yuan et al, 2013 , Yuan et al, 2015 , Mangano et al, 2016 ).…”

“…This approach has recently emerged as a promising tool that provides information on the integrity of the structural connectivity of brain networks, at both global and regional levels ( Rubinov and Sporns, 2010 ). The application of this approach has generated many new perspectives in the study of neurological disorders, including a recent study of pediatric hydrocephalus ( Caeyenberghs et al, 2012 , Liu et al, 2014 , Pereira et al, 2015 , Sun et al, 2016 , Yuan et al, 2015 ). However, there is a unique difficulty in using this technique to study hydrocephalus in patients after their surgical treatment as many patients with hydrocephalus are treated by a shunting procedure that incorporates a programmable valve.…”