Altered Structural Brain Networks in Tuberous Sclerosis Complex - PubMed (original) (raw)

Altered Structural Brain Networks in Tuberous Sclerosis Complex

Kiho Im et al. Cereb Cortex. 2016 May.

Abstract

Tuberous sclerosis complex (TSC) is characterized by benign hamartomas in multiple organs including the brain and its clinical phenotypes may be associated with abnormal neural connections. We aimed to provide the first detailed findings on disrupted structural brain networks in TSC patients. Structural whole-brain connectivity maps were constructed using structural and diffusion MRI in 20 TSC (age range: 3-24 years) and 20 typically developing (TD; 3-23 years) subjects. We assessed global (short- and long-association and interhemispheric fibers) and regional white matter connectivity, and performed graph theoretical analysis using gyral pattern- and atlas-based node parcellations. Significantly higher mean diffusivity (MD) was shown in TSC patients than in TD controls throughout the whole brain and positively correlated with tuber load severity. A significant increase in MD was mainly influenced by an increase in radial diffusivity. Furthermore, interhemispheric connectivity was particularly reduced in TSC, which leads to increased network segregation within hemispheres. TSC patients with developmental delay (DD) showed significantly higher MD than those without DD primarily in intrahemispheric connections. Our analysis allows non-biased determination of differential white matter involvement, which may provide better measures of "lesion load" and lead to a better understanding of disease mechanisms.

Keywords: brain networks; developmental delay; diffusion tensor imaging; structural connectivity; tuberous sclerosis complex.

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Figures

Figure 1.

Atlas-based parcellation using FreeSurfer and individual gyral pattern-based parcellation. The gyral node parcellation was used for short- and long range, and interhemispheric white matter connectivity as well as graph theoretical network analyses. The atlas-based parcellation was used for regional connectivity as well as graph theoretical analyses.

Figure 2.

Structural connections showing significantly lower FA and higher MD, RD, and AD in TSC patients compared with TD at the 0.05 level of corrected P. The number of statistically significant edges is mapped with a sphere of different sizes. IPG: inferior parietal gyrus; SPG: superior parietal gyrus; SMG: supramarginal gyrus; R: right; L: left.

Figure 3.

Structural connections showing significantly higher MD, RD, and AD in TSC patients with DD (DD+) compared with those without DD (DD−), and significant positive correlation between MD, RD, and AD and tuber severity in TSC patients at the 0.05 level of corrected P. The number of statistically significant edges is mapped with a sphere of different sizes. IPG: inferior parietal gyrus; R: right.

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Altered Structural Brain Networks in Tuberous Sclerosis Complex - PubMed (original) (raw)