Alterations in the metabolic networks of temporal lobe epilepsy patients: A graph theoretical analysis using FDG-PET

Shim, Hye Kyung; Lee, Ho‐Joon; Kim, Sung Eun; Lee, Ki Young; Park, Seong-Ho; Park, Kang Min

doi:10.1016/j.nicl.2020.102349

Cited by 25 publications

(24 citation statements)

References 39 publications

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“…Thus, these results indicate that TLE patients with HS carry a more disconnected functional brain network with a decreased integration than those without HS. The results are consistent with our recent work, demonstrating more severe alterations in metabolic networks based on FDG‐PET in TLE patients with HS than in those without HS and healthy controls 21 . Furthermore, Coan et al.…”

Section: Discussionsupporting

confidence: 93%

“…Next, using the BRAPH program, we created a weighted connectivity matrix based on the partial correlation and the CBF of the regions with corrections of covariates, including age and sex, and calculated the global and local network measures from the connectivity matrix. We already described the detailed method to obtain the network measures using BRAPH program in our previous studies 21,22 …”

Section: Methodsmentioning

confidence: 99%

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Temporal lobe epilepsy with or without hippocampal sclerosis: Structural and functional connectivity using advanced MRI techniques

Lee

Kim

et al. 2021

Journal of Neuroimaging

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Background and Purpose The aim of this study was to investigate the differences in structural connectivity based on diffusion tensor imaging (DTI) and functional connectivity based on arterial spin labeling (ASL) MRI between temporal lobe epilepsy (TLE) patients with and without hippocampal sclerosis (HS). Methods We enrolled 50 patients with TLE, including 25 patients with HS and 25 patients without HS, who underwent brain MRI, including DTI and ASL. We calculated the network parameters of structural connectivity based on DTI and functional connectivity based on ASL using a graph theoretical analysis. The parameters included global network measures (radius, diameter, characteristic path length, global efficiency, local efficiency, mean clustering coefficient, transitivity, assortative coefficient, and small‐worldness index) and a local network measure (betweenness centrality). Results The global and local network measures of structural connectivity were not different between TLE patients with and without HS. However, significant differences in functional connectivity existed between the two groups. The radius and diameter of the global network measures in the TLE patients with HS were significantly increased compared with those without HS (4.140 vs. 3.140, p = 0.045; 6.812 vs. 5.132, p = 0.049; respectively). No differences were detected between other global network measures of functional connectivity and local network measure. Conclusions Significant differences in global network measures of functional connectivity based on ASL existed between TLE patients with and without HS. These findings suggest that TLE patients with HS exhibit a more disconnected functional brain network than those without HS.

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Section: Discussionsupporting

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Temporal lobe epilepsy with or without hippocampal sclerosis: Structural and functional connectivity using advanced MRI techniques

Lee

Kim

et al. 2021

Journal of Neuroimaging

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“…Brain networks constructed from regional covariance estimation based on PET have gained particular attention in terms of metabolic networks. Recently, we have demonstrated changes in metabolic networks based on FDG‐PET using graph theoretical analysis in TLE patients, and found more severe alterations in TLE patients with HS than in those without HS and healthy controls 18 . Although some studies have suggested that graph theoretical analysis to reveal brain networks using several modalities, such as MRI, EEG, or MEG in TLE patients with HS, can predict seizure free following surgery, 19–21 there have been no studies regarding metabolic networks based on FDG‐PET for predicting surgical outcomes at the group level.…”

Section: Introductionmentioning

confidence: 99%

Metabolic network is related to surgical outcome in temporal lobe epilepsy with hippocampal sclerosis: A brain FDG‐PET study

Cho

Park

Lee

et al. 2021

Journal of Neuroimaging

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Background and Purpose The aim of this study was to investigate differences in metabolic networks based on preoperative fluorodeoxyglucose (FDG)‐positron emission tomography (PET) in temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS) between patients with complete seizure‐free (SF) and those with noncomplete seizure‐free (non‐SF) after anterior temporal lobectomy. Methods This study was retrospectively performed at a tertiary hospital. We recruited pathologically confirmed 75 TLE patients with HS who underwent preoperative FDG‐PET. All patients underwent a standard anterior temporal lobectomy. The surgical outcome was evaluated at least 12 months after surgery, and we divided the subjects into patients with SF (International League Against Epilepsy [ILAE] class I) and those with non‐SF (ILAE class II‐VI). We evaluated the metabolic network using graph theoretical analysis based on FDG‐PET. We investigated the differences in network measures between the two groups. Results Of the 75 TLE patients with HS, 32 patients (42.6%) had SF, whereas 43 patients (57.3%) had non‐SF. There were significant differences in global metabolic networks according to surgical outcomes. The patients with SF had a lower assortative coefficient than those with non‐SF (–0.020 vs. –0.009, p = .044). We also found widespread regional differences in local metabolic networks according to surgical outcomes. Conclusion Our study demonstrates significant differences in preoperative metabolic networks based on FDG‐PET in TLE patients with HS according to surgical outcomes. This work introduces a metabolic network based on FDG‐PET and can be used as a potential tool for predicting surgical outcome in TLE patients with HS.

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“…The term metabolic connectivity refers to interrelations between metabolic (FDG) measurements in different brain regions [1]. This approach was shown to yield valuable knowledge on substrates of cognitive reserve [2,3], working memory [4,5], impulse control [6], as well as on pathophysiology and diagnosis of neurodegenerative [7][8][9][10] and non-neurodegenerative disorders [11,12]. However, it is still unclear how MC is related to actual structural connectivity, i.e., connectivity through white matter fiber tracts.…”

Section: Introductionmentioning

confidence: 99%

Mapping covariance in brain FDG uptake to structural connectivity

Yakushev

Ripp

Wang³

et al. 2021

Eur J Nucl Med Mol Imaging

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Purpose Inter-subject covariance of regional 18F-fluorodeoxyglucose (FDG) PET measures (FDGcov) as proxy of brain connectivity has been gaining an increasing acceptance in the community. Yet, it is still unclear to what extent FDGcov is underlied by actual structural connectivity via white matter fiber tracts. In this study, we quantified the degree of spatial overlap between FDGcov and structural connectivity networks. Methods We retrospectively analyzed neuroimaging data from 303 subjects, both patients with suspected neurodegenerative disorders and healthy individuals. For each subject, structural magnetic resonance, diffusion tensor imaging, and FDG-PET data were available. The images were spatially normalized to a standard space and segmented into 62 anatomical regions using a probabilistic atlas. Sparse inverse covariance estimation was employed to estimate FDGcov. Structural connectivity was measured by streamline tractography through fiber assignment by continuous tracking. Results For the whole brain, 55% of detected connections were found to be convergent, i.e., present in both FDGcov and structural networks. This metric for random networks was significantly lower, i.e., 12%. Convergent were 80% of intralobe connections and only 30% of interhemispheric interlobe connections. Conclusion Structural connectivity via white matter fiber tracts is a relevant substrate of FDGcov, underlying around a half of connections at the whole brain level. Short-range white matter tracts appear to be a major substrate of intralobe FDGcov connections.

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Alterations in the metabolic networks of temporal lobe epilepsy patients: A graph theoretical analysis using FDG-PET

Cited by 25 publications

References 39 publications

Temporal lobe epilepsy with or without hippocampal sclerosis: Structural and functional connectivity using advanced MRI techniques

Temporal lobe epilepsy with or without hippocampal sclerosis: Structural and functional connectivity using advanced MRI techniques

Metabolic network is related to surgical outcome in temporal lobe epilepsy with hippocampal sclerosis: A brain FDG‐PET study

Mapping covariance in brain FDG uptake to structural connectivity

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