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

Abstract

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.

Metabolic connectivity is associated with seizure outcome in surgically treated temporal lobe epilepsies: A 18F-FDG PET seed correlation analysis

“…One of the major findings of the present study is the increased connectivity within the operated temporal lobe observed in the > IA groups compared to the IA groups in both left and right TLE (clusters of 7.5 vs 3.3 cm 3 and 2.6 cm 3 vs 2.2 cm 3 for left and right TLE respectively, Table 3 ). This is consistent with recent metabolic connectivity studies based on graphical analyses, gathering left-lateralized and right-lateralized patients, that reported higher functional connectivity in patients who were not seizure-free ( Cho et al, 2022 , Ren et al, 2021 , Yu et al, 2018 ). The main hypothesis is that the persistent seizure group has over-excitatory brain activity compared to seizure-free patients as indicated by strengthened brain connections, allowing seizures to occur and to propagate more readily.…”

“…Thus, even after anterior temporal lobectomy and removal of the epileptogenic zone, the epileptogenic network may persist in patients with increased connectivity with these network differences contributing to the surgical outcomes of TLE patients. Indeed, Cho et al observed a more increased assortative coefficient in non-seizure-free patients, implicating that the epileptogenic network is more robust to removal of the epileptogenic zone ( Cho et al, 2022 ). In our study, these findings cannot be explained by the longer duration of disease observed in IA patients compared to > IA patients since it may have led to stronger connections in IA patients.…”

“…Metabolic activity estimated by PET allows to circumvent issues related to neurovascular coupling inherent to the blood oxygen level-dependent MRI approach. Only very few studies that assess the metabolic connectivity in temporal lobe epilepsy have been published to date ( Vanicek et al, 2016 , Wang et al, 2019 , Shim et al, 2020 , Ren et al, 2021 , Zhu et al, 2022 , Cho et al, 2022 ). They predominantly involve a small number of epilepsy patients, gather left and right epilepsies, and use a metabolic connectivity approach based on graph theory analyses, without any a priori hypotheses, which potentially increases the number of false positives correlations obtained ( Sala & Perani, 2019 ).…”

Mammillary Body Atrophy in Temporal Lobe Epilepsy With Hippocampal Sclerosis

“… 28 Some studies have assessed the association between surgical outcomes and MRI markers in TLE with HS. 29 30 31 One of the purposes of our study was to determine the potential clinical significance of MB atrophy in predicting surgical outcomes. Surgical outcomes following anterior temporal lobectomy were good in 58% of patients in the present study, which was similar to previous reports.…”

The effects of hemodialysis on the functional brain connectivity in patients with end–stage renal disease: A functional near–infrared spectroscopy study

“…The most commonly used modality to determine functional connectivity is rs-fMRI;(6, 7) however, there are also other various methods, including electroencephalography (EEG), (10) magnetic encephalography (MEG), (11) and positron emission tomography (PET), to investigate functional connectivity. (12) One modality recently used to determine functional connectivity is functional nearinfrared spectroscopy (fNIRS). ( 13) fNIRS is an optical technique that uses near-infrared spectroscopy to monitor the brain.…”