title: Impaired cerebral blood flow networks in temporal lobe epilepsy with hippocampal sclerosis: A graph theoretical approach.
abstract: Graph theory is an emerging method to investigate brain networks. Altered cerebral blood flow (CBF) has frequently been reported in temporal lobe epilepsy (TLE), but graph theoretical findings of CBF are poorly understood. Here, we explored graph theoretical networks of CBF in TLE using arterial spin labeling imaging. We recruited patients with TLE and unilateral hippocampal sclerosis (HS) (19 patients with left TLE, and 21 with right TLE) and 20 gender- and age-matched healthy control subjects. We obtained all participants' CBF maps using pseudo-continuous arterial spin labeling and analyzed them using the Graph Analysis Toolbox (GAT) software program. As a result, compared to the controls, the patients with left TLE showed a significantly low clustering coefficient (p=0.024), local efficiency (p=0.001), global efficiency (p=0.010), and high transitivity (p=0.015), whereas the patients with right TLE showed significantly high assortativity (p=0.046) and transitivity (p=0.011). The group with right TLE also had high characteristic path length values (p=0.085), low global efficiency (p=0.078), and low resilience to targeted attack (p=0.101) at a trend level. Lower normalized clustering coefficient (p=0.081) in the left TLE and higher normalized characteristic path length (p=0.089) in the right TLE were found also at a trend level. Both the patients with left and right TLE showed significantly decreased clustering in similar areas, i.e., the cingulate gyri, precuneus, and occipital lobe. Our findings revealed differing left-right network metrics in which an inefficient CBF network in left TLE and vulnerability to irritation in right TLE are suggested. The left-right common finding of regional decreased clustering might reflect impaired default-mode networks in TLE.
authors: Department of Radiology, National Center of Neurology and Psychiatry, Tokyo, Japan; Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors: Daichi
authors: D
authors: Sone
authors: Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors: Hiroshi
authors: H
authors: Matsuda
authors: Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors: Miho
authors: M
authors: Ota
authors: Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors: Norihide
authors: N
authors: Maikusa
authors: Department of Radiology, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors: Yukio
authors: Y
authors: Kimura
authors: Department of Radiology, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors: Kaoru
authors: K
authors: Sumida
authors: Department of Radiology, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors: Kota
authors: K
authors: Yokoyama
authors: Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors: Etsuko
authors: E
authors: Imabayashi
authors: Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors: Masako
authors: M
authors: Watanabe
authors: Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors: Yutaka
authors: Y
authors: Watanabe
authors: Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors: Mitsutoshi
authors: M
authors: Okazaki
authors: Department of Radiology, National Center of Neurology and Psychiatry, Tokyo, Japan. Electronic address: snoriko@ncnp.go.jp.
authors: Noriko
authors: N
authors: Sato
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004833:Epilepsy, Temporal Lobe / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006624:Hippocampus / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012598:Sclerosis / Q000473:pathology / Q000503:physiopathology; D012984:Software; D013702:Temporal Lobe / Q000473:pathology* / Q000503:physiopathology
keywords: Arterial spin labeling; Brain network; Cerebral blood flow; Graph theory; Temporal lobe epilepsy