Kiyohide Usami1, Riki Matsumoto2, Nobukatsu Sawamoto3, Hiroatsu Murakami4, Morito Inouchi5, Tomoyuki Fumuro6, Akihiro Shimotake1, Takeo Kato7, Tatsuya Mima8, Hiroshi Shirozu4, Hiroshi Masuda4, Hidenao Fukuyama8, Ryosuke Takahashi1, Shigeki Kameyama4, Akio Ikeda9. 1. Department of Neurology, Kyoto University, Graduate School of Medicine, Kyoto, Japan. 2. Department of Epilepsy, Movement Disorders and Physiology, Kyoto University, Graduate School of Medicine, Kyoto, Japan. Electronic address: matsumot@kuhp.kyoto-u.ac.jp. 3. Department of Neurology, Kyoto University, Graduate School of Medicine, Kyoto, Japan; Human Brain Research Center, Kyoto University, Graduate School of Medicine, Kyoto, Japan. 4. Department of Neurosurgery, Nishi-Niigata Chuo National Hospital, Niigata, Japan. 5. Department of Neurology, Kyoto University, Graduate School of Medicine, Kyoto, Japan; Department of Respiratory Medicine, Kyoto University, Graduate School of Medicine, Kyoto, Japan. 6. Research and Educational Unit of Leaders for Integrated Medical System, Kyoto University, Kyoto, Japan. 7. Department of Pediatrics, Kyoto University, Graduate School of Medicine, Kyoto, Japan. 8. Human Brain Research Center, Kyoto University, Graduate School of Medicine, Kyoto, Japan. 9. Department of Epilepsy, Movement Disorders and Physiology, Kyoto University, Graduate School of Medicine, Kyoto, Japan. Electronic address: akio@kuhp.kyoto-u.ac.jp.
Abstract
OBJECTIVE: To investigate the brain networks involved in epileptogenesis/encephalopathy associated with hypothalamic hamartoma (HH) by EEG with functional MRI (EEG-fMRI), and evaluate its efficacy in locating the HH interface in comparison with subtraction ictal SPECT coregistered to MRI (SISCOM). METHODS: Eight HH patients underwent EEG-fMRI. All had gelastic seizures (GS) and 7 developed other seizure types. Using a general linear model, spike-related activation/deactivation was analyzed individually by applying a hemodynamic response function before, at, and after spike onset (time-shift model=-8-+4s). Group analysis was also performed. The sensitivity of EEG-fMRI in identifying the HH interface was compared with SISCOM in HH patients having unilateral hypothalamic attachment. RESULTS: EEG-fMRI revealed activation and/or deactivation in subcortical structures and neocortices in all patients. 6/8 patients showed activation in or around the hypothalamus with the HH interface with time-shift model before spike onset. Group analysis showed common activation in the ipsilateral hypothalamus, brainstem tegmentum, and contralateral cerebellum. Deactivation occurred in the default mode network (DMN) and bilateral hippocampi. Among 5 patients with unilateral hypothalamic attachment, activation in or around the ipsilateral hypothalamus was seen in 3 using EEG-fMRI, whereas hyperperfusion was seen in 1 by SISCOM. SIGNIFICANCE: Group analysis of this preliminary study may suggest that the commonly activated subcortical network is related to generation of GS and that frequent spikes lead to deactivation of the DMN and hippocampi, and eventually to a form of epileptic encephalopathy. Inter-individual variance in neocortex activation explains various seizure types among patients. EEG-fMRI enhances sensitivity in detecting the HH interface compared with SISCOM.
OBJECTIVE: To investigate the brain networks involved in epileptogenesis/encephalopathy associated with hypothalamic hamartoma (HH) by EEG with functional MRI (EEG-fMRI), and evaluate its efficacy in locating the HH interface in comparison with subtraction ictal SPECT coregistered to MRI (SISCOM). METHODS: Eight HH patients underwent EEG-fMRI. All had gelastic seizures (GS) and 7 developed other seizure types. Using a general linear model, spike-related activation/deactivation was analyzed individually by applying a hemodynamic response function before, at, and after spike onset (time-shift model=-8-+4s). Group analysis was also performed. The sensitivity of EEG-fMRI in identifying the HH interface was compared with SISCOM in HH patients having unilateral hypothalamic attachment. RESULTS: EEG-fMRI revealed activation and/or deactivation in subcortical structures and neocortices in all patients. 6/8 patients showed activation in or around the hypothalamus with the HH interface with time-shift model before spike onset. Group analysis showed common activation in the ipsilateral hypothalamus, brainstem tegmentum, and contralateral cerebellum. Deactivation occurred in the default mode network (DMN) and bilateral hippocampi. Among 5 patients with unilateral hypothalamic attachment, activation in or around the ipsilateral hypothalamus was seen in 3 using EEG-fMRI, whereas hyperperfusion was seen in 1 by SISCOM. SIGNIFICANCE: Group analysis of this preliminary study may suggest that the commonly activated subcortical network is related to generation of GS and that frequent spikes lead to deactivation of the DMN and hippocampi, and eventually to a form of epilepticencephalopathy. Inter-individual variance in neocortex activation explains various seizure types among patients. EEG-fMRI enhances sensitivity in detecting the HH interface compared with SISCOM.
Authors: Y Maki; J Natsume; Y Ito; Y Okai; E Bagarinao; H Yamamoto; S Ogaya; T Takeuchi; T Fukasawa; F Sawamura; T Mitsumatsu; S Maesawa; R Saito; Y Takahashi; H Kidokoro Journal: AJNR Am J Neuroradiol Date: 2022-09-22 Impact factor: 4.966