Connectivity in ictal single photon emission computed tomography perfusion: a cortico-cortical evoked potential study
| Autor: | Chetan S. Nayak, Wim Van Paesschen, Zhong I. Wang, Richard M. Leahy, John C. Mosher, Juan Bulacio, Simon Tousseyn, Jorge Gonzalez-Martinez, Guiyun Wu, Imad Najm, Balu Krishnan, Andreas V. Alexopoulos, Sattawut Wongwiangjunt, Dileep Nair |
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| Rok vydání: | 2017 |
| Předmět: |
Adult
Male 0301 basic medicine Drug Resistant Epilepsy Adolescent Stimulation Electroencephalography Single-photon emission computed tomography Young Adult 03 medical and health sciences Epilepsy 0302 clinical medicine Humans Medicine Ictal Evoked potential Child Evoked Potentials Aged Cerebral Cortex Tomography Emission-Computed Single-Photon medicine.diagnostic_test business.industry Functional Neuroimaging Original Articles Middle Aged medicine.disease Electric Stimulation nervous system diseases Evoked potential study 030104 developmental biology nervous system Female Neurology (clinical) business Perfusion Neuroscience 030217 neurology & neurosurgery |
| Zdroj: | Brain. 140:1872-1884 |
| ISSN: | 1460-2156 0006-8950 |
| DOI: | 10.1093/brain/awx123 |
| Popis: | Subtraction ictal and interictal single photon emission computed tomography can demonstrate complex ictal perfusion patterns. Regions with ictal hyperperfusion are suggested to reflect seizure onset and propagation pathways. The significance of ictal hypoperfusion is not well understood. The aim of this study was to verify whether ictal perfusion changes, both hyper- and hypoperfusion, correspond to electrically connected brain networks. A total of 36 subtraction ictal and interictal perfusion studies were analysed in 31 consecutive medically refractory focal epilepsy patients, evaluated by stereo-electroencephalography that demonstrated a single focal onset. Cortico-cortical evoked potential studies were performed after repetitive electrical stimulation of the ictal onset zone. Evoked responses at electrode contacts outside the stimulation site were used as a measure of connectivity. The evoked responses at these electrodes were compared to ictal perfusion values noted at these locations. In 67% of studies, evoked responses were significantly larger in hyperperfused compared to baseline-perfused areas. The majority of hyperperfused contacts also had significantly increased evoked responses relative to pre-stimulus electroencephalogram. In contrast, baseline-perfused and hypoperfused contacts mainly demonstrated non-significant evoked responses. Finally, positive significant correlations (P < 0.05) were found between perfusion scores and evoked responses in 61% of studies. When the stimulated ictal onset area was hyperperfused, 82% of studies demonstrated positive significant correlations. Following stimulation of hyperperfused areas outside seizure onset, positive significant correlations between perfusion changes and evoked responses could be seen, suggesting bidirectional connectivity. We conclude that strong connectivity was demonstrated between the ictal onset zone and hyperperfused regions, while connectivity was weaker in the direction of baseline-perfused or hypoperfused areas. In trying to understand a patient’s epilepsy, one should consider the contribution of all hyperperfused regions, as these are likely not random, but represent an electrically connected epileptic network. |
| Databáze: | OpenAIRE |
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