Análise da origem das ondas trifásicas utilizando a neuroimagem quantitativa
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Data
2018-07-14
Autores
Meira, Alex Tiburtino
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Universidade Estadual Paulista (Unesp)
Resumo
O padrão eletroencefalográfico mais comum em pacientes críticos é o distúrbio da atividade de base. Ondas trifásicas (OTs) constituem um padrão periódico classicamente relacionado às encefalopatias metabólicas. A maioria dos pacientes com OTs tem alteração do nível de consciência, e acredita-se que este padrão represente disfunção tálamo-cortical. Entretanto, o significado exato e o mecanismo das OTs permanecem desconhecidos. O objetivo principal deste estudo foi avaliar a origem das OTs utilizando o eletroencefalograma quantitativo (EEGq) e a tomografia computadorizada de crânio (TCC). 28 pacientes foram investigados. A análise dos focos das OTs foi realizada nas descargas promediadas para cada um dos indivíduos. Os mapas dos focos foram extraídos desta avaliação. As TCs foram submetidas à normalização e segmentação automática da substância cinzenta. Finalmente, uma análise de correlação voxel-a-voxel de todo o grupo foi realizada entre os mapas dos focos das OTs e as imagens da substância cinzenta. A análise do foco mostrou envolvimento principalmente do cíngulo anterior. A análise de correlação revelou áreas de correlação moderada positiva (giro do cíngulo posterior; r = 0,5) e negativa (caudado; r = -0,51) entre os métodos.
The most frequent electroencephalographic pattern in critically ill patients is diffuse background slowing. Triphasic waves (TW) is a periodic pattern classically described in metabolic encephalopathic patients. Most patients with TW have altered level of consciousness, and this pattern is believed to represent thalamus-cortical dysfunction. However, the exact meaning and mechanism of TWs remains unknown. The main objective of this study was to evaluate the source of TWs using quantitative electroencephalogram (qEEG) and tomography (CT). 28 patients were investigated. Source analysis was performed in the averaged TWs for each individual. Source maps were extracted from this evaluation. CTs were submitted to normalization and automatic segmentation of gray matter. Finally, voxel-wise correlation analysis for the whole group was conducted between qEEG source maps and gray matter images. Source analysis showed involvement mainly of the anterior cingulate cortex. Correlation analysis disclosed moderate positive (posterior cingulate; r = 0.5) and negative (caudate; r = -0.51) correlations between the methods.
The most frequent electroencephalographic pattern in critically ill patients is diffuse background slowing. Triphasic waves (TW) is a periodic pattern classically described in metabolic encephalopathic patients. Most patients with TW have altered level of consciousness, and this pattern is believed to represent thalamus-cortical dysfunction. However, the exact meaning and mechanism of TWs remains unknown. The main objective of this study was to evaluate the source of TWs using quantitative electroencephalogram (qEEG) and tomography (CT). 28 patients were investigated. Source analysis was performed in the averaged TWs for each individual. Source maps were extracted from this evaluation. CTs were submitted to normalization and automatic segmentation of gray matter. Finally, voxel-wise correlation analysis for the whole group was conducted between qEEG source maps and gray matter images. Source analysis showed involvement mainly of the anterior cingulate cortex. Correlation analysis disclosed moderate positive (posterior cingulate; r = 0.5) and negative (caudate; r = -0.51) correlations between the methods.
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Palavras-chave
Ondas trifásicas, Encefalopatia, Eletroencefalografia, Triphasic waves, Encefalopathy, Electroencephalography