Moving GLM ballistocardiogram artifact reduction for EEG acquired simultaneously with fMRI.
Clin Neurophysiol
; 118(5): 981-98, 2007 May.
Article
em En
| MEDLINE
| ID: mdl-17368972
ABSTRACT
OBJECTIVE:
Simultaneous acquisition of electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) enables studies of brain activity at both high temporal and high spatial resolution. However, EEG acquired in a magnetic field is contaminated by ballistocardiogram (BKG) artifact. The most commonly used method of BKG artifact reduction, averaged artifact subtraction (AAS), was not designed to account for overlapping BKG waveforms generated by adjacent beats. We describe a new method based on a moving general linear model (mGLM) that accounts for overlapping BKG waveforms.METHODS:
Simultaneous EEG-fMRI at 3 Tesla was performed in nine normal human subjects (8-11 runs/subject, 5.52 min/run). Gradient switching artifact was effectively reduced using commercially supplied procedures. Cardiac beats were detected using a novel correlation detector algorithm applied to the EKG trace. BKG artifact was reduced using both mGLM and AAS.RESULTS:
mGLM recovered BKG waveforms outlasting the median inter-beat interval. mGLM more effectively than AAS removed variance in the EEG attributable to BKG artifact.CONCLUSIONS:
mGLM offers advantages over AAS especially in the presence of variable heart rate.SIGNIFICANCE:
The BKG artifact reduction procedure described herein improves the technique of simultaneous EEG-fMRI. Potential applications include basic investigations of the relationship between scalp potentials and functional imaging signals as well as clinical localization of epileptic foci.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Balistocardiografia
/
Imageamento por Ressonância Magnética
/
Artefatos
/
Eletroencefalografia
Tipo de estudo:
Prognostic_studies
/
Risk_factors_studies
Limite:
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
Clin Neurophysiol
Assunto da revista:
NEUROLOGIA
/
PSICOFISIOLOGIA
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Estados Unidos