Document Detail

Simulated MR magnetic field induces steady-state changes in brain dynamics: Implications for interpretation of functional MR studies.
MedLine Citation:
PMID:  20665778     Owner:  NLM     Status:  MEDLINE    
We examined whether a magnetic field comparable to one of the fields produced during MRI induced steady-state changes in brain electrical activity while the field was applied (called a presence effect to distinguish it from evoked potentials). The electroencephalogram was measured from standard scalp locations in the presence and absence of 100-200 microT, 60 Hz, and the effect of the field was evaluated by nonlinear (recurrence analysis) and linear techniques; individual subjects served as their own controls. Using recurrence analysis, changes in brain activity lasting 1 sec (the longest interval considered) were found in 21 of 22 subjects (P < 0.05 for each subject). The presence effect was not detected using linear analysis and was reversible, as indicated by a return of brain activity to baseline levels in all subjects within 2 sec of field offset. The possible role of artifacts or systematic errors was ruled out by studies using electrical phantoms and by analyses of electroencephalograms recorded during sham exposure. It is reasonable to expect that actual scanner magnetic fields also produce nonlinear steady-state perturbations of brain dynamical activity. The effect may influence the picture of brain connectivity inferred in some functional MR studies.
Andrew A Marino; Simona Carrubba; Clifton Frilot; Andrew L Chesson; Eduardo Gonzalez-Toledo
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine     Volume:  64     ISSN:  1522-2594     ISO Abbreviation:  Magn Reson Med     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-07-28     Completed Date:  2011-01-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8505245     Medline TA:  Magn Reson Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  349-57     Citation Subset:  IM    
Department of Orthopaedic Surgery, LSU Health Sciences Center, Shreveport, Louisiana, USA.
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MeSH Terms
Brain / physiology*,  radiation effects*
Dose-Response Relationship, Radiation
Electric Stimulation / methods*
Evoked Potentials / physiology*,  radiation effects*
Magnetic Resonance Imaging / methods*
Radiation Dosage
Young Adult

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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