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Induced magnetic force in human heads exposed to 4 T MRI
Author(s) -
Wang Ruiliang,
Wang GeneJack,
Goldstein Rita Z.,
Caparelli Elisabeth C.,
Volkow Nora D.,
Fowler Joanna S.,
Tomasi Dardo
Publication year - 2010
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22125
Subject(s) - midbrain , magnetic resonance imaging , pons , gyrus , brainstem , functional magnetic resonance imaging , anatomy , physics , medicine , nuclear magnetic resonance , radiology , central nervous system
Purpose: To map the distribution of the magnetic force induced in the human head during magnetic resonance imaging (MRI) at 4 T for a large group of healthy volunteers. Materials and Methods: The magnetic field distribution in the head of 100 men and 18 women was mapped using phase mapping techniques. Statistical parametric mapping methods using a family‐wise error (FWE) corrected threshold P < 0.05 and region‐of‐interest analyses were used to assess the significance of the results. Results: Eyeballs, orbitofrontal and temporal cortices, subcallosal gyrus, anterior cingulate, midbrain, and brainstem (pons) are the brain regions most susceptible to magnetic force. The strength of the magnetic force density in the head was lower than 11.5 ± 5.3 N/m 3 (right eyeball). The strength of the magnetic force density induced in occipital cortex varied linearly with the x‐rotation (pitch) angle. Conclusion: We found that the induced magnetic force is highly significant in the eyeballs, orbitofrontal and temporal cortices, subcallosal gyrus, anterior cingulate as well as midbrain and brainstem (pons), regardless of subjects' age or gender. The maximum induced magnetic force was 6 × 10 5 times weaker than the gravitational force; thus, biological effects of the magnetic force during imaging are not expected to be significant. J. Magn. Reson. Imaging 2010;31:815–820. ©2010 Wiley‐Liss, Inc.