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Potential for high‐permittivity materials to reduce local SAR at a pacemaker lead tip during MRI of the head with a body transmit coil at 3 T
Author(s) -
Yu Zidan,
Xin Xuegang,
Collins Christopher M.
Publication year - 2017
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.26344
Subject(s) - permittivity , electromagnetic coil , specific absorption rate , magnetic resonance imaging , materials science , relative permittivity , head (geology) , lead (geology) , nuclear magnetic resonance , human head , absorption (acoustics) , shell (structure) , electric field , biomedical engineering , physics , computer science , dielectric , composite material , medicine , optoelectronics , radiology , geology , telecommunications , quantum mechanics , geomorphology , antenna (radio)
Purpose To illustrate the potential for high permittivity materials to be used in decreasing peak local SAR associated with implants when the imaging region is far from the implant. Methods We performed numerical simulations of a human subject with a pacemaker in a body‐sized birdcage coil driven at 128 MHz with and without a thin (5 mm) shell of material of high electric permittivity around the head. Results For a shell with relative permittivity of 600, the maximum specific energy absorption rate averaged over any 1 g of tissue near the pacemaker was reduced by 73.5% for a given B 1 field strength at the center of the brain. Conclusion Although further study is required, initial simulations indicate that strategic use of high permittivity materials may broaden the conditions under which patients with certain implants can be imaged safely. Magn Reson Med 78:383–386, 2017. © 2016 International Society for Magnetic Resonance in Medicine