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Article: Computation of electromagnetic fields for high-frequency magnetic resonance imaging applications

TitleComputation of electromagnetic fields for high-frequency magnetic resonance imaging applications
Authors
Issue Date1996
PublisherInstitute of Physics Publishing. The Journal's web site is located at http://www.iop.org/journals/pmb
Citation
Physics In Medicine And Biology, 1996, v. 41 n. 12, p. 2719-2738 How to Cite?
AbstractA numerical method is presented to compute electromagnetic fields inside a 2 mm high resolution, anatomically detailed model of a human head for high-frequency magnetic resonance imaging (MRI) applications. The method uses the biconjugate gradient algorithm in combination with the fast Fourier transform to solve a matrix equation resulting from the discretization of an integrodifferential equation representing the original physical problem. Given the current distribution in an MRI coil, the method can compute both the electric field (thus the specific energy absorption rate (SAR)) and the magnetic field, also known as the B1 field. Results for the SAR and B1 field distribution, excited by a linear and a quadrature birdcage coil, are calculated and presented at 64 MHz, 128 MHz and 256 MHz, corresponding to the operating frequencies of the 1.5 T, 3 T and 6 T MRI systems. It is shown that compared with that at 64 MHz, the SAR at 128 MHz is increased by a factor over 5 and the SAR at 256 MHz is increased by a factor over 10, assuming the same current strength in the coil. Furthermore, compared with the linear excitation, the average SAR for the quadrature excitation is reduced by a factor over 2 and the maximum SAR is reduced by a factor over 3. It is also shown that the B1 field at high frequencies exhibits a strong inhomogeneity, which is attributed to dielectric resonance.
Persistent Identifierhttp://hdl.handle.net/10722/182565
ISSN
2015 Impact Factor: 2.811
2015 SCImago Journal Rankings: 1.577
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorJin, JMen_US
dc.contributor.authorChen, Jen_US
dc.contributor.authorChew, WCen_US
dc.contributor.authorGan, Hen_US
dc.contributor.authorMagin, RLen_US
dc.contributor.authorDimbylow, PJen_US
dc.date.accessioned2013-05-02T05:15:53Z-
dc.date.available2013-05-02T05:15:53Z-
dc.date.issued1996en_US
dc.identifier.citationPhysics In Medicine And Biology, 1996, v. 41 n. 12, p. 2719-2738en_US
dc.identifier.issn0031-9155en_US
dc.identifier.urihttp://hdl.handle.net/10722/182565-
dc.description.abstractA numerical method is presented to compute electromagnetic fields inside a 2 mm high resolution, anatomically detailed model of a human head for high-frequency magnetic resonance imaging (MRI) applications. The method uses the biconjugate gradient algorithm in combination with the fast Fourier transform to solve a matrix equation resulting from the discretization of an integrodifferential equation representing the original physical problem. Given the current distribution in an MRI coil, the method can compute both the electric field (thus the specific energy absorption rate (SAR)) and the magnetic field, also known as the B1 field. Results for the SAR and B1 field distribution, excited by a linear and a quadrature birdcage coil, are calculated and presented at 64 MHz, 128 MHz and 256 MHz, corresponding to the operating frequencies of the 1.5 T, 3 T and 6 T MRI systems. It is shown that compared with that at 64 MHz, the SAR at 128 MHz is increased by a factor over 5 and the SAR at 256 MHz is increased by a factor over 10, assuming the same current strength in the coil. Furthermore, compared with the linear excitation, the average SAR for the quadrature excitation is reduced by a factor over 2 and the maximum SAR is reduced by a factor over 3. It is also shown that the B1 field at high frequencies exhibits a strong inhomogeneity, which is attributed to dielectric resonance.en_US
dc.languageengen_US
dc.publisherInstitute of Physics Publishing. The Journal's web site is located at http://www.iop.org/journals/pmben_US
dc.relation.ispartofPhysics in Medicine and Biologyen_US
dc.subject.meshAlgorithmsen_US
dc.subject.meshElectromagnetic Fieldsen_US
dc.subject.meshFourier Analysisen_US
dc.subject.meshHeaden_US
dc.subject.meshHumansen_US
dc.subject.meshMagnetic Resonance Imagingen_US
dc.subject.meshModels, Theoreticalen_US
dc.subject.meshPhantoms, Imagingen_US
dc.titleComputation of electromagnetic fields for high-frequency magnetic resonance imaging applicationsen_US
dc.typeArticleen_US
dc.identifier.emailChew, WC: wcchew@hku.hken_US
dc.identifier.authorityChew, WC=rp00656en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1088/0031-9155/41/12/011en_US
dc.identifier.pmid8971965-
dc.identifier.scopuseid_2-s2.0-0029827185en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0029827185&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume41en_US
dc.identifier.issue12en_US
dc.identifier.spage2719en_US
dc.identifier.epage2738en_US
dc.identifier.isiWOS:A1996VY19100011-
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridJin, JM=7403588231en_US
dc.identifier.scopusauthoridChen, J=8947455300en_US
dc.identifier.scopusauthoridChew, WC=36014436300en_US
dc.identifier.scopusauthoridGan, H=36807480800en_US
dc.identifier.scopusauthoridMagin, RL=7005342618en_US
dc.identifier.scopusauthoridDimbylow, PJ=7003510973en_US

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