RF heating due to conductive wires during MRI depends on the phase distribution of the transmit field.
Magn Reson Med
; 48(6): 1096-8, 2002 Dec.
Article
em En
| MEDLINE
| ID: mdl-12465125
ABSTRACT
In many studies concerning wire heating during MR imaging, a "resonant wire length" that maximizes RF heating is determined. This may lead to the nonintuitive conclusion that adding more wire, so as to avoid this resonant length, will actually improve heating safety. Through a theoretical analysis using the method of moments, we show that this behavior depends on the phase distribution of the RF transmit field. If the RF transmit field has linear phase, with slope equal to the real part of the wavenumber in the tissue, long wires always heat more than short wires. In order to characterize the intrinsic safety of a device without reference to a specific body coil design, this maximum-tip heating phase distribution must be considered. Finally, adjusting the phase distribution of the electric field generated by an RF transmit coil may lead to an "implant-friendly" coil design.
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Base de dados:
MEDLINE
Assunto principal:
Imageamento por Ressonância Magnética
/
Temperatura Alta
Tipo de estudo:
Etiology_studies
/
Risk_factors_studies
Idioma:
En
Revista:
Magn Reson Med
Assunto da revista:
DIAGNOSTICO POR IMAGEM
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos