RF heating due to conductive wires during MRI depends on the phase distribution of the transmit field

Christopher J. Yeung, Robert C. Susil, Ergin Atalar

Research output: Contribution to journalArticle

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 "implantfriendly" coil design.

Original languageEnglish (US)
Pages (from-to)1096-1098
Number of pages3
JournalMagnetic Resonance in Medicine
Volume48
Issue number6
DOIs
StatePublished - Dec 1 2002

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Keywords

  • Guidewire
  • Interventional MRI
  • Metallic implants
  • Method of moments
  • RF heating
  • Safety

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

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