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Spatial distribution of RF‐induced E‐fields and implant heating in MRI
Author(s) -
Nordbeck Peter,
Fidler Florian,
Weiss Ingo,
Warmuth Marcus,
Friedrich Michael T.,
Ehses Philipp,
Geistert Wolfgang,
Ritter Oliver,
Jakob Peter M.,
Ladd Mark E.,
Quick Harald H.,
Bauer Wolfgang R.
Publication year - 2008
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.21475
Subject(s) - imaging phantom , torso , implant , materials science , biomedical engineering , head (geology) , distribution (mathematics) , field (mathematics) , nuclear magnetic resonance , physics , optics , medicine , mathematics , surgery , anatomy , geomorphology , geology , mathematical analysis , pure mathematics
The purpose of this study was to assess the distribution of RF‐induced E‐fields inside a gel‐filled phantom of the human head and torso and compare the results with the RF‐induced temperature rise at the tip of a straight conductive implant, specifically examining the dependence of the temperature rise on the position of the implant inside the gel. MRI experiments were performed in two different 1.5T MR systems of the same manufacturer. E‐field distribution inside the liquid was assessed using a custom measurement system. The temperature rise at the implant tip was measured in various implant positions and orientations using fluoroptic thermometry. The results show that local E‐field strength in the direction of the implant is a critical factor in RF‐related tissue heating. The actual E‐field distribution, which is dependent on phantom/body properties and the MR‐system employed, must be considered when assessing the effects of RF power deposition in implant safety investigations. Magn Reson Med 60:312–319, 2008. © 2008 Wiley‐Liss, Inc.