Calculation of electric fields induced near metal implants by magnetic resonance imaging switched-gradient magnetic fields

Buechler, Dale; Durney, Carl H.; Christensen, Douglas A.

doi:10.1016/s0730-725x(97)00179-3

Cited by 17 publications

(19 citation statements)

References 5 publications

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“…In addition to the effects of switching gradient fields discussed above, interaction with implanted devices containing metals must also be carefully considered . In pacemakers, gradient field switching could possibly induce currents that might create competitive pacing, with the potential of causing life‐threatening arrhythmias .…”

Section: The Gradient Fieldsmentioning

confidence: 99%

“…In addition to the effects of switching gradient fields discussed above, interaction with implanted devices containing metals must also be carefully considered. 114 In pacemakers, gradient field switching could possibly induce currents that might create competitive pacing, with the potential of causing life-threatening arrhythmias. [115][116][117] Unintended electrical stimulation of tissue due to induction of currents on the leads of other active implants such as neurological stimulators could be another concern.…”

Section: Rf Interaction With Metallic Objects Forming Loopsmentioning

confidence: 99%

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The physics of MRI safety

Panych

Madore

2017

Magnetic Resonance Imaging

140

150

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The main risks associated with magnetic resonance imaging (MRI) have been extensively reported and studied; for example, everyday objects may turn into projectiles, energy deposition can cause burns, varying fields can induce nerve stimulation, and loud noises can lead to auditory loss. The present review article is geared toward providing intuition about the physical mechanisms that give rise to these risks. On the one hand, excellent literature already exists on the practical aspect of risk management, with clinical workflow and recommendations. On the other hand, excellent technical articles also exist that explain these risks from basic principles of electromagnetism. We felt that an underserved niche might be found between the two, ie, somewhere between basic science and practical advice, to help develop intuition about electromagnetism that might prove of practical value when working around MR scanners. Following a wide‐ranging introduction, risks originating from the main magnetic field, the excitation RF electromagnetic field, and switching of the imaging gradients will be presented in turn. Level of Evidence: 5 Technical Efficacy: 1 J. Magn. Reson. Imaging 2018;47:28–43.

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Section: The Gradient Fieldsmentioning

confidence: 99%

Section: Rf Interaction With Metallic Objects Forming Loopsmentioning

confidence: 99%

The physics of MRI safety

Panych

Madore

2017

Magnetic Resonance Imaging

140

150

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“…Some of the studies investigated safety aspects, such as heating or deflection problems (1–4). For example, the existence of a high electric field that developed around a spinal fusion implant (a U‐shaped 11.8‐cm‐long wire implant) was calculated (5). Image artifact problems were reported on various metallic implants.…”

Section: Introductionmentioning

confidence: 99%

Gradient field switching as a source for artifacts in MR imaging of metallic stents

Shenhav

Azhari

2004

Magnetic Resonance in Med

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Metallic implants, such as stents, have long been a concern in magnetic resonance imaging (MRI). In addition to safety issues, they are commonly associated with image artifacts. The mechanisms of radiofrequency-(RF) and susceptibility-induced artifacts have been thoroughly investigated. However, gradientswitching-induced artifacts have not been analyzed. In this study it was demonstrated that gradient switching may be a source of artifacts in metallic stent MR imaging. These artifacts differ from those caused by the RF pulse. A theoretical explanation is provided as well.

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“…It is not known whether these two quantities are involved in any possible therapeutic bene®t, but it is important to understand their magnitudes and patterns in assessing a variety of possible mechanisms. These calculations were made by applying our 3 dimensional (3D) ®nite difference frequency domain technique for solving Maxwell's equations [Buechler, 1997;Buechler et al, 1997] to a knee section from a highly accurate human body model [Gandhi, 1995].…”

Section: Introductionmentioning

confidence: 99%

Calculation of electric fields induced in the human knee by a coil applicator

Buechler

Christensen

Durney

et al. 2001

Bioelectromagnetics

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Calculations are presented of the induced electric fields and current densities in the cartilage of the knee produced by a coil applicator developed for applying pulsed magnetic fields to osteoarthritic knees. This applicator produces a sawtooth-like magnetic field waveform composed of a series of 260-micros pulses with a peak to peak magnitude of approximately 0.12 mT in the cartilage region. The simulations were performed using a recently developed 3 dimensional finite difference frequency domain technique for solving Maxwell's equations with an equivalent circuit model. The tissue model was obtained from the anatomically segmented human body model of Gandhi. The temporal peak electric field magnitude was found to be -153 mV/m, averaged within the medial cartilage of the knee for the typical dB/dt excitation levels of this coil. The technique can be extended to analyze other excitation waveforms and applicator designs.

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Calculation of electric fields induced near metal implants by magnetic resonance imaging switched-gradient magnetic fields

Cited by 17 publications

References 5 publications

The physics of MRI safety

The physics of MRI safety

Gradient field switching as a source for artifacts in MR imaging of metallic stents

Calculation of electric fields induced in the human knee by a coil applicator

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