Heating Near Implanted Medical Devices by the MRI RF-magnetic Field

Nyenhuis, J.A.; Kildishev, Alexander V.; Bourland, J. D.; Foster, Kenneth A.; Graber, G. P.; Athey, T. Whit

doi:10.1109/intmag.1999.837338

Cited by 22 publications

(44 citation statements)

References 1 publication

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“…RF and pulsed gradient magnetic fields used for MRI induce currents in the body (4,5,8,53,(61)(62)(63)68,69). It is well known that implants that have electronically activated or electrically conductive components can locally increase these currents, and under certain operational conditions, excessive heating of biomedical devices may occur in association with MR procedures (4,5,8,53,(61)(62)(63)68,69).…”

Section: Mr Safe Fiber-optic Cardiac Pacing Leadmentioning

confidence: 99%

“…It is well known that implants that have electronically activated or electrically conductive components can locally increase these currents, and under certain operational conditions, excessive heating of biomedical devices may occur in association with MR procedures (4,5,8,53,(61)(62)(63)68,69). For example, exorbitant temperature elevations from MRI-related heating have been reported for cardiac pacemakers, neurostimulation systems indwelling catheters with metallic components (e.g., thermodilution catheters), guide wires, disconnected or broken-surface RF coils, and improperly used physiologic monitors resulting in first-, second-, or third-degree burns (3)(4)(5)8,59,68,75).…”

Section: Mr Safe Fiber-optic Cardiac Pacing Leadmentioning

confidence: 99%

“…While excessive heating and the induction of electrical currents may also present risks to patients with implants or devices, these MR safety problems are typically associated with implants that have elongated configurations and/or that are electronically activated (e.g., neurostimulation systems, cardiac pacemakers, etc.) (1)(2)(3)(4)(5)28,53,61,62,68,75).…”

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confidence: 99%

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Magnetic resonance safety update 2002: Implants and devices

Shellock

2002

Magnetic Resonance Imaging

249

279

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The preservation of a safe magnetic resonance (MR) environment requires constant vigilance by MR healthcare professionals, particularly with regard to the management of patients with metallic biomedical implants or devices. The variety and complexity of implants and devices constantly changes, requiring continuous attention and diligence with regard to obtaining the most current and accurate information about these objects relative to the MR environment. This review article discusses MR safety and MR compatibility issues and presents important information for a variety of implants and devices, with an emphasis on those objects that have recently undergone evaluation or that require additional consideration because of existing controversy or confusion.

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Section: Mr Safe Fiber-optic Cardiac Pacing Leadmentioning

confidence: 99%

Section: Mr Safe Fiber-optic Cardiac Pacing Leadmentioning

confidence: 99%

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Magnetic resonance safety update 2002: Implants and devices

Shellock

2002

Magnetic Resonance Imaging

249

279

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“…Recently, there have been investigations of heating near implanted medical devices exposed to MR imaging (11,12). For the present calculation, a realistic human model was implanted with several metallic implants individually and then exposed to the RF magnetic field in the MR birdcage body coil.…”

Section: Sar Distributions In Realistic Human Model With Metallic Impmentioning

confidence: 99%

Safety of metallic implants in magnetic resonance imaging

2001

Magnetic Resonance Imaging

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Magnetic resonance (MR) imaging has become a commonly accepted medical procedure. Manufacturers of medical implant devices are submitting claims that their devices are safe and effective in a MR environment. This paper concentrates on the issue of heating of patients due to the interaction of metallic implants with the strong radiofrequency (RF) magnetic field produced by the MR scanner. The commercially available program XFDTD was used to calculate the specific absorption rate (SAR) distribution in a realistic model of the human body. The body contained a metallic implant and was exposed to RF magnetic fields at 64 MHz from a model of a MR birdcage body coil. The results of the calculation showed that the magnitude of the increased heating of tissues due to the presence of the metallic implant depended on the dimensions, orientation, shape, and location of the metallic implant in the patient. This increased heating of surrounding tissues primarily concentrates in a small volume near the tip of the metallic wire. When the whole-body SAR was normalized to 1 W/kg, a calculated value of 41 W/kg was obtained at this location if the absorption was averaged over 1 g of tissue. However, a maximum value of 310 W/kg was calculated when the absorption was averaged over 1/8 g of tissue.

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“…[3][4][5][6][7][8][9][10][11] However, burn accidents caused by MR procedures have been reported. [12][13][14] The mechanism of RF irradiation-induced heating of human body implants is complicated and in‰uenced by quality of material and shape of the implant, body weight and height, electrical properties of various internal organs, thermoregulatory reaction, blood ‰ow, and other parameters.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of RF Heating due to Various Implants during MR Procedures

et al. 2011

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We evaluated radiofrequency (RF) heating of various implants embedded in a gel phantom during magnetic resonance (MR) procedures. We examined the dependence of RF heating on variation in speciˆc absorption rate (SAR) and angle between the implant and the static magneticˆeld (B 0 ) and on the displacement of the phantom in the irradiation coil using a 1.5-tesla MR system, and we compared the in‰uence of RF heating on the same implant using a 3.0T MR system.Our results support the occurrence of RF heating of implants made of non-magnetizing metal. We observed greater RF heating when the implant was set parallel to B 0 , embedded at a shallower depth, and placed at the center of the RF irradiation coil. We also conˆrmed that the rise in temperature was proportionate to the increase in SAR. We considered the diŠerence in temperature elevation on depth of embedding to re‰ect the skin-depth eŠect of RF intensity for both the 1.5-and 3.0-T MR systems.

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Heating Near Implanted Medical Devices by the MRI RF-magnetic Field

Cited by 22 publications

References 1 publication

Magnetic resonance safety update 2002: Implants and devices

Magnetic resonance safety update 2002: Implants and devices

Safety of metallic implants in magnetic resonance imaging

Evaluation of RF Heating due to Various Implants during MR Procedures

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