Review of Patient Safety in Time-Varying Gradient Fields

Schaefer, Daniel J.; Bourland, J. D.; Nyenhuis, J.A.

doi:10.1002/1522-2586(200007)12:1<20::aid-jmri3>3.0.co;2-y

Cited by 216 publications

(188 citation statements)

References 27 publications

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“…Assuming constant values of E r and c , the minimum threshold is expected to occur at the position of maximum ␤(r), which we define as ␤ max . Equation [1] describes a linear relationship between the stimulation threshold and the gradient switching time. It is useful to simplify Eq.…”

Section: Theorymentioning

confidence: 99%

“…[1]. SR min is the minimum slew rate that must be applied to cause stimulation in the limit of infinitely long rise times.…”

Section: Theorymentioning

confidence: 99%

“…Gradient coil magnetostimulation has been studied for the past decade with emphasis on determining the dependence of thresholds on pulse sequence variables (1,2). There has been far less work investigating the effect of gradient coil design on magnetostimulation thresholds.…”

mentioning

confidence: 99%

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A comparison between human magnetostimulation thresholds in whole‐body and head/neck gradient coils

Chronik

Rutt

2001

Magnetic Resonance in Med

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Gradient coil magnetostimulation thresholds were measured in a group of 20 volunteers in both a whole-body gradient coil and a head/neck gradient coil. Both coils were operated using both x and y axes simultaneously (xy oblique mode). The waveform applied was a 64-lobe trapezoidal train with 1-ms flat-tops and varying rise times. Thresholds were based on the subjects' perception of stimulation, and painful sensations were not elic- The mean threshold curves were combined with the gradient system performance curves to produce operational limit curves. The operational limit curves for the head/neck coil system were verified to be higher than those of the whole-body coil; however, the head/neck system was also found to be physiologically limited over a greater range of its operation than was the body coil. Subject thresholds between the two coils were not well correlated. Magn Reson Med 46: 386 -394, 2001.

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Section: Theorymentioning

confidence: 99%

“…[1]. SR min is the minimum slew rate that must be applied to cause stimulation in the limit of infinitely long rise times.…”

Section: Theorymentioning

confidence: 99%

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A comparison between human magnetostimulation thresholds in whole‐body and head/neck gradient coils

Chronik

Rutt

2001

Magnetic Resonance in Med

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“…Ultrafast gradients are also essential in functional (echo-planar) MRI. Fast switching of high-amplitude gradients may, however, also increase the risk of peripheral nerve stimulations [6]. A high degree of gradient linearity over a large volume is required by the gradient system to keep image distortion in and around the image volume to a minimum.…”

Section: Main Magnet-homogeneous Static Magnetic Fieldmentioning

confidence: 99%

Magnetic resonance imaging methodology

Moser

Stadlbauer

Windischberger

et al. 2008

Eur J Nucl Med Mol Imaging

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“…There are some studies on adverse health effects related to MRI (11)(12)(13)(14)(15)(16)(17)(18). Among the more recent work are two studies indicating a genotoxic potential of MRI in cell cultures (15;16).…”

Section: Introductionmentioning

confidence: 99%

No effects of MRI scan on male reproduction hormones

Mollerlokken

Moen

Baste

et al. 2012

Reproductive Toxicology

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This is an accepted version of a paper published in Reproductive Toxicology. This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination.Citation for the published paper: Møllerløkken, O., Moen, B., Baste, V., Magerøy, N., Oftedal, G. et al. (2012) "No effects of MRI scan on male reproduction hormones." Reproductive Toxicology URL: http://dx.doi.org/10. 1016/j.reprotox.2012.04.003 Access to the published version may require subscription. A prospective randomized balanced cross-over study using a head scan in real MRI with whole-body transmitting coil and sham MRI among 24 healthy male volunteers was conducted. Serum-blood samples of inhibin B, testosterone, prolactine, thyreotropine, luteinizing hormone, follicle stimulating hormone, sex-hormone binding globuline and estradiol were taken before and after the different scans. Neither immediately after, nor after 11 days were there seen any differences in the hormone levels comparing real and sham MRI. The lack of effects of EMF on male reproductive hormones should be reassuring to the public and especially for men examined in MRI. Adverse effects on other endpoints than male reproduction or possible chronic effect of multiple MRI scans have not been investigated in this study. Abstract (150 words)The use of mMagnetic resonance imaging (MRI) is increasing around the world and the possible adverse effects on reproductive health of electromagnetic fields (EMF) in MRI are not previously studied. We conducted aA prospective randomized balanced cross-over study using a head scan in real MRI with whole-body transmitting coil and sham MRI scan among 24 healthy male volunteers was conducted. Serum-blood samples of inhibin B, testosterone, prolactine, thyreotropine, luteinizing hormone, follicle stimulating hormone, sex-hormone binding globuline and estradiol were taken before and after the different scans. Neither immediately after, nor after 11 days were there seen any differences in the hormone levels comparing real and sham MRI. The lack of effects of EMF on male reproductive hormones should be reassuring to the public and especially for men examined in MRI. Adverse effects on other endpoints than male reproduction or possible chronic effect of multiple MRI scans have not been investigated in this study. Your reviewers have given us valuable comments which my coauthors and I hope to have addressed properly in this letter and in the revised manuscript. We have described our response in the letter and given reference to where in the revised manuscript the changes are. We have also highlighted the changed text in the revised manuscript.We hope you will consider this revised manuscript. Do not hesitate to contact me if anything is unclear. Thank you. Yours sincerelyOle Jacob Møllerløkken Institute of Public Health and Primary Health CareUniversity of Bergen Bergen -Norway *Response to Reviewer CommentsReviewer #1:This is an interesting manuscript with relevance to human patients. The authors conducted a randomized...

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Review of Patient Safety in Time-Varying Gradient Fields

Cited by 216 publications

References 27 publications

A comparison between human magnetostimulation thresholds in whole‐body and head/neck gradient coils

A comparison between human magnetostimulation thresholds in whole‐body and head/neck gradient coils

Magnetic resonance imaging methodology

No effects of MRI scan on male reproduction hormones

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