Pooled analyses of effects on visual and visuomotor performance from exposure to magnetic stray fields from MRI scanners: Application of the Bayesian framework

Vocht, Frank de; Glover, Paul; Engels, Hans; Kromhout, Hans

doi:10.1002/jmri.21142

Cited by 26 publications

(19 citation statements)

References 39 publications

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“…The control population in that study reported at least one SMF core and/or SMF target symptom in 1 % and 25 % of shifts, respectively. We did not observe an association of increased prevalence of symptoms with increasing exposure, which puts these results at odds with previous studies [6][7][8] and with experimental work [11,12,29,30]. Possibly this may be ascribed to the fact that the variation in exposure in our study was not large enough; we only had staff working with 1.5 T or 1.5 T and 3 T systems, while other studies included exposures ranging from 0 (non-exposed controls) up to 7 T. However, reporting of the reference symptoms decreased with increased magnet strength, which may suggest some residual confounding we could not correct for.…”

Section: Discussioncontrasting

confidence: 99%

“…Similarly, for patients, unpleasant effects (dizziness and vertigo, for example, but also tachycardia and sweating), some of which are related to the static field, are reported more often during imaging using 7 T systems than with 1.5 T systems [9]. Some of these reported effects may be related to adverse effects on visual perception, spatial orientation, visuomotor performance, working memory, and attention, measured in controlled trials [10][11][12][13]. Experimental studies similarly show that exposure to the static magnetic field has a direct negative, but temporary, effect on the vestibular system [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

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Transient health symptoms of MRI staff working with 1.5 and 3.0 Tesla scanners in the UK

et al. 2015

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Objectives Recent studies have consistently shown that amongst staff working with MRI, transient symptoms directly attributable to the MRI system including dizziness, nausea, tinnitus, and concentration problems are reported. This study assessed symptom prevalence and incidence in radiographers and other staff working with MRI in healthcare in the UK. Methods One hundred and four volunteer staff from eight sites completed a questionnaire and kept a diary to obtain information on subjective symptoms and work practices, and wore a magnetic field dosimeter during one to three randomly selected working days. Incidence of MRI-related symptoms was obtained for all shifts and prevalence of MRI-related and reference symptoms was associated to explanatory factors using ordinal regression. Results Incident symptoms related to working with MRI were reported in 4 % of shifts. Prevalence of MRI-related, but not reference symptoms were associated with number of hours per week working with MRI, shift length, and stress, but not with magnetic field strength (1.5 and 3 T) or measured magnetic field exposure. Conclusions Reporting of prevalent symptoms was associated with longer duration of working in MRI departments, but not with measured field strength of exposure. Other factors related to organisation and stress seem to contribute to increased reporting of MRI-related symptoms. Key Points • Routine work with MRI is associated with increased reporting of transient symptoms • No link to the strength of the magnetic field was demonstrated.• Organisational factors and stress additionally contribute to reporting of MRI-related symptoms

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Section: Discussioncontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transient health symptoms of MRI staff working with 1.5 and 3.0 Tesla scanners in the UK

et al. 2015

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“…No significant effects on cognitive function were found at any field strength or condition [35 • ]. In contrast, studies by the group of De Vocht showed some small but significant effects on attention/concentration and visuospatial orientation when the subject was positioned in the stray field of a 7 T scanner both when stationary and also after moving their head [36,37]. Bearing in mind the recent studies, discussed previously, on nystagmus, it would be interesting to investigate whether this could explain the observed cognitive effects in the visuospatial and attention/concentration domain, and to replicate the possible relation between nystagmus and these cognitive effects in a magnetic field free environment during vestibular activation [38].…”

Section: Biological Effects Of the Main Magnetic Field Strengthmentioning

confidence: 89%

Safety of Ultra-High Field MRI: What are the Specific Risks?

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Webb

2014

Curr Radiol Rep

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There are currently more than 50 ultra-high field (7 T and above) MRI systems installed around the world. The vast majority of these perform studies on humans, whether healthy volunteers, volunteers for clinical research, or actual patients. The increased magnetic field strength potentially raises new safety concerns in the areas of the effects of the static magnetic field itself, increased power deposition due to the higher operating frequency, and acoustic noise. There are currently very different operational modes in different institutions, with policies effectively set by local ethics committees. This article summarizes the current legal and practical status regarding safety of ultra-high field MRI.

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“…The (long-term) health significance of these acute neurobehavioral effects and reported symptoms among employees who repetitively work near MRI systems is as yet unknown. Nevertheless, these dose-dependent effects [15][16][17] could potentially lead to accidents and errors by workers that are harmful for themselves or for patients under their care, for example during MRI-guided interventional procedures. If the authors would have recognized these in their review they would have been able to update their 'conventional' safety recommendations with advice on how to limit the incidence of these transient effects among personnel and hence potential errors and accidents resulting from them.…”

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confidence: 98%

Health Effects and Safety of Magnetic Resonance Imaging

et al. 2011

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Dear Sir, With interest we took note of a review on health effects and safety of Magnetic Resonance Imaging by Drs Ng, Faust and Acharya U, published online on March 30 2010 in the Journal of Medical Systems [1]. As adequately described by the authors there are a wide number of advantages to the use of MRI as a medical imaging modality that have led to improved diagnostic outcomes without the drawbacks of for example the use of X-rays; hence the exponential growth in usage since its first introduction in the late 1970s [2]. Nonetheless, there are several serious drawbacks related to the strong static and time-varying magnetic fields and radiofrequency fields required for scanning which as discussed by the authors require specific safety recommendations.Unfortunately, set out as a review of current knowledge of adverse health effects and current safety issues related to MRI environments for both patients and staff members this review fails to achieve its aim. Surprisingly, the most recent non-self citation reference to peer-reviewed work is from 2007 despite ongoing research since then. As such, it is no surprise that the safety recommendations provided by the authors focus on prevention of accidents due to ferromagnetic objects and implants, (local) tissue heating and reduction of acoustic noise, which were the only notable risks associated with MRI identified at the end of the previous century [3].However, since the publications cited by the authors an additional body of work (of which the first peer-reviewed papers were in fact already published in the period supposedly covered in the review) into acute transient adverse effects related to exposure to the static and time-varying magnetic fields present in, but also surrounding MRI systems has emerged. Controlled human trials [4][5][6] have provided evidence that visual perception and visuo-motor performance are negatively affected during movement (of the head) in the heterogeneous static magnetic stray field surrounding MR systems. A more recent study has also shown that different cognitive domains can also be affected by time-varying magnetic fields [7]. In line with proposed biological mechanisms for these effects [8,9] no effects were observed within the homogeneous magnet bore, where patients are located during scanning [10] nor were effects on cognition measurable immediately after exposure had ended [11]. However, recent data from a controlled trial using transcranial magnetic stimulation (TMS) does suggest a transient alteration in cortical excitability after undergoing an MRI scan and exposure has ended [12]. Although a threshold level seems to exist for at least some of the acute effects [13], effects could already be measured well below the 2 T and 6 Ts −1 limits mentioned in this review (although appropriate limit values would instead have been the most recent ICNIRP guidelines [14]). Field surveys have further shown that MR engineers [15] and nurses [16] routinely working with MRI scanners regularly experience adverse transient effects including

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Pooled analyses of effects on visual and visuomotor performance from exposure to magnetic stray fields from MRI scanners: Application of the Bayesian framework

Cited by 26 publications

References 39 publications

Transient health symptoms of MRI staff working with 1.5 and 3.0 Tesla scanners in the UK

Transient health symptoms of MRI staff working with 1.5 and 3.0 Tesla scanners in the UK

Safety of Ultra-High Field MRI: What are the Specific Risks?

Health Effects and Safety of Magnetic Resonance Imaging

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