Electromagnetic Exposure of Personnel Involved in Cardiac MRI Examinations in 1.5T, 3T and 7T Scanners.

Katarzyna Sklinda,Jolanta Karpowicz,Andrzej Stępniewski

doi:10.3390/ijerph19010076

Abstract

(1) Background: It has been hypothesised that a significant increase in the use of cardiac magnetic resonance (CMR), for example, when examining COVID-19 convalescents using magnetic resonance imaging (MRI), has an influence the exposure profiles of medical personnel to static magnetic fields (STmf). (2) Methods: Static exposure to STmf (SEmf) was recorded during activities that modelled performing CMR by radiographers. The motion-induced time variability of that exposure (TVEmf) was calculated from SEmf samples. The results were compared with: (i) labour law requirements; (ii) the distribution of vertigo perception probability near MRI magnets; and (iii) the exposure profile when actually performing a head MRI. (3) Results: The exposure profiles of personnel managing 42 CMR scans (modelled using medium (1.5T), high (3T) and ultrahigh (7T) field scanners) were significantly different than when managing a head MRI. The majority of SEmf and TVEmf samples (up to the 95th percentile) were at low vertigo perception probability (SEmf < 500 mT, TVEmf < 600 mT/s), but a small fraction were at medium/high levels; (4) Conclusion: Even under the “normal working conditions” defined for SEmf (STmf < 2T) by labour legislation (Directive 2013/35/EC), increased CMR usage increases vertigo-related hazards experienced by MRI personnel (a re-evaluation of electromagnetic safety hazards is suggested in the case of these or similar changes in work organisation).

Highlights

Magnetic resonance imaging (MRI) is currently the gold standard for evaluating cardiac morphology and function [1]
This study evaluates the hypothesis that the significant increase in cardiac magnetic resonance (CMR) use observed recently, largely due to the diagnostic needs of patients who have recovered from COVID19, has a significant influence on the profiles of static magnetic fields (STmf) exposure of MRI personnel, which may have an impact on vertigo-related safety hazards experienced inside scan rooms
We developed a simplified system of categorisation regarding the probability of hazards associated with vertigo perception near MRI magnets using a threelevel scale according to various exposure metrics (SEmf and TVEmf), assessable by exposimetric measurements

Summary

Introduction

Magnetic resonance imaging (MRI) is currently the gold standard for evaluating cardiac morphology and function [1]. Recent cardiac magnetic resonance (CMR) mapping techniques, including T1, T2 and extracellular volume, are unique tools for quantitative assessments of myocardial diffuse fibrosis and edema [2]. The ongoing COVID-19 worldwide pandemic caused by the SARS-CoV-2 coronavirus (with the number of cases still rising rapidly worldwide—from over 1 million cases in April 2020 to over two hundred million by August 2021) has affected nearly every aspect of life, at least during 2020 and 2021, but it has not stopped MRI diagnostics, even of infected patients [3,4]. The scope of examinations performed using MRI scanners in many diagnostic units has recently changed significantly due to the rapid growth of specific clinical conditions that were not as commonly diagnosed before the pandemic. According to published studies [5,6], up to 15% of patients with

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