Helen Heng Yang, MRT (MR) (R)*, Melissa F. Charette, MRT (MR) (R), BSc and Nancy Talbot, MappSc, MRT(MR) (R)
Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
Keywords: MRI; safety; patient preparation; burn; policy; education; practices; metallic microfiber
Silver and copper microfiber-embedded textiles are used to control odor through antibacterial properties, and their use has become increasingly common . When silver or copper come into contact with body fluids, they release metallic ions that kill microbes and bacteria . An increased number of clothing items are incorporating metallic microfibers into clothing material ranging from athletic apparel to socks and orthotics . In Canada, these products are sold under various brandsdincluding, but not limited todReebok, Adi- das, Knixwear, Mark’s Work Warehouse, Lululemon, Tommy Copper, Pere-tex, and Microban [2–6].
Many patients intentionally wear metal-free clothing to their magnetic resonance imaging (MRI) appointment so that they do not have to change into hospital-provided attire. However, the invisible metallic microfibers are conductive materials. When they present in the magnet during the scan acquisition, the material can heat up, resulting in burn injuries to patients undergoing the procedure . In 2013, Pietryga et al reported a case where a patient underwent an MR scan wearing an under- shirt containing silver microfibers and sustained cutaneous burns. The burns were caused by heating in the silver microfib- ers because of electromagnetic induction of the radiofrequency (RF) electromagnetic pulses . When the changing magnetic flux lines intercept an electrically conductive loop (a.k.a. loop formed by silver microfibers), eddy currents are induced in the loop . The induced current generates heat due to ohmic
The author(s) has no financial disclosures or conflicts of interest to declare. * Corresponding author: Helen Heng Yang, MRT (MR) (R), Joint Depart- ment of Medical Imaging, University Health Network, 190 Elizabeth Street Tor-
onto, Ontario M5G 2C4, Canada.
E-mail address: firstname.lastname@example.org (H.H. Yang).
heating. The worst electromagnetic induction heating occurs when the conductive loop is in a resonant condition (oscillating
frequency is 1= LC , where L is inductance and C is capaci-
tance of the conductive loop) .
Another possible heating mechanism to explain why
metallic microfibers can heat up during MR scan is due to the antenna effect . Conductive material like metallic microfibers can act as an antenna, which captures the electro- magnetic waves to extract power from them. Resonance is achieved when the length of the antenna is approximately half of the RF wavelength . Resonant antenna induces additional electric fields in the conductive material and pro- duces energy as heat . The energy produced is usually confined to the tip of the conductive material. Dempsey et al  have demonstrated significant temperature rise due to resonant circuit and antenna effect. Therefore, when metallic microfibers form loops that meet the resonant circuit criteria, or when the microfibers have a length that is equiva- lent to half of the RF wavelength, burn injuries can happen.
Many MRI facilities in the United States allow patients to wear their own loose-fitting clothing during MR examinations . We investigated current practices among MRI technolo- gists in Canada to get an idea of current practices and the level of awareness MRI technologists have regarding clothing material-related burns. In this communication, we report re- sults from a survey exploring other factors that may influence technologist practices, such as work experience and institu- tional policy, and make recommendations where appropriate.
An anonymous survey of ten questions (see Appendix) was created using Survey Monkey by members of the University Health Network MRI team and sent out to MRI
1939-8654/$ - see front matter ! 2016 Canadian Association of Medical Radiation Technologists. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jmir.2016.04.001
technologists currently practicing in Canada. The study was approved by the University Health Network research ethics board. Implied consent was obtained from all participants. A brief explanation on the purpose of the study and rights of the participants were stated in the first page of the survey. Participants were given the option to choose not to participate in the survey, or to opt out of answering any questions they considered inappropriate. The survey link was initially adver- tised on the Canadian Association of Medical Radiation Technologists (CAMRT) Twitter and Facebook accounts, and then sent out by the CAMRT to all members registered as MRI technologists through a mass e-mailing.
A total of 246 responses were received. All data were exported from Survey Monkey and stored in a password- protected Excel file. Among the 246 survey responses collected, 35 were incomplete. These incomplete survey re- sponses had more than one question left unanswered and were therefore excluded from the data analysis.
Results demonstrated that when patients arrived for an MR scan wearing a plain T-shirt and stretch pants, 56% of technologists would ask them to change into hospital attire (regardless of what the patient was wearing). Twenty-five percent would ask patients to get changed based on the type of examination to be performed. Since there was no metal on the patient, 17% of technologists would not ask them to get changed. Lastly, 2% would only ask patients to get changed if their examination was planned for a stronger mag- net (see Figure 1).
Technologist Awareness of Clothing-Related Burn Injuries
Results showed that 78% of technologists had heard of, or had encountered material-related burns, while 22% of tech- nologists were not aware of such incidences. Among the 78% of technologists who had heard of, or encountered burn incidence, 26% were able to explain that the burn was caused by metallic fibers inside the magnet where the chang- ing RF and/or magnetic fields induces a current within the fi- bers, and as a result, generates heat. Thirty-eight percent of
change paent if paent is scanned on a stronger magnet
technologists knew that metallic fibers on clothing can cause burns when inside the magnet but failed to explain the physics-related rationale. Nine percent of technologists ex- plained why burns can happen inside the magnet but failed to mention that clothing-related burns are caused by metallic fibers. Twenty-seven percent of technologists were not able to identify the source for the burn or explain the rationale.
Factors such as years of working MRI experience, site policy, and burn awareness were analyzed for statistical significance us- ing Pearson’s chi-square test to determine if there was any rela- tionship between each factor and technologists’ practices.
There was no significant relationship between years of working experience and the technologist’s practice (chi-square 9.01, P 1⁄4 0.342), as summarized in Table 1. Nevertheless, one interesting fact to note from observed data is that people who had worked more than 20 years were less likely to ask patients to get changed (based on the types of examinations performed); whereas people who had worked between 6 and 10 years were more likely to ask their patients to get changed.
Table 2 represents the relationship between the existence of a site policy and technologists’ practices. At sites where there is a policy on changing patients, technologists were more likely to always ask their patients to change, while at sites where there is no policy (or technologists are not aware of the pol- icy), technologists did not ask patients to change as often.
Table 3 illustrates the relationship between technologists’ awareness regarding clothing burn incidence and their own practices. Most observed data show that there was no relation- ship; however, the observed value in the cell ‘‘not aware and no change required’’ was much higher, showing that technol- ogists who were not aware of burn incidence were more likely to not ask patients to get changed. The discrepancies between high awareness and low compliance could be due to a few fac- tors; for example, patient’s mobility level, patient’s scheduling issues, and staffing issues. Technologists may be more reluc- tant to ask patients to change if those patients have difficulty changing by themselves. When technologists are running behind schedule due to double bookings, emergency add- ons, or are short staffed, they may choose not to change patients to try to save time and catch up. To find out which factors truly affect technologist’s practices, further surveys should be conducted.
The high percentage (78%) of technologists who had heard of, or encountered, burn incidence could be due to a related story in the Canadian popular press where a patient undergoing a breast MRI in an Ontario hospital site felt a burning sensation on her legs during the scan. After removing the yoga pants she was wearing, she tried the scan again, and this time with no burning sensation . These types of stories tend to spread quickly among the MRI technologist commu- nity. However, even with this level of awareness, only about 56% of the technologists surveyed would always ask patients to get changed into hospital attire for all examinations.
no need to change 2% 17%
change paent based on the type of examinaon being performed
always change paent 56%
Figure 1. Technologist practices distribution pie chart.
H.H. Yang et al./Journal of Medical Imaging and Radiation Sciences 47 (2016) 124-128 125
Years of Working Experience vs. Practices
Years of Working Experience
0–5 Years 6–10 Years 11–15 Years 16–20 Years More than 20 Column totals
Technologists Practices Always
33 (34.20; 0.04) 26 (30.21; 0.59) 23 (25.08; 0.17) 18 (14.25; 0.99) 18 (14.25; 0.99) 118
16 (15.36; 0.03) 18 (13.57; 1.45) 13 (11.27; 0.27) 4 (6.40; 0.90)
2 (6.40; 3.03) 53
No Change Required
11 (10.43; 0.03) 9 (9.22; 0.01) 8 (7.65; 0.02) 3 (4.35; 0.42) 5 (4.35; 0.10)
207 (Grand total)
Relationship between years of working experience and technologists’ practice. Always 1⁄4 always changing patients regardless what patients’ wearing. Sometimes 1⁄4 would change patients based on the type of examinations performed. No change required 1⁄4 no need to change since patients have no metal on.
Of the 25% of technologists asking patients to get changed based on the types of scans being performed, most of them did not ask if the patient was planned for a head examination; however, depending on the MRI scanner vendor and model, many perform brain examinations using the ‘‘receive only’’ head coil. The RF transmission is done by the body coil in this instance. The transmission of RF and gradients are not confined to brain only and the energies are also sent to the rest of the body that is within the length of the RF body coil during the scan. There is a chance that clothing contain- ing metallic microfiber can still heat up during a brain exam- ination. Therefore, it is important to always change the patient regardless of the type of scan being performed.
One of the limitations of this study is that self-selection sampling was used for the research design. The survey was sent out to CAMRT members through Twitter/Facebook and e-blast and all registered MRI technologists within the or- ganization were invited to take part on their own accord. The disadvantage of self-selection sampling method is that there is likely to be a degree of self-selection bias. The ones who chose to complete the forms could suggest a bias toward those who feel confident of their practice or those with a generally higher commitment to patient and professional issues. This could lead to the sample not being representative of the population being studied or exaggerating certain findings from the study.
This survey showed that many clinical sites have existing policies or guidelines for technologists regarding changing their patients for scans. The results indicate that there is a strong correlation between site policy and technologists’ changing patient behavior. It is more likely for technologists working in sites with policies to frequently change their pa- tients. Therefore, it is highly recommended that all MRI clin- ical sites develop policies on changing patients to avoid burn incidence. Many MRI safety policies are written based on the CAMRT Best Practice Guidelines (BPGs) . Under the BPG’s burn prevention section, the precautions to be under- taken to prevent MRI burns are listed; however, changing patients into hospital attire to prevent metallic microfiber- related burns is not mentioned. Therefore, it is recommended to add ‘‘always change patient into hospital attire to prevent metallic microfiber-related burns’’ into the BPGs to ensure safer practices among technologists.
Another way to encourage safer practice is by enhancing technologist knowledge through various continuous profes- sional development methods such as attending safety-related seminars, courses, conferences, and symposiums; reading safety-related journal articles; and watching MR safety videos. Most current safety topics presented are on projectile inci- dence prevention (preventing metallic objects flying into the magnet), MR contrast agent safety, implant safety (eg, scan- ning patients with pacemaker or neurostimulators), pregnancy policy, and cryogen safety . Therefore, although people are frequently attending safety seminars, they may not receive up- dates on burn-related issues. Future education seminars should include more talks focused on burn prevention.
Summary and Conclusion
It is important for MRI technologists to be aware of metallic microfiber-related burn risks and to perform accord- ing to best practices to ensure patients’ safety inside the mag- net. Although 56% of technologists from the survey reported they always ask their patients to get changed (regardless of what they are wearing), close to half of the technologists
Site Policy vs. Practices
I do not
know Column totals
Technologists Practices Always Sometimes
98 (86.65; 1.49) 37 (38.92; 0.09) 12 (19.95; 3.17) 11 (8.96; 0.46)
17 (26.43; 3.37)
12 (6.09; 5.74) 35 7 (3.48; 3.57) 20
8 (11.40; 1.01) 118
5 (5.12; 0.00) 53
207 (Grand total)
No Change Required
H.H. Yang et al./Journal of Medical Imaging and Radiation Sciences 47 (2016) 124-128
Relationship between the existence of site policy and technologists’ prac- tice. Yes 1⁄4 site has a policy or a standard of work on changing patient; no 1⁄4 site does not have policy or standard of work on changing patient; I do not know 1⁄4 technologists’ not sure if site has any policy on changing patient.
Awareness on Burn Incidence vs. Practices
What is the strength of the magnet you use at your facility? (Check all that apply)
B 1.5 T B3T B7T B Other
If a patient arriving for MR scan is wearing a plain T-shirt and stretch pants (a.k.a. no zipper, no hooks, no metallic fasteners, no loose metallic component, or metallic threads), would you still change the patient for the examination? (Choose the one that best repre- sents your practice)
B Yes. I always change my regardless of what they are wearing or what examination they are for.
B Sometimes. Depending on which body part is being scanned, I may change my patient.
B Maybe. I would change my patient if they are being scanned on stronger magnet (eg, 3 T, 7 T)
B No. Patient has no metal on, so can be safety scanned without changing.
If you always change your patients regardless of what they are wearing or what examination they are for, what are the changing instructions you give to all your patients? Would you ever deviate from your routine practice? If so, when?
95 (92.35; 0.08) 23 (25.65; 0.27) 118
43 (41.48; 0.06) 10 (11.52; 0.20) 53
No Change Required
24 (28.17; 0.62) 162
12 (7.83; 2.23) 36
207 (Grand total)
Relationship between incidence awareness and technologists’ practices. Yes 1⁄4 technologists have heard or encountered clothing material-related burn. No 1⁄4 technologists not aware such clothing material-related burn incidence.
reported they do not always change their patients. For patients who can not change themselves because of disability or impaired consciousness, it is important to check the clothing labels. If there is an unknown material labeled, it is always much safer to help patients change into hospital attire. Patients should always be informed about possible heating during the scan and be instructed to squeeze the emergency buzzer immediately if any heating sensation is felt.
Under the BPG ‘‘Burn Prevention’’ section, it states ‘‘Burns are the most common patient injuries to occur in the MRI environment’’ . Preventing burns is among the most important patient safety priorities for MRI technolo- gists. With rapid developments in technology, new inventions such as using metallic microfibers in clothing to reduce odor and infection can be beneficial to Canadian population. How- ever, these new inventions can also pose potential risks for patients undergoing MRI tests. It is important for MRI tech- nologists to be aware of and to understand the new develop- ments and their possible danger. With continuing education, patient safety risk can be minimized.
From the survey conducted, technologists’ behavior regarding changing patients is affected by site policy but not by years of working experience or awareness of clothing material-related burn incidence. Canadian technologists showed good awareness on metallic microfiber-related burn incidences. However, the knowledge on why such incidences could occur was poor. To improve technologists’ knowledge and ensure technologists always ask patients to change into hospital attire, it is recommended to offer more safety educa- tion on burn prevention, add ‘‘changing patients into hospital attire or safe, known materials to prevent burn from metallic microfibers’’ to CAMRT BPGs and to encourage all clinical sites to develop policies on technologist practices regarding patient outfit changes.
1. How many years have you worked in MR? B 0–5 Years
B 6–10 Years
B 11–15 Years
B 16–20 Years
B 20 Years above
*Skip this question if you change your patients based on the types of examinations.
5. If you change your patients based on which body part is
being scanned, which of the after examinations would
prompt you to change your patients? (Check all that apply) *Skip this question if you always change your patients.
B Head and neck
B Extremities (knees, hips, shoulders, and so forth)
B Neurovascular (carotids/cow MR angiography
B MRA of chest/abdomen/pelvis
B MRA of extremities (eg, peripheral leg run-off) B Other
6. When you are changing patients for MR examinations, what is the fabric content of the MRI attire that you are providing to your patients?
B Mix of cotton and polyester B I do not know
7. Does your clinical site have any policies or standards of work with regards to changing patient?
B I do not know
H.H. Yang et al./Journal of Medical Imaging and Radiation Sciences 47 (2016) 124-128 127
Have you heard of or have you ever encountered any clothing-related thermal burn in MR?
If you are aware of clothing material-related thermal
burn risk in MR, can you describe the physics reasoning
behind such an incident?
How often do you attend MR safety-related continuing
education opportunities (ie, symposium, seminar, and webinar)?
B Once a year
B Two to four times a year
B More than five times a year B Other
 Shaw, H. (2013). ‘An underwear upgrade’: Toronto lingerie line Knix Wear gets unexpected crowdfunding boost. Retrieved from Financial Post website on Dec 15, 2015. http://business.financialpost.com/ entrepreneur/knixwear-underwear-toronto.
 Microban International (2013). Invest in Microban Antimicrobial Cop- per Technology for Industrial Grade solution. Retrieved from Microban website on Dec 16, 2015. http://www.microban.com/en-uk/how-we- work-en-uk/technologies-en-uk/copper-antimicrobial1.
 Tafford (2015). Tommie Copper Men’s Innerwear active fit crew neck shirt. Retrieved from Tafford website. http://www. tafford.com/tommie-copper-mens-innerwear-active-fit-crew-neck-shirt. html.
 Marsden, C. (2014). Why some clothes could pose a safety hazard during MRI exams. Retrieved from Global News website on April 30th, 2015. http://globalnews.ca/news/1452176/why-some-clothes-could-pose-a-safety- hazard-during-mri-exams/.
 Dempsey, M. F., Condon, B., & Hadley, D. M. (2001). Investigation of the factors responsible for burns during MRI. J Magn Reson Imaging 13(4), 627–631.
 CAMRT (2015). Best Practice Guidelines - Burn prevention (MRI specific). Retrieved from CAMRT website. https://ww2.camrt.ca/ bpg/patientsafety/mrisafety/burnpreventionmrispecific/ on May 1st, 2015.
 MR safety course (2015). Retrieved from MRI safety course website:
Shahidi, S., & Wiener, J. (2012). Antibacterial agents in textile industry. INTECH Open Access Publisher, Croatia.
Pietryga, J. A., Fonder, M. A., Rogg, J. M., North, D. L., & Bercovitch, L. G. (2013). Invisible metallic microfiber in clothing presents unrecognized MRI risk for cutaneous burn. Am J Neuroradiol 34(5), E47–E50.
H.H. Yang et al./Journal of Medical Imaging and Radiation Sciences 47 (2016) 124-128