To make their safety determinations, researchers placed each FFP-3 mask on a 3D head phantom and put it into the MRI machine at the Cardiff University in the United Kingdom. They compared the images to images of the 3D head phantom without a mask to measure displacement, considering the model with the mask as a “moving” image and without the mask as a “fixed” image.
Additionally, the researchers positioned temperature strips at the nasal bridge of the phantom. While they did not observe local heating for any of the masks—including one with an aluminum nose strip—they could not rule out the risk of local heating if using a higher specific absorption rate or a head and neck coil.
In general, the authors noted, pandemic-related requirements to wear a respirator or facemask were quickly put into place, meaning that many practitioners did not previously consider the potential risks or complications of wearing one.
“As a result, hospital staff may not be aware of the potential hazards these masks could pose and that MRI safety documentation does not exist.”
One best practice that the authors recommended is to order “MRI safe” surgical masks in a separate color for easy identification.
1. Keenan, BE, Lacan, F, Cooper, A, et. al. MRI safety, imaging artefacts, and grid distortion evaluated for FFP3 respiratory masks worn throughout the COVID-19 pandemic. Clinical Radiology, 2022. DOI: https://doi.org/10.1016/j.crad.2022.05.001.