Metallic fibers are sometimes incorporated in clothing to keep odor and bacteria from building up. Examples include socks and athleisure (yoga) clothing. However, these fibers can burn the skin if worn in an MRI scanner.
Metal produces heat in a magnetic field. Unfortunately, one 11-year-old girl found out the hard way. She was sedated during an MRI for scoliosis, but when she woke up, she felt burning on her skin. She received a second-degree burn from silver microfibers in her undershirt.
Clothing that says “anti-microbial” or “anti-bacterial” in the label should be avoided in an MRI scanner.