Multifaceted Evaluation of Ultra-high-field 9.4-T Magnetic Resonance Imaging after Inorganic Tattoos: An Animal Study

Introduction: Tattooing techniques for reconstruction and rectification of the sequelae of cancer treatments, surgery, and scarring have received attention in the medical field. There is concern that tattooed skin is at risk of being burned by magnetic resonance imaging (MRI) examination. However, a detailed evaluation of the impact of MRI imaging on medically tattooed skin has not yet been performed. This study aimed to clarify the changes in common inorganic tattoo pigments during MRI examinations in an animal model.Methods: Tattooed hairless mice with eight typical pigments for tattoos were evaluated for changes in temperature, color tone, and histology of the tattoos during a 9.4-T MRI.Results: None of specimens had signs of burns, such as redness or blisters. In terms of temperature changes, the black iron oxide and carbon black specimens had a maximum temperature increase of 0.4 degrees. In the Munsell color system, no specific color changes were observed before or after the MRI. Color changes, evaluated as the ΔE 00 in the L * a * b * color space, were all below 3.0 and were thus regarded as being indistinguishable and within the color unevenness of the tattoo. Histologic analysis of the specimens showed no significant changes before and after the MRIs.Conclusions: The observed temperature changes, color tone changes, and histological changes in the tattooed areas in this animal model were not of a magnitude considered likely to adversely affect the human body.