Gadolinium toxicity: epidermis thickness measurement by magnetic resonance imaging at 500 MHz

Purpose: Regional epidermal thickening and hair follicle width measurement by delayed gadolinium contrast magnetic resonance imaging (MRI) may assess the contrast agent gadolinium toxicity on mice skin. Materials and methods: Delayed contrast in vivo MRI was performed in mice. Six mice skin samples were removed and exposed to a gadolinium contrast agent at different times after 2, 4, 6 and 8 h. The relaxation constants of each skin structure were measured. The thickness of the epidermis and hair follicle on follow‐up ex vivo delayed‐contrast MRI served as an index of gadolinium toxicity on the skin. Results:In vivo MRI by fast low‐angle shot imaging technique showed distinct skin layers. High‐resolution gradient echo T1‐weighted and multislice multiecho proton density‐weighted MRI intensities in the epidermis and hair follicle showed a positive correlation with delayed gadolinium‐enhanced MRI hyperintensities (Pearson's correlation coefficient r 2 =0.81, P <0.0001) in the excised mice skin tissues. Delayed contrast‐enhanced mice skin MRI after 2–4 h showed epidermis swelling and hair follicle regions with a size measurement accuracy of 65%, a sensitivity of 95%, a specificity of 25%, a positive predictive value of 65% and a negative predictive value of 65%. Areas under the receiver operating characteristic curves by MRI were 0.92–0.94 for hair and epidermis as good discriminators. MRI visualized distinct relaxation constants of the epidermis, sebaceous gland, skin papillary and reticular dermis layers and hair follicle. Conclusion: Gadolinium contrast‐enhanced MRI may visualize the thickening of the epidermis wall and hair follicle as an index of viable mice skin. Gadolinium enhanced the MRI visibility of skin structures. Gadolinium treatment showed skin toxicity as epidermis thickening the first time due to the undesirable use of high concentrations of gadolinium in microimaging.