Artifacts on temporomandibular joint MR images caused by mascara used as hair dye

We report the case of a patient who used mascara in an unusual manner, as hair dye, causing artifacts on magnetic resonance (MR) images. A 60-year-old woman was referred to our hospital because of discomfort and mastication difficulty as a result of dislocation of the mandible on the left side. After a general examination, she was diagnosed with temporomandibular joint disorder and MR imaging was performed. The images showed artifacts in the bilateral temporal regions, although the patient had not undergone surgical treatment in the region and there were no metal hair accessories. However, mascara had been applied to the region to dye the patient’s hair black. To verify that mascara could be the cause of the artifacts in the temporomandibular area, we performed mock MR imaging using a phantom and mascara. Artifacts were also observed in the area with mascara, confirming that the mascara caused the artifacts during MR imaging. This case suggests that care should be taken during MR imaging when different cosmetics are used in the head and neck region.