MRI safety for leave-on powdered hair thickeners under 1.5-T and 3.0-T MRI: measurement of deflection force, MRI artifact, and evaluation of preexamination screening.

This study aimed to clarify the magnetic resonance imaging (MRI) compatibility of leave-on powdered hair thickeners by evaluating the displacement force and image artifacts of commercially available leave-on powdered hair thickeners on MRI devices and their response to metal and ferromagnetic detectors. Thirteen types of leave-on powdered hair thickeners were studied: nine hair thickener and four foundation types. MRI systems of 1.5 T and 3.0 T were used. Deflection angles and MR image artifacts according to ASTM F2052 and F2119 were evaluated. Handheld metal and ferromagnetic detectors were used to investigate whether hair thickeners could be detected in screening before MRI examinations. The hair thickener type had a deflection angle of 0°, whereas the foundation type had a deflection angle of 90°, indicating a strong physical effect. Significant image artifacts appeared only on the foundation type. The foundation type reacted at distances of less than 10 cm only with a ferromagnetic detector. Foundation-type leave-on powdered hair thickeners containing magnetic substances exhibited strong physical effects and produced significant image artifacts, and those can only be detected by screening with a ferromagnetic detector.