Is the magnetic resonance imaging contrast agent gadoteric acid ototoxic?

OBJECTIVE: Contrast Magnetic Resonance Imaging (MRI) reveals endolymphatic hydrops in both symptomatic and asymptomatic ears. Radiological visualization of hydrops is important in the diagnosis of Meniere's disease; however, the ototoxicity of intratympanically administered gadoteric acid remains unknown. To investigate the ototoxicity of the intratympanic administration of gadoteric acid at different doses using an Auditory Brainstem Response (ABR) test and histopathological methods. METHODS: Forty healthy male Wistar Albino rats were randomly divided into four groups. The effect of different dilutions of gadoteric acid on the inner ear was examined using the ABR test at 10, 16, and 24 kHz. Basal measurements were compared with those at 1 and 14 days after injection. After completing the final measurements, the rats were sacrificed, and samples were taken for histopathological examination under light microscopy. RESULTS: Following the intratympanic administration of gadoteric acid in rats, the ototoxicity was evaluated on days-1 and -14 based on ABR testing and histopathological examination. The ABR measurements demonstrated that pure gadoteric acid caused a significant decrease in the hearing threshold at 10, 16, and 24 kHz. By contrast, threshold shifts were not significant with diluted preparations. Histopathological examination revealed no significant differences. CONCLUSION: Ototoxicity was detected on day-14 following the intratympanic administration of undiluted gadoteric acid, determined by ABR testing. The dilution of gadoteric acid with saline at a 1:16 ratio appeared to be the safest dose. The level of evidence of this article is 5. This article is an experimental animal and laboratory study.