The Predominant Vestibular Uptake of Gadolinium Through the Oval Window Pathway Is Compromised by Endolymphatic Hydrops in Meniere's Disease

Objective: Intratympanic administration of gentamicin is becoming a common therapy to control vertigo in Meniere's disease (MD). Drug entry through an oval window pathway was recently demonstrated in rats. The present study aimed to evaluate the permeability of the oval window to gadolinium in MD patients. Methods: Eight patients with MD and other inner ear diseases received a transtympanic injection of 5-fold diluted gadopentetate dimeglumine (Gd-DTPA). Three-dimensional fluid-attenuated inversion-recovery (3D-FLAIR) and 3D inversion recovery turbo spin echo with real reconstruction (3D-real IR) imaging was performed using a 3-Tesla MRI scanner at 3, 6, 12, and 24 h after injection. The extent of vestibular endolymphatic hydrops (EH) was determined, and the dynamics of the signal changes in the vestibule and the cochlear basal turn were evaluated. Results: Transtympanically injected Gd-DTPA entered the cochlea of all 8 of the patients and entered the vestibule of 7 of the 8 patients. EH was demonstrated in 2 patients with MD and the patient with idiopathic sensorineural hearing loss or idiopathic vertigo. In the patients lacking EH, the vestibules exhibited more efficient uptake of Gd-DTPA than did the cochleae. In the patients with vestibular EH, the Gd-DTPA signal in the vestibule was less intense than that in the cochlear basal turn. Conclusion: In patients with inner ear diseases, the vestibular distribution of Gd-DTPA was compromised by vestibular EH, suggesting oval window passage of Gd-DTPA is reduced in the presence of EH.