Association Between Endolymphatic Hydrops as Revealed by Magnetic Resonance Imaging and Caloric Response

Objective: To investigate the association between the degree of endolymphatic hydrops (EH) revealed by magnetic resonance imaging (MRI) and a caloric response in the ear. Study Design: Prospective diagnostic study. Setting: University hospital. Patients: Twenty-four patients with hearing loss and/or vertigo, who underwent MRI 1 day after an intratympanic gadolinium injection. Intervention: MRI after intratympanic gadolinium injection and caloric testing with cool air stimulation (15 degrees C, 6 l/min, 60 s). Main Outcome Measure: Association between the degree of EH and caloric responses. The degree of EH in the vestibule, in the cochlea, and in the ampulla of the lateral semicircular canal (LSC) was evaluated using MRI. The ratio of the diameter of the endolymphatic space to the diameter of the perilymphatic space was measured in the LSC ampulla. Results: Canal paresis (CP, >25%) was present in 15 patients and absent (CP, <25%) in 9 patients. There was no significant difference between caloric response and the degree of EH in the vestibule, the cochlea, or the LSC ampulla. The period between the onset of clinical symptoms and examination tended to be longer in the group with CP compared with the group without CP. Conclusion: There was no significant association between the degree of EH and caloric response.