Abstract
Intratympanic steroids therapy has been widely used to treat inner ear diseases such as sudden sensorineural hearing loss and Ménière's disease. We administered gadolinium contrast agents (Gd) intratympanically and performed magnetic resonance imaging (MRI) to investigate how the drug distributes in the inner ear. Gd signal intensity in the inner ear showed wide individual difference after the intratympanic Gd injection. The individual difference may depend on the degree of the permeability through the round window membrane. Two patients underwent exploratory tympanotomy because the Gd movement into the inner ear was poor. In these patients, we removed the overhanging bone to visualize the round window membrane and observed good round window reflex when the stapes was touched. In one patient, however, Gd movement from the middle ear into the inner ear could not be obtained. These results indicated that evaluation of the permeability through the round window membrane was difficult even though accessibility to the round window membrane could be established by the surgery. Intratympanic Gd injection and MRI provide useful information for intratympanic drug therapy for the treatment of inner ear diseases.
