Imaging Evaluation of Endolymphatic Hydrops in Cases with Otosclerosis

Abstract

Objectives: Human temporal studies have shown that endolymphatic hydrops (EH) is accompanied by otosclerosis, which is a risk factor for complications after stapes surgery. Recently, visualization of EH has become possible using magnetic resonance imaging (MRI) with contrast agents. The presence of EH in cases with otosclerosis was investigated by MRI to prevent complications following stapes surgery. Methods: Sixteen ears from nine cases diagnosed as having otosclerosis were evaluated by 3-Tesla MRI examinations taken 4 h after intravenous gadolinium injection. More than half of the ears showed mixed hearing loss and were suspected to have cochlear otosclerosis. Imaging data were compared with clinical findings in all ears and postoperative symptoms in ears undergoing surgery. Results: Varying degrees of EH were observed in 14 of the 16 ears. Episodes of acute sensorineural hearing loss or vertigo occurred in 4 ears with severe EH in the cochlea and 3 ears with severe EH in the vestibules. Overall, 12 of 14 ears with EH did not undergo stapes surgery. Ears without EH showed no postoperative complications, but one ear with mild EH in the vestibule showed severe vertigo following the surgery. Conclusions: The presence of EH in cases with otosclerosis was clearly visualized, and the degree of EH was correlated with the clinical findings in most patients. Such preoperative MRI evaluation could provide useful information to prevent complications following stapes surgery.