Correlation of Endolysmphatic Duct Signal Intensity With Clinical Features in Otological Diseases

Objective Bilateral high signal intensity (SI) in the endolymphatic duct (ED) on magnetic resonance imaging (MRI) has been reported as a common characteristic in ears with large vestibular aqueduct syndrome (LVAS). However, the significance of bilateral high SI in the ED remains unknown. The present study aimed to compare the correlation between SI in the ED and the clinical manifestations in various otological disorders and consider the significance of the MRI findings. Study Design Retrospective study. Setting University hospital. Patients The study included 2,450 ears from 1,225 patients with various otological disorders. Intervention All ears underwent 3T enhanced MRI and were evaluated for the degree of endolymphatic hydrops (EH) and the SI ratios (SIRs; i.e., the calculation between SIs in the ED and those in the cerebellum). Main Outcome Measure The imaging findings were compared with their clinical symptoms. Results Ears with bilateral high SIRs in the ED tended to have considerably less occurrence of EH in both the cochlea and vestibule than those with bilateral low SIRs. Ears with SIR ≥8 showed significantly elevated hearing thresholds at lower frequencies on pure-tone audiometry, although they exhibited a markedly lower incidence of cochlear EH than those with SIR <8. Moreover, ears with vertigo exhibited notably higher SIRs than those without vertigo. Conclusion Bilateral high SI in the ED on MRI may reflect pathophysiology underlying sensorineural hearing loss and vestibular symptoms, which are not associated with EH formation.