Association of contrast-enhanced MRI of inner ear and caloric response in patients with clinically diagnosed ipsilateral delayed endolymphatic hydrops

Background: Patients with delayed endolymphatic hydrops (DEH) often show caloric hypofunction and endolymphatic hydrops (ELH) on gadolinium (Gd) enhanced magnetic resonance imaging (MRI) of the inner ear.

Objectives: We aimed to investigate the relationship between the ELH in vivo and caloric results in ipsilateral DEH.

Material and methods: Twelve patients with ipsilateral DEH were included, who underwent delayed MRI following intratympanic Gd application, pure-tone audiometry, caloric test, and video head impulse test (vHIT).

Results: For the affected ears, the overall prevalence of inner ear hydrops was 91.7%, including 75% in the cochlear and 50% in vestibular compartment. For the non-affected ears, the overall prevalence of inner ear hydrops was 25%, including 25% in cochlear and 16.7% in vestibular region. Caloric hypofunction was demonstrated in 75% of the affected ears. No pathologic vHIT were found. Caloric results were in agreement with the radiological evidence of inner ear hydrops on affected and non-affected ears in 9 cases. There was fair concordance between inner ear hydrops and canal paresis abnormality on the affected side.

Conclusions and significance: MRI provides auxiliary evidence of ELH in vivo in the ipsilateral DEH-affected ears. The association between morphological alterations and caloric hypofunction warrants further investigation.