Clinical significance of posterior expansion of the utricular endolymphatic space.

Background: Posterior expansion of the utricular endolymphatic space (ES) is a finding occasionally observed, and often occurs in bilateral ears. The clinical significance of posterior expansion of the utricular ES is not clear.

Objectives: To investigate the clinical significance of posterior expansion of the utricular ES detected on magnetic resonance imaging (MRI).

Materials and methods: Among 957 patients who underwent contrast-enhanced MRI to investigate the presence of endolymphatic hydrops (EH), clinical findings in cases with posterior expansion of the utricular ES were evaluated and the significance of their existence is considered.

Results: Posterior expansion of the utricular ES was detected in 30 ears from 20 cases (7 males, 13 females; mean age 48.7 years). The ears with posterior expansion had a significantly lower incidence of vestibular EH than those without, and this tendency was more prominent in cases in bilateral ears. Some cases with posterior expansion had vestibular symptoms and were diagnosed with Ménière's disease, although EH was not detected in their vestibules.

Conclusion and significance: Posterior expansion of the utricular ES was associated with Ménière's disease without vestibular EH. Posterior expansion of the utricular ES might not be associated with the formation of EH but may occur independently.