Volume ratio and distribution rate in patients with orthostatic vertigo/dizziness using MR imaging: a comparison with vertiginous diseases

BackgroundOrthostatic dizziness/vertigo (ODV) is characterized by lightheadedness owing to postural changes.Aims/ObjectivesTo measure the endolymphatic space (ELS)/total fluid space (TFS) volume ratio and the distribution rate of endolymphatic fluid (ELF) of patients with ODV and compare them with those of control subjects (CS).Materials and MethodsThis study included 22 patients (44 ears) with ODV and 52 controls (104 ears, CS). The ELS/TFS volume ratio (%) and distribution rate (%) of the inner ear components were measured using 3-dimensional magnetic resonance imaging.ResultsIn the ODV group, the mean ELS/TFS volume ratios of the cochlea, vestibule, and semi-circular canals (SCCs) were 12.1%, 18.6%, and 18.1%, respectively; the mean ELS distribution rates for the cochlea, vestibule, and SCCs were 27.3%, 26.2%, and 46.6%, respectively. The ELS distribution rate of the vestibule was significantly lower (p < .01) and the ELS distribution rate of the SCCs was significantly higher in the ODV than in the CS group (p < .01).Conclusions and SignificanceThe ELS distribution rate in the vestibule + SCCs among patients with ODV did not differ from that in the CS; ELF in the vestibule moved to the SCCs, and a large amount of ELF was distributed only in the SCCs.