MRI-based measurement of inner ear fluids reveals increased endolymph volume variability in patients with endolymphatic hydrops and hearing instability.
Level 3 - non-randomized controlled study
Prospective longitudinal cohort study with a healthy control group.
PubMed 40596438 · doi:10.1038/s41598-025-06083-w
What was done
A prospective cohort study followed 14 patients (aged 29–73 years) with hearing instability over 15 months, alongside 12 healthy volunteers (aged 22–75 years). Contrast Enhanced Delayed (CED)-MRI using 3D FLAIR and STIR sequences was performed every 3 to 6 months alongside standard hearing threshold testing. Perilymph and endolymph volumes were quantified using a semi-automatic MRI processing and analysis pipeline to assess endolymph-to-perilymph (E/P) ratio dynamics.
What was found
Variance in individual E/P ratios over time was significantly higher in ears with fluctuating hearing (Mann-Whitney U = 39, p = 0.01) and MRI-designated endolymphatic hydrops (U = 27, p = 0.003). Linear regression demonstrated that an increasing vestibule E/P ratio correlated with worse hearing (Estimate = 45.31, SE = 7.88, p < 0.001). In addition, visit-to-visit increases in the E/P ratio correlated with shifts toward worse hearing thresholds (Estimate = 141.84, SE = 45.69, p = 0.003).
Why it matters
This study shows that volumetric MRI can track dynamic inner-ear fluid changes over time, linking quantified endolymphatic hydrops directly to hearing fluctuations as a potential objective monitoring biomarker.
Limits
The study is limited by a very small sample size (14 patients and 12 controls) and a single-center design. Specific etiologies within the hearing instability cohort and inter-rater reliability of the semi-automated pipeline were not detailed in the abstract.
Cited by
- context The total volume of inner ear fluid (perilymph and endolymph) is approximately 140 microliters, roughly equivalent to three raindrops.