Abstract
PurposeTo estimate the prevalence of endolymphatic sac hypoplasia (EShp)-a proposed specific finding in Ménière's disease (MD) that defines an endophenotype characterized by bilateral involvement, male predominance, temporal bone abnormalities, and familial clustering-in individuals without MD, to assess its specificity for the condition.MethodsWe analyzed 956 temporal bone CT scans from individuals without MD to assess the prevalence of EShp using the Angular Trajectory of the Vestibular Aqueduct (ATVA) marker. ATVA distribution, reproducibility, and associations with clinical variables were also evaluated.ResultsEShp was identified in 6 ears from 4 individuals, yielding a prevalence of 0.6% per patient and 0.8% per ear. ATVA values had a median of 95.0° (IQR = 12.5°, range 65.9°-159.4°). Interobserver agreement was good (ICC = 0.75), with a mean bias of 6.2° ± 5.4° and 5.5% of ears outside the 95% limits of agreement. No significant associations were found between ATVA and sex, age, or clinical diagnosis.ConclusionsEShp is rare in individuals without MD, supporting its specificity and potential role in MD pathophysiology. The ATVA marker is reliable and reproducible and may serve as a CT biomarker for the hypoplastic MD endophenotype.