Background: Although, the diagnostic criteria for enlarged vestibular aqueduct syndrome (EVAS) were determined by years. On the shoulders of predecessors, we still detected some new discoveries about EVAS by using 3D-real IR MRI.
Aims/objectives: To analyze the signal intensity of membranous and osseous labyrinths of vestibular aqueduct (VA) and endolymphatic sac (ES) in EVAS using three-dimensional real inversion recovery (3D-Real-IR) magnetic resonance imaging (MRI) after intratympanic injection of gadolinium.
Material and methods: The study is a prospective trial, diagnosed EVAS patients (n = 10) and none- patients (n = 10) were included. 3D-real-IR MRIs were performed to assess the endolymphatic hydrops (EH) and differentiated the endolymphatic and perilymphatic signal intensities of VA and ES.
Results: Compared to control group, EVAS group had VA osseous labyrinths middle diameter >1.5 mm different from membranous labyrinths. The cochlear EH was correlated with Mondini malformation and irrelation with the level of hearing loss (HL).
Conclusions and significance: Interspace of osseous labyrinths of VA and ES are much larger than their membranous labyrinths, which is not consistance with previous research. And cochlear Mondini malformation may cause endolymphatic fluid malabsorption, inducing cochlear EH. Osteal ampliative of VA and ES and cochlear EH, which are morphogenetic anomalies, may not the direct cause of HL in EVAS.
Keywords: Magnetic resonance imaging (MRI); endolymphatic hydrops (EH); endolymphatic sac (ES); intratympanic injection; vestibular aqueduct (VA).