Evaluation of the vestibular aqueduct in vestibulocochlear disorders by magnetic resonance imaging

The visibility of the vestibular aqueduct (VA) was examined using magnetic resonance imaging (MRI) in 95 patients: 15 patients with Meniere's disease, 4 with vestibular Meniere's disease, 4 with cochlear Meniere's disease and 72 patients with other vestibular and/or cochlear disorders. In order to v isualize the VA, the T-2-weighted image (T2WI) and the proton-density weigh ted image (PDWI) were obtained in the sagittal plane with a head coil. The visibility of the VA was classified into 4 grades, i.e. grade 0 (not visibl e), grade 1 (partially visible with PDWI), grade 2 (partially visible with T2WI) and grade 3 (clearly visible with T2WI). The visibility of the VA was significantly lower bilaterally in Meniere's disease, vestibular Meniere's disease, cochlear Meniere's disease and idiopathic bilateral sensorineural hearing loss (IBSNHL) than in the other diseases. The differences among Me niere's disease, vestibular Meniere's disease and cochlear Meniere's diseas e were not significant. The significance of decreased visibility in IBSNHL is unknown so far. The VA studies using MRI strongly suggest that the patho genesis of Meniere's disease, vestibular Meniere's disease, cochlear Menier e's disease and IBSNHL is, at least in part, related to the findings of the VA.