Evaluation of the vestibular aqueduct in Ménière's disease using multiplanar reconstruction images of CT

Abstract

Previous studies, in which the vestibular aqueduct (VA) was determined using axial CT, have indicated that the VA sizes in patients with Ménière's disease were smaller than those in the subjects of the control group and that 25-35% of ears with Ménière's disease were "non-visible type." In this study, in addition to obtaining the axial size, we measured the VA size along the vertical plane by using vertical multiplanar reconstruction (MPR) images. The VA size of both ears of patients with unilateral Ménière's disease (n=34) and of subjects of the control group (n=30) was measured by using the vertical MPR and the axial CT images. The VA size was measured along the axial and vertical planes in all subjects. The parameters measured on the axial image of the VA correlated with each other; however, the parameters on the vertical MPR image did not correlate with those on the axial image. Values of parameters in the affected and nonaffected ears with Ménière's disease tended to be smaller than those in the control ear. The external aperture areas of the VA fenestra of the affected and nonaffected ears of patients with Ménière's disease were significantly smaller than that for the control ears. Our findings suggest that the vertical parameters of the VA yield information that is independent of that provided by the axial parameters. In both ears of patients with unilateral Ménière's disease, the VA tended to be thinner than those in the control ear.