Objectives
The purpose of this study was to determine the normal volume ranges of cochlear duct, saccule, and utricle, and to assess endolymphatic hydrops in Ménière disease.
Study Design
Retrospective temporal bone study.
Methods
Three-dimensional (3-D) images of membranous labyrinth were reconstructed from 31 normal temporal bones, six temporal bones from three patients with bilateral Ménière disease, and 16 temporal bones from eight patients with unilateral Ménière disease. Volumes of each part of membranous labyrinth were measured in each temporal bone group after 3-D reconstruction.
Results
The mean volumes and upper normal volume limits (over the 95% confidence interval) of the cochlear duct, saccule, and utricle were 7.67 and 9.77 mm3, 2.42 and 3.68 mm3, and 10.65 and 16.45 mm3, respectively. All three patients with bilateral Ménière disease showed endolymphatic hydrops (excess of volume over normal limits) in both ears. Of eight patients with unilateral Ménière disease, five had no symptom in the contralateral ear, whereas three patients had histories of progression from uni-lateral to bilateral Ménière disease 13–21 years after the initial onset. All of the diseased and three of eight contralateral ears showed endolymphatic hydrops. In contrast, no hydrops was observed in any part of the membranous labyrinth in asymptomatic ears.
Conclusions
Our findings suggest that cochleosaccular hydrops is a sensitive finding in Ménière disease. In addition, the volume data obtained from this study could be useful as a standard value for the assessment of hydrops in diagnostic imaging of the inner ear in Ménière disease.
The stria vascularis may be ischemic bilaterally both in bilateral and unilateral Ménière's disease. Abnormal findings in the contralateral ears in unilateral Ménière's disease reported in previous studies might be related to poor vascularity of the stria vascularis.
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