Geometrical and Volume Changes of the Membranous Vestibular Labyrinth in Guinea Pigs with Endolymphatic Hydrops

Abstract

Objective: To evaluate geometrical and volume changes of membranous vestibular labyrinths in guinea pigs after endolymphatic hydrops (EH). Methods: The membranous labyrinths of normal guinea pigs and of those with EH for 4 and 8 weeks were reconstructed after being scanned using micro-computed tomography subseqent to being stained in osmium tetroxide (OsO₄). The diameters and volumes of the semicircular ducts, ampullae, utricles and saccules were measured based on the three-dimensional models. Results: The diameters of the ampullae and utricles of EH guinea pigs were greater than those of the normal guinea pigs, while there were no significant differences in the diameters of the semicircular ducts among all groups. The volumes of ampullae, utricles and saccules of the EH groups were greater than those of the control group, but there were no changes in volumes of semicircular ducts after EH. Conclusion: The dilations of the membranous vestibular labyrinth in guinea pigs with EH mainly occur at the ampullae, utricles and saccules.

The Correlation of a 2D Volume-Referencing Endolymphatic-Hydrops Grading System With Extra-Tympanic Electrocochleography in Patients With Definite Ménière's Disease

“…To mark the hydrops of each part of the inner ear, we defined the same expansile volume represent for 1 point in each part. Since three semicircular canals have five crura and three canals, we supposed each semicircular canal or crus had a similar volume according to the reported guinea pigs data (25) and human segmentation pictures showed by Inui et al (21). We also supposed ELH was distributed evenly in each part for easier calculation for the volume scores, and each part was marked as 1 point if the perilymph became narrow (mild hydrops) and 2 points if it became dark (severe hydrops).…”

Intratympanic Iodine Contrast Injection Diffuses Across the Round Window Membrane Allowing for Perilymphatic CT Volume Acquisition Imaging

“…The same group studied 3D cone beam CT MICS (membranous image between the vestibular cecum of the cochlea and saccule), showing the MICS patterns were significantly different than either healthy ears or non-affected ears in MD patients(3). Finally, Wu et al reconstructed the membranous labyrinths of normal and endolymphatic hydrops (EH) affected guinea pigs using micro-CT after staining with osmium tetroxide(12). They concluded volume and geometrical dilation changes occur mainly in the ampullae, utricles, and saccules of EH animals, without significant change in the semicircular canals.…”