Fig. 4

Type 4 JB in a hydropic ear. Type 4 was demonstrated in the (a) Pöschl and (b) sagittal planes with the JB well above the inferior margin of the PSCC, as well as the inferior margin of the IAC, which was imaged at the fundus with the modiolus. The external aperture of the VA was not visualized in the Pöschl plane (a) and sagittal plane (b), where an upward extension of the bulb invaded the region of the VA. c and d Three-dimensional reconstruction computed tomography showing the type III anatomic relationship between JB and VA, where VA obliteration (white arrow) was observed on the posterosuperior view (c) and an upward JB encroachment upon the VA resulting in VA obstruction (white arrow) was observed on the posteroinferior view (d). 3D-real IR MRI showed an extremely large EH in the vestibule (red arrow) with significant cochlear hydrops (white arrow) before surgery (e). Postoperative image showed the cochlear and vestibular hydrops disappeared, where normal bright perilymphatic fluid was visible in both cochlea (white arrow) and vestibule (red arrow) (f). CC, common crus; JB, jugular bulb; IAC, internal auditory canal; PSCC, posterior semicircular canal; VA, vestibular aqueduct; SSCC, superior semicircular canal; 3D-real IR, three-dimensional real inversion recovery