Contrast perilymphatic MRI findings of inner ear in sudden hearing loss with vertigo

Abstract

Objective To explore the contrast perilymphatic MRI characteristics of inner ears with sudden hearing loss with vertigo. Methods Forty three patients with sudden hearing loss with vertigo and 35 patients with unilateral tinnitus diagnosed by the department of Otolaryngology-Head and Neck Surgery were retrospectively included. Forty eight ears (38 ears with unilateral sudden hearing loss and 10 ears in 5 cases with bilateral sudden hearing loss) were regarded as sudden hearing loss group, 35 asymptomatic ears (the opposite ears of the unilateral tinnitus ears) as control group. Thirty eight opposite ears of the 38 unilateral sudden hearing loss ears and 35 ears of the control group showed normal in the pure tone audiometry exam. One hundred and twenty one ears (48 hearing loss ears, 38 opposite ears of the 38 unilateral sudden hearing loss ears and the 35 control group's ears) underwent contrast perilymphatic MR exams, 0.4 to 0.5 ml gadolinium hydrate diluted with saline was injected through the tympanic membrane, twenty four hours later, three-dimensional fluid attenuated inversion recovery (3D-FLAIR) sequence was performed using a 3.0 T MRI scanner. After the contrast perilymphatic MR exam, success in the exam was judged through the raw image. The signal intensity ratio (SIR) of cochlea basal turn and homolateral brain stem was quantitatively calculated. The SIR difference of 48 ears with sudden hearing loss and 35 asymptomatic ears in control group was analyzed by t test. The SIR difference of the 38 unilateral sudden hearing loss ears and the contralateral asymptomatic ears was also analyzed. The presence of endolymphatic hydrops was judged. Results The contrast perilymphatic MRI of 121 inner ears with intratympanic gadolinium injection were all successful. Endolymphatic hydrops were observed in 12 sudden hearing loss ears with the occurrence rate of 25%(12/48). The SIR of basal turn and homolateral brain stem of the sudden hearing loss ears (2.062±0.907) were lower than the SIR of the control groups' asymptomatic ears (2.703± 0.640) with significant difference between them (t=3.619,P=0.001), the SIR of basal turn and homolateral brain stem of the unilateral sudden hearing loss ears (1.941±0.860) were also lower than the SIR of the contralateral asymptomatic ears (2.411±0.670) with statistical difference between them (t =3.270,P=0.002). Conclusions Endolymphatic hydrops were observed in sudden hearing loss with vertigo. The SIR of the cochlea in sudden hearing loss ears were lower than that of the asymptomatic ears, indicating the abnormal permeability of the round window membrane. Key words: Hearing loss; Sudden; Magnetic resonance imaging