コーガン症候群―MRIで内耳に変化を認めた一例―

抄録

Cogan's syndrome is primarily diagnosed based on subsequent episodes of an inflammatory eye disease and rapidly progressive, usually sequential bilateral loss of audiovestibular function. Since there are still no specific tests for the syndrome, it is difficult to diagnose Cogan's syndrome in the early stage before the emergence of both eye and audiovestiubular symptoms. We present a case of a 34-year-old woman who complained of vertigo and bilateral hearing loss. Magnetic resonance imaging (MRI) of the inner ear was performed before the emergence of keratitis. MRI on the 23rd day after onset of hearing loss revealed a slightly high intensity on TI-weighted images in the right vestibule, which showed profound hearing loss. On the 54th day after onset, high signal intensity was noted in the right cochlea, the vestibule, and lateral semicircular canal on Tl-weighted images, but no enhancement. The high signal intensity disappeared seven months after onset, but there was no defect of inner ear signs on the T2-weighted images. A high signal of the inner ear on T1-weighted images is not a specific sign of MRI in Cogan's syndrome, since it is sometimes encountered in the inner ear of labyrinthitis, bleeding in patients with leukemia, and intralabyrinthine schwanoma. However, MRI could be a possible method for the early diagnosis of Cogan's syndrome because this finding might be recognized before the onset of eye symptoms.