Perilymphatic Fistula and Autoimmune Labyrinthitis

PURPOSE: To relate the finding of selecti ve enhancement of different turns of the cochlea to the frequency range of the hearing loss measured by audiogram . METHODS: Six patients aged 23 to 53 years, four men and two women, who presented w ith sudden hearing loss and had segmental enhancement of different turns of the cochlea on contrast-enhanced MR imaging were included in this retrospective study . The patients were imaged on a 1.5 T MR imaging system using preand postcontrast axial T 1-weighted images and postcontrast coronal T ] -weighted images through the temporal bone. RESULTS: The basal turn of the cochlea enhanced selectively in f ive of the six patients and the apical turn enhanced in the sixth patient. All patients had sensorineural hearing loss. Three of the patients with basal turn enhancement had predom inantly high-frequency hearing loss, whereas the patient with apical turn enhancement had predominantly low-frequency hearing loss. The two other patients with basal turn enhancement had com plete hearing loss. Three patients had presumed auto im mune labyrinthitis. The other three patients had strong clinical and surgical evidence of a perilymphatic fi stula . CONCLUSION: Contrast-enhanced MR imaging may demonstrate selective enhancement of different turns of the cochlea. In certain patients, the areas of enhancem ent may correlate with specific hearing loss in the frequencies mapped by the enhancing segment. Enhancement of the cochlea may represent radiologic evidence of cochlear inflammation secondary to a peril ymphatic fi stula.