[CT and MRI diagnosis of congenital stenosis of the internal auditory canal].

OBJECTIVE: To investigate multiple slice computed tomography (MSCT) and magnetic resonance imaging (MRI) features of congenital stenosis of the internal auditory canal (CSIAC) and improve the ability for diagnosis. METHOD: Thirteen cases with fifteen ears were studied. In all cases a MSCT and MRI was performed. RESULTS: Eleven cases were unilateral, and 2 cases were bilateral. MSCT could show the narrowness of IAC. Three cases were isolated, but the others were combined with inner ear malformations. One ear had inner, middle and outer ear malformations. One ear had inner, middle, and outer ear malformations with a frontal bone malformation. MRI demonstrated that all of the vestibulocochlear nerves were hypoplastic. The cochlear nerve in seven ears was not present, in seven ears the nerve was thinner, and in the last case it was poorly visualized. The facial nerve in two ears was hypoplastic. Volume rendering (VR) could present the degree of the narrowed internal auditory canals, combined with other inner ear anomalies. CONCLUSION: MSCT will show the degree of the narrow internal auditory canals and combined anomalies, while the MRI can further demonstrate the nerves' development.