[Imaging features of duplication of the internal auditory canal].

Objective: To explore multiple slices computed tomography (MSCT) and magnetic resonance imaging (MRI) features of duplication of the internal auditory canal (DIAC) in order to improve the accuracy of diagnosis.

Methods: Four cases (5 ears) were analyzed and the related documents were reviewed retrospectively. MSCT was performed on all cases, and two cases had MRI scanning at the same time.

Results: MSCT has shown that the internal auditory canal were divided into two canals by a bony septum in 5 ears. The superior canal ended in a very narrow connection to the facial canal, the inferior portion ended in connection to the cochlea and vestibule. The bony septums from the 2 ears were found no longer intact. The sum of diameter of the two canals was greater than 2 mm. In addition, 5 ears were found to have an enlarged vestibules and the hypoplasia lateral semicircular canals, and meanwhile, 2 ears of them were combined with ipsilateral microtia. Also 1 case of them was combined with microtia, outer acoustic atresia as well as abnormal middle ear. Multiplanar reconstruction and volume rendering images can entirely show the bony septum and two canals. In this study, the vestibular nerve, cochlear nerve and facial nerve were total hypoplastic in one ear, in the other ear, the vestibular and cochlear nerve were hypoplastic, and however, the facial nerve was intact.

Conclusions: MSCT can clearly depict duplication of the internal auditory canals and concomitant anomalies. MRI can clearly show the neural components and their associated malformation.