The Caroli test indicated mild vestibular weakness in two ears. Auditory brainstem responses revealed that all of the affected ears presented a variable degree of SNHL, ranging from moderate to profound ( 27). The two other cases were referred to our hospital for microtia and external auditory canal (EAC) atresia, and one of them had left facial palsy since birth. Ipsilateral hearing impairment since childhood was the main clinical presentation (n = 10) two of these patients also had tinnitus or vertigo. The age of the DIAC patients ranged from 4 months to 80 years (4 males and 8 females) ( Table 1). Among these patients, patient 11 had been previously reported ( 24). Among these, 12 patients (13 ears) were diagnosed with DIACs according to the following morphological criteria, based on HRCT images: 1) the IAC was divided into 2 or 3 canals by a complete or incomplete bony septum 2) the duplicated canals were connected to the FN canal or the vestibule and the cochlea. The ear HRCT images of 64813 SNHL patients diagnosed from August 2009 to November 2017 were retrieved from a picture archiving and communication system in our institution by an experienced otoradiologist. The purpose of this study was to summarize the imaging features of these ears on high-resolution CT (HRCT) and HRMRI. Therefore, we retrospectively analyzed the imaging data of 12 DIAC patients (13 ears) admitted to our institution over the past 8 years. A preoperative understanding of the accompanying temporal bone anomalies, such as outer, middle, and inner ear malformation and facial nerve (FN) canal migration, is considerably useful for otologists to be able to design appropriate operative approaches for DIAC patients who are suitable for ECI ( 26). Hence, preoperative accurate diagnosis of DIAC through computed tomography (CT) and magnetic resonance imaging (MRI) is necessary to facilitate selection of the appropriate treatment. In comparison, in DIAC, these nerves usually appear aplastic thus, most of the patients do not achieve marked benefits from ECI ( 20, 24). Vestibulocochlear nerves (VCNs) or cochlear nerves (CNs) in stenotic IACs are usually dysplastic as such, most of the patients can undergo and benefit from electronic cochlear implantation (ECI) ( 21, 25). DIAC is frequently misdiagnosed as IAC stenosis in clinical practice because of lack of knowledge about its imaging features ( 9, 13, 21). A duplicated internal auditory canal (DIAC) is a rare subtype of internal auditory canal (IAC) anomalies and is usually associated with ipsilateral congenital sensorineural hearing loss (SNHL).

Mri internal auditory canal