PT  - JOURNAL ARTICLE
AU  - K.J. Pippin
AU  - T.J. Muelleman
AU  - J. Hill
AU  - J. Leever
AU  - H. Staecker
AU  - L.N. Ledbetter
TI  - Prevalence of Internal Auditory Canal Diverticulum and Its Association with Hearing Loss and Otosclerosis
AID  - 10.3174/ajnr.A5399
DP  - 2017 Nov 01
TA  - American Journal of Neuroradiology
PG  - 2167--2171
VI  - 38
IP  - 11
4099  - http://www.ajnr.org/content/38/11/2167.short
4100  - http://www.ajnr.org/content/38/11/2167.full
SO  - Am. J. Neuroradiol.2017 Nov 01; 38
AB  - BACKGROUND AND PURPOSE: Focal low-attenuation outpouching or diverticulum at the anterolateral internal auditory canal is an uncommon finding on CT of the temporal bone. This finding has been described as cavitary otosclerosis in small case reports and histology series. The purpose of this study was to establish the prevalence of internal auditory canal diverticulum and its association with classic imaging findings of otosclerosis and/or hearing loss.MATERIALS AND METHODS: Temporal bone CT scans of 807 patients, obtained between January 2013 and January 2016, were retrospectively reviewed to identify internal auditory canal diverticula and/or classic imaging findings of otosclerosis. Clinical evaluations for hearing loss were reviewed for patients with internal auditory canal diverticula and/or otosclerosis.RESULTS: Internal auditory canal diverticula were found in 43 patients (5%); classic otosclerosis, in 39 patients (5%); and both findings, in 7 patients (1%). Most temporal bones with only findings of internal auditory canal diverticula (91%) demonstrated hearing loss, with 63% of this group demonstrating sensorineural hearing loss. The hearing loss classification distribution was significantly different (P < .01) from that in the classic otosclerosis group and in the group with both diverticula and otosclerosis.CONCLUSIONS: Internal auditory canal diverticula are not uncommon on CT examinations of the temporal bone and most commonly occur without classic imaging findings of otosclerosis. These lesions are associated with sensorineural hearing loss, and referral for hearing evaluation may be appropriate when present.CHLconductive hearing lossIACinternal auditory canalSNHLsensorineural hearing loss