Computed tomography and otosclerosis: a practical method to correlate the sites affected to hearing loss.
OBJECTIVE
We present a practical method for correlating computed tomography (CT) scans with hearing loss in otosclerosis.


METHODS
We reviewed the CT scans of 18 patients (34 ears) with clinical otosclerosis who were seen between 2007 and 2008. The scans were reviewed by an otologist in a clinical office setting, followed by a blinded radiologist working at an imaging workstation. The 5 most commonly affected sites in otosclerosis were evaluated for evidence of otospongiosis and then correlated with the degree of air-bone gap and sensorineural hearing loss.


RESULTS
Positive CT findings were noted in 70.5% of ears, with a 94% concordance between readings. The sites affected included the ante fenestram (21 ears), round window niche (12), cochlear promontory (4), cochlear apex (3), and posterior fenestram (2). The average air-bone gap increased with each additional site of involvement within an otic capsule (p = 0.004). The bone conduction threshold also increased, on average, with each additional affected site (p = 0.047).


CONCLUSIONS
Most patients with clinical evidence of otosclerosis have evidence of otosclerosis on CT that is readily detected in the office setting. Ears with more affected sites have a significantly greater degree of air-bone gap and sensorineural hearing loss.
Department of Otolaryngology-Head and Neck Surgery, Georgetown University, Washington, DC 20007, USA.
Benjamin J
BJ
Wycherly
Frank
F
Berkowitz
Anne-Michelle
AM
Noone
H Jeffrey
HJ
Kim
D000328:Adult; D001301:Audiometry, Pure-Tone; D007758:Ear, Inner / Q000000981:diagnostic imaging*; D005260:Female; D006314:Hearing Loss, Conductive / Q000175:diagnosis / Q000209:etiology; D046089:Hearing Loss, Mixed Conductive-Sensorineural / Q000175:diagnosis / Q000209:etiology; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010040:Otosclerosis / Q000150:complications / Q000000981:diagnostic imaging*; D013701:Temporal Bone / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D055815:Young Adult