Normal modiolus: CT appearance in patients with a large vestibular aqueduct.
OBJECTIVE
To determine the computed tomographic (CT) appearance of the normal modiolus and the pathologic alteration in patients with a large vestibular aqueduct and an otherwise normal-appearing cochlea.


METHODS
Temporal bone CT studies obtained before and after a major upgrade of CT capability in 1992 were reviewed in four groups: Group A (1.5-mm section thickness) comprised 50 normal ears in 43 patients, group B (1-mm section thickness) comprised 75 normal ears in 50 patients, group C (1.5-mm section thickness) comprised 16 ears with a large vestibular aqueduct in 10 patients, and group D (1-mm section thickness) comprised 23 ears with a large vestibular aqueduct in 12 patients. All groups comprised adult and pediatric patients.


RESULTS
In groups A and B, the normal modiolus was visualized in 90% and 100% of ears, respectively. In groups C and D, with a total of 39 ears with a large vestibular aqueduct and an otherwise normal cochlea, modiolar deficiency was demonstrated in 100% of ears.


CONCLUSIONS
CT is an excellent technique for depicting the cochlear modiolus. Results suggest that all ears with a large vestibular aqueduct have associated cochlear modiolar deficiencies. Thus, a large vestibular aqueduct may be only occasionally, if ever, an isolated developmental anomaly of the inner ear.
Lemmerling
M M
MM
Department of Radiology, University of Florida College of Medicine, Gainesville 32610, USA.
Mancuso
A A
AA
Antonelli
P J
PJ
Kubilis
P S
PS
D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003051:Cochlea / Q000002:abnormalities* / Q000033:anatomy & histology; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012016:Reference Values; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014723:Vestibular Aqueduct / Q000002:abnormalities* / Q000033:anatomy & histology