Normal modiolus: CT appearance in patients with a large vestibular aqueduct

• Published in: Radiology Vol. 204; no. 1; p. 213
• Main Authors: Lemmerling, M M, Mancuso, A A, Antonelli, P J, Kubilis, P S
• Format: Journal Article
• Language: English
• Published: United States 01-07-1997
• Subjects: Abnormalities, Multiple - diagnostic imaging; Adolescent; Adult; Case-Control Studies; Child; Child, Preschool; Cochlea - abnormalities; Cochlea - anatomy & histology; Female; Hearing Loss, Sensorineural - etiology; Humans; Male; Middle Aged; Observer Variation; Reference Values; Sensitivity and Specificity; Tomography, X-Ray Computed; Vestibular Aqueduct - abnormalities; Vestibular Aqueduct - anatomy & histology
• ISSN: 0033-8419
• DOI: 10.1148/radiology.204.1.9205250

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.
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.
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.
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.