Article Figures & Data
Figures
- Fig 1.
Labyrinthine aplasia. Axial (A) and coronal (B) right temporal bone CT images demonstrate the complete absence of normal inner ear structures. Notice the diminished size of the inner ear edifice and absence of a well-formed internal auditory canal, which help to distinguish this from labyrinthitis ossificans.
- Fig 2.
IP-II. Axial CT (A) and CISS (B) images through the right temporal bone demonstrate cochlear dysplasia with a deficient modiolus and fusion of the middle and apical turns, resulting in a bulbous-appearing cochlear apex. The vestibule and semicircular canals are normal, and the vestibular aqueduct is not enlarged.
- Fig 3.
Cochlear aplasia. Axial CT image through the right temporal bone demonstrates a dysplastic vestibule fused to an abnormal lateral SCC, with absence of the cochlea. Notice the small canal for the vestibular nerve (arrow).
- Fig 4.
Common cavity deformity. Axial CT (A) and CISS (B) images through the left inner ear demonstrate an enlarged cystic cavity representing the cochlea and vestibule without differentiation.
- Fig 5.
Cystic cochleovestibular anomaly (IP-I). Axial CT (A) and CISS (B) images through the right temporal bone demonstrate a cystic-appearing and featureless cochlea and vestibule. The cochlea and vestibule form a “figure 8” or “snowman” contour, with slightly increased separation compared with the common cavity deformity demonstrated in Fig 4.
- Fig 6.
Cochlear hypoplasia. Axial CT (A) and FSE T2-weighted (B) images through the left temporal bone demonstrate a small cochlea, resembling a bud off of the IAC. The vestibule is also enlarged and dysplastic and is fused with a pocketlike lateral SCC.
- Fig 7.
Enlarged vestibular aqueduct. A, Axial CT image through the right temporal bone demonstrates enlargement of the vestibular aqueduct, which has a fanlike configuration (arrow). Notice how the width of the aqueduct at its midpoint is larger than that of the adjacent SCCs. The cochlea is also mildly dysplastic (IP-II). B, Axial CISS image through the left temporal bone in a different patient demonstrates marked enlargement of the endolymphatic duct and sac (asterisk).
- Fig 8.
Lateral SCC dysplasia. Axial (A) and coronal (B) right temporal bone images demonstrate a dysplastic pocketlike lateral SCC, which is fused to the vestibule and missing its central bony island. On the coronal image, the lateral SCC is truncated. Both the superior and posterior SCCs are present.
- Fig 9.
SCC dysplasia with a small lateral SCC bony island. The transverse diameter of the lateral SCC (double arrow) only measures 1.9 mm (normal, 2.6–4.8 mm). The vestibule is also enlarged and dysplastic, and the cochlea is hypoplastic.
- Fig 10.
Cochlear nerve deficiency. A, Reconstructed sagittal CISS image through the right IAC demonstrates the absence of the right cochlear nerve. B, Compare with the sagittal image through the normal left IAC.
- Fig 11.
Bony cochlear nerve canal atresia in a patient with CND. A, Axial CT image through the right temporal bone of the same patient shown in Fig 10 demonstrates an atretic canal for the cochlear nerve at the base of the cochlea. B, Compare A with the normal-caliber BCNC on the left.
Tables
Spectrum of congenital inner ear malformations as proposed by Sennaroglu and Saatci13
Time of Insult (week) Malformation Features Third Labyrinthine aplasia (Michel deformity) Complete absence of cochlea and vestibule Third-to-fourth Cochlear aplasia Complete absence of cochlea; vestibule present Fourth Common cavity Single cystic cavity representing cochlea and vestibule, without any differentiation Fifth Cystic cochleovestibular anomaly (IP-I) Cystic-appearing cochlea lacking entire modiolus and cribriform area; large cystic vestibule Sixth Cochlear hypoplasia Cochlea and vestibule are separate but are smaller than normal; hypoplastic cochlea resembles small bud off the IAC Seventh Incomplete partition type II (IP-II) Cochlea consists of 1.5 turns, in which middle and apical turns coalesce to form a cystic apex; vestibule and VA may be enlarged
