Cochlear incomplete partition type II
On CT, the cochlea is seen as having only 1 1/2 turns with coalescence of the apical and middle turn, forming a cystic apex 1.
Other findings include 1,2:
- absent interscalar septum
- absent osseous spiral lamina
- absent or deficient modiolus
- only normal at level of basal turn
- normal basal turn of the cochlea
- vestibular aqueduct enlargement very common
- can be normal, but rare
- normal vestibule
Care should be taken when interpreting MR in isolation for cochlear incomplete partition; it should always be correlated to petrous temporal bone CT-scan 3.
- T2: on thin sections, absence of interscalar septum and spiral lamina at the level of apical and middle turns may be seen 1
- 1. Joshi VM, Navlekar SK, Kishore GR, Reddy KJ, Kumar EC. CT and MR imaging of the inner ear and brain in children with congenital sensorineural hearing loss. Radiographics : a review publication of the Radiological Society of North America, Inc. 32 (3): 683-98. doi:10.1148/rg.323115073 - Pubmed
- 2. Yiin RS, Tang PH, Tan TY. Review of congenital inner ear abnormalities on CT temporal bone. The British journal of radiology. 84 (1005): 859-63. doi:10.1259/bjr/18998800 - Pubmed
- 3. Leung KJ, Quesnel AM, Juliano AF, Curtin HD. Correlation of CT, MR, and Histopathology in Incomplete Partition-II Cochlear Anomaly. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. 37 (5): 434-7. doi:10.1097/MAO.0000000000001027 - Pubmed