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 .
Other findings include :
- 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 .
- T2: on thin sections, absence of interscalar septum and spiral lamina at the level of apical and middle turns may be seen