Cochlear hypoplasia is a group of inner ear malformations defined by a smaller than normal cochlea with various internal architectural abnormalities such as having <2 turns.


Cochlear hypoplasia accounts for 15% of cochlear malformations .

Radiographic features

According to the classification of Sennaroglu, there are four radiographically defined types of cochlear hypoplasia . In each type, the cochlea is a structure located at the end of the internal auditory canal, lucent on CT and fluid signal on MRI, that is overall smaller than normal.

  • CH-I: bud-like cochlea
    • round/ovoid and small cochlea, with absent modiolus and interscalar septa
  • CH-II: cystic hypoplastic cochlea
    • similar external shape to a normal cochlea but smaller, with defective modiolus and interscalar septa
  • CH-III: cochlea with <2 turns
    • similar external shape to a normal cochlea but shorter and fewer turns, with present but short modiolus and reduced total length of the interscalar septum
  • CH-IV: cochlea with hypoplastic middle and apical turns
    • normal basal turn but small middle and apical turns located more anterior and medial than normal

Additional extracochlear findings are variably associated:

Differential diagnosis

  • incomplete partition also features abnormal internal architecture of the cochlear and clear differentiation from the vestibule, but the cochlea has a normal-sized external contour
Siehe auch: