The main findings on CT are:
Absence of these structures gives a cystic appearance to the cochlea. However, IP-I is a spectrum that varies from mild to severe, with variable cochlear external contour and variable associated abnormality of the vestibule and semicircular canal.
In the mildest form, abnormalities are isolated to the cochlea, with lack of modiolus and interscalar septum.
In-between the mild and the severe form lies a spectrum of associated vestibular and semicircular canal dilatation.
In the severe form (also known as cystic cochleovestibular malformation), the cochlea is featureless, and both the cochlea and vestibule are cystic. This appearance has been likened to a figure 8 morphology.
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