Malformations and abnormalities of the petrous portion of the temporal bone

High-resolution computed tomography (HRCT) is the procedure of choice in the diagnostics of abnormalities of the middle and inner ear. It allows a detailed presentation of anatomical features and achieves the prerequisites for selection of the various therapeutic options. The highly diverse abnormalities can be described using detailed imaging analyses. Malformations with an abnormally developed modiolus are assumed to be early embryological defects, such as the classical Mondini dysplasia. The essential therapeutic option for middle ear deformities is still a cochlear implant. The domain of magnetic resonance imaging (MRI) is not only in the analysis of the cochlear nerve and for exclusion of fibrosis or ossification of the labyrinth but is also able to visualize details of isolated malformations, such as an extended vestibular aqueduct or subtle alterations to the vestibule or can visualize them better in comparison to CT. Radiological diagnostics are used not only for classification but also to recognize typical clinical problem situations and play a key role in the diagnostics of hearing disorders and selection of the optimal therapeutic procedure. (orig.)