Postmeningitic labyrinthine ossification primarily affecting the semicircular canals

In a series of six cochlear-implant candidates, including three small children, labyrinthine ossification in various stages of development was observed at CT. In four of the candidates the ossifying process was more advanced in the semicircular canals than in the cochleae, and in two equally distributed. The ossifying process developed during a period of 4–5 months in two of the children. Asymmetry of its extension was found in four patients. The causative organisms were Hemophilus influenzae and Streptococcus pneumoniae. The radiologic assessment of cochlear-implant candidates should include the semicircular canals where the ossification may start, and herald the development of cochlear ossification. Received 9 November 1995; Revision received 17 April 1996; Accepted 25 April 1996