Congenital malformations of the inner ear and the vestibulocochlear nerve in children with sensorineural hearing loss: evaluation with CT and MRI.
OBJECTIVE
The purpose of this work was to study the diagnostic value of CT and MRI in children with sensorineural hearing loss and to analyze anatomic abnormalities of the inner ear and the vestibulocochlear nerve in this patient group.


METHODS
We evaluated 42 inner ears in 21 children with congenital deafness who had congenital inner ear malformations and who were candidates for cochlear implants. All patients were studied with high resolution MR and helical CT examinations. The MR study included a T2-weighted 3D fast SE sequence. We describe and tabulate the anatomic abnormalities. Special attention was given to abnormalities of the vestibulocochlear nerve. The field of view in the plane according to the length axis of the internal auditory canal (IAC) was 4 cm. Additional continuous parasagittal reformations perpendicular to the length axis of the IAC were studied with a field of view of 3 cm.


RESULTS
CT and MRI allowed accurate identification of malformations of the inner ear in children with congenital deafness. We identified 99 malformations, with a majority of patients demonstrating multiple abnormalities. Common imaging findings were Mondini abnormality and Mondini variants (12/42) and fusion of the lateral or superior semicircular canal with the vestibule (12/42). MRI demonstrated in 9 of 21 patients a rudimentary or absent vestibulocochlear nerve in the auditory canal.


CONCLUSIONS
CT and MRI are important modalities to analyze the inner ear in children who are candidates for cochlear implants. MRI with an extremely small field of view should be used to study possible abnormalities of the vestibulocochlear nerves. This may alter clinical care and allow cochlear implant placement in patients whose electrodiagnostic studies suggest that the implant should not be performed. The detailed analysis of abnormalities of the inner ear might establish prognostic factors.
Westerhof
J P
JP
Department of Radiology, Elkerliek Ziekenhuis, The Netherlands. jwesterhof@elkerliek.nl
Rademaker
J
J
Weber
B P
BP
Becker
H
H
D002648:Child; D002675:Child, Preschool; D003054:Cochlear Implants; D007758:Ear, Inner / Q000002:abnormalities*; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D018579:Patient Selection; D011379:Prognosis; D014057:Tomography, X-Ray Computed; D000159:Vestibulocochlear Nerve / Q000002:abnormalities*