MRI brain abnormalities in cochlear implant candidates: how common and how important are they?

Abstract

Objective: To investigate the incidence of abnormal findings on brain MRI in paediatric cochlear implantation candidates.

Methods: Retrospective review of brain MRI scans of cochlear implant patients between 2000 and 2009 who underwent MRI brain as part of their pre-operative work-up.

Results: MRI scans of 162 patients were reviewed (76 female patients and 86 male patients). The mean age at time of MRI scan was 3 years 8 months. Abnormalities were detected/ reported in 49 patients (30%). The total number of abnormalities detected was 51 (two patients had two separate abnormalities each). Of the abnormalities 82% could be related to known pre-existing conditions. 18% of the abnormalities were incidental/unexpected. Incidental/unexpected abnormalities were found in 9 patients (6%). Four of the patients with incidental abnormalities required referral and further investigations (2.5%). The most common abnormality detected was white matter changes (70%). All the white matter changes were related to pre-existing known medical conditions.

Conclusion: At our institution abnormalities detected by pre-operative brain MRI scans on cochlear implant candidates are common (30%). The majority of abnormalities are related to known pre-existing medical conditions. Incidental findings are rare (4%) and approximately half of them required further investigation or referral.