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Cone Beam Computed Tomography, A Low-Dose Imaging Technique in the Postoperative Assessment of Cochlear Implantation

Ruivo, Joana*; Mermuys, Koen; Bacher, Klaus; Kuhweide, Rudolf§; Offeciers, Erwin; Casselman, Jan W.

doi: 10.1097/MAO.0b013e31819679f9
Cochlear Implants

Background: Cone beam computed tomography (CBCT) has become an extremely useful technique for dentomaxillofacial imaging because it provides clear images of highly contrasted structures. Previous studies evaluating the applicability of this technique in otologic imaging were very encouraging but were only performed in vitro on temporal bone specimens. The intracochlear positioning of the individual electrodes after cochlear implantation by means of CBCT has not yet been shown in vivo.

Objective: We describe a protocol for in vivo postoperative imaging of cochlear implants by CBCT. Moreover, the effective dose was measured and compared with the effective dose used on 4- and 16-slice multislice computed tomography (MSCT) by using a RANDO-phantom.

Main Outcome Measure: Developing a protocol for in vivo postoperative imaging of cochlear implants by CBCT.

Results: CBCT provides high-resolution and almost artifact-free multiplanar reconstruction images allowing assessment of the precise intracochlear position of the electrode and visualization of each of the individual contacts. The calculated effective dose of the used CBCT and MSCT acquisitions is 80 μsv for the CBCT, 3,600 μsv for the 16-slice computed tomography, and 4,800 μsv for the 4-slice computed tomography.

Conclusion: These preliminary results suggests that, for in vivo postoperative evaluation of cochlear implants, CBCT can provide at least the same information as conventional radiography, digital radiograph, and MSCT but in a more comfortable and a much more safer way.

*Serviço de Imagiologia Neurológica, Hospital de Santa Maria, Lisbon, Portugal; †Department of Radiology, A.Z. St.-Jan Hospital, Bruges; ‡Department of Medical Physics and Radiation Protection, Ghent University, Gent; §Department of Otorhinolaryngology, A.Z. St.-Jan Hospital, Bruges; and ∥University Department of Otolaryngology, St.-Augustinus Hospital, Antwerp, Belgium

Address correspondence and reprint requests to Jan W. Casselman, M.D., Ph.D., Department of Radiology, A.Z. St.-Jan Hospital, Ruddershove 10, 8000 Bruges, Belgium; E-mail:

These authors (J. R. and K. M.) equally contributed to this study.

© 2009 Otology & Neurotology, Inc.