Radiation dose reduction in postoperative computed position control of cochlear implant electrodes in lambs - An experimental study

Weisstanner, Christian; Mantokoudis, Georgios; Huth, Markus; Verma, Rajeev Kumar; Nauer, Claude; Senn, Pascal; Caversaccio, Marco; Wagner, Franca (2015). Radiation dose reduction in postoperative computed position control of cochlear implant electrodes in lambs - An experimental study. International journal of pediatric otorhinolaryngology, 79(12), pp. 2348-2354. Elsevier 10.1016/j.ijporl.2015.10.040

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Cochlear implants (CI) are standard treatment for prelingually deafened children and postlingually deafened adults. Computed tomography (CT) is the standard method for postoperative imaging of the electrode position. CT scans accurately reflect electrode depth and position, which is essential prior to use. However, routine CT examinations expose patients to radiation, which is especially problematic in children. We examined whether new CT protocols could reduce radiation doses while preserving diagnostic accuracy.


To investigate whether electrode position can be assessed by low-dose CT protocols, a cadaveric lamb model was used because the inner ear morphology is similar to humans. The scans were performed at various volumetric CT dose-indexes CTDIvol)/kV combinations. For each constant CTDIvol the tube voltage was varied (i.e., 80, 100, 120 and 140kV). This procedure was repeated at different CTDIvol values (21mGy, 11mGy, 5.5mGy, 2.8mGy and 1.8mGy). To keep the CTDIvol constant at different tube voltages, the tube current values were adjusted. Independent evaluations of the images were performed by two experienced and blinded neuroradiologists. The criteria diagnostic usefulness, image quality and artifacts (scaled 1-4) were assessed in 14 cochlear-implanted cadaveric lamb heads with variable tube voltages.


Results showed that the standard CT dose could be substantially reduced without sacrificing diagnostic accuracy of electrode position. The assessment of the CI electrode position was feasible in almost all cases up to a CTDIvol of 2-3mGy. The number of artifacts did not increase for images within this dose range as compared to higher dosages. The extent of the artifacts caused by the implanted metal-containing CI electrode does not depend on the radiation dose and is not perceptibly influenced by changes in the tube voltage. Summarizing the evaluation of the CI electrode position is possible even at a very low radiation dose.


CT imaging of the temporal bone for postoperative electrode position control of the CI is possible with a very low and significantly radiation dose. The tube current-time product and voltage can be reduced by 50% without increasing artifacts. Low-dose postoperative CT scans are sufficient for localizing the CI electrode.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Ear, Nose and Throat Disorders (ENT)
10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research > ARTORG Center - Hearing Research Laboratory
04 Faculty of Medicine > Department of Radiology, Neuroradiology and Nuclear Medicine (DRNN) > Institute of Diagnostic and Interventional Neuroradiology

UniBE Contributor:

Weisstanner, Christian, Mantokoudis, Georgios, Huth, Markus, Verma, Rajeev Kumar, Nauer, Claude, Senn, Pascal, Caversaccio, Marco, Wagner, Franca


600 Technology > 610 Medicine & health








Martin Zbinden

Date Deposited:

14 Jan 2016 08:19

Last Modified:

05 Dec 2022 14:51

Publisher DOI:


PubMed ID:


Uncontrolled Keywords:

Animal model; Cochlea implantation; CT; Radiation dose reduction; Children





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