Flat-panel computed tomography versus multislice computed tomography to evaluate cochlear implant positioning

Abstract

ObjectiveTo evaluate and compare image quality between flat-panel volumetric computed tomography (fpVCT) and multislice CT (msCT) in temporal bones with cochlear implants (CIs), and to evaluate fpVCT imaging for accuracy in determining CI electrode positioning.MethodsSix cadaveric temporal bones were imaged prior to CI using fpVCT. Each bone was implanted with an electrode array and rescanned in order to create radial reformatted images through each electrode contact. Electrode–modiolar interval (EMI) distances were measured. The bones were fixed and cut in order to grossly evaluate for CI intrascalar positioning and insertional trauma.Main outcome measureTo compare image quality between fpVCT and msCT in temporal bones with CI, and to evaluate the utility of fpVCT in post-implantation temporal bone analysis.ResultsThe mean EMI distances did not differ significantly between fpVCT and msCT images, while the image quality was significantly better for fpVCT. Furthermore, information about intracochlear trauma and intrascalar electrode array positioning can be ascertained using this radiographic technique.ConclusionfpVCT and msCT do not differ significantly in the evaluation of EMI distances in implanted temporal bones, but the image quality is significantly better using fpVCT. Additionally, useful information regarding intracochlear trauma, electrode depth of insertion, and intrascalar positioning can be gained from fpVCT imaging. Given the ease of use, superior image quality, improved convenience, reduced levels of radiation, and agreement with histology, fpVCT is a valuable option for post-implantation temporal bone imaging.