Three-dimensional imaging of active and passive middle ear prostheses using multislice computed tomography.

Objective: This study examined the explanatory power of 3-dimensional visualization of middle ear prostheses and to introduce this method as a supplementary diagnostic tool.
Methods: Various prostheses were examined in vitro. Surface rendering and perspective volume-rendering techniques were compared with axial, curviplanar, and maximum intensity projection images. One hundred three patients with hearing difficulty underwent high-resolution computed tomography scanning. The 3-dimensional images of 41 patients after nonspecific middle ear surgery were compared with the tympanoscopic findings.
Results: The PVR technique allowed the depiction of the smallest individual substructures of the prostheses. The evaluation of the prostheses' localization using PVR was significantly better than using maximum intensity projection (P < 0.001). Surface rendering showed no advantages over 2-dimensional imaging. Diagnostic findings of high-resolution computed tomography were comparable to tympanoscopy (specificity 100%, sensitivity 95.1%).
Conclusion: The 3D depiction facilitates the evaluation of middle ear prostheses fitting.