CLINICAL USEFULNESS OF THREE-DIMENSIONAL RECONSTRUCTION OF THE TEMPORAL BONE FROM CT SCANS

Abstract

Computed tomography (CT) is an important image processor for analysing temporal bone disease, but huge numbers of these two-dimensional images have required doctors to have a special ability of stereoscopic understanding. To solve this problem, we have tried to reconstruct temporal bone three-dimensionally from CT film using a personal computer and examining the possibilities of its clinical use.
Three cases of temporal bone CT films (otosclerosis, congenital cholesteatoma of pyramid and large mastoid cholesteatoma) were examined. Five structures of temporal bone (temporal bone contour, middle ear, mastoid, inner ear and cholesteatoma), which were chosen from enlarged black and white films originated from CT films, were inputted into the personal computer. The scale of each CT films were used as a standard point, for a decision of each image data X and Y points. Nexo, Z points were decided according to the width of each CT slices. Finally, all these date were combined into one image data using surface and shadow treatment, and expressed on the computer screen. All these processes of reconstruction were performed with commercial base software.
The results were satisfactory not only for understanding the stereoscopic positions of each structures in temporal bone, but also for analysing the degree of bone destruction by cholesteatoma. This system was especially useful for determining the best type of surgery in difficult cases, such as in pyramidal cholesteatoma. In conclusion, three-dimensional reconstruction will have a great role in diagnosis and treatment of temporal bone disease.