Usefulness of Virtual Endoscopic Three-dimensional Reconstructions of the Middle Ear

Abstract

This work uses a new programme for producing 3D radiological images acquired by means of CT which enables the internal surfaces of the examined structures to be visualized. This new method, which is able to navigate inside organs in a similar way to fibreoptic endoscopy, is known as virtual endoscopy. CT examinations of the temporal bone were carried out using spiral equipment and endoscopic 3D processing was carried out on a separate workstation equipped with a volume-rendering programme. Once the technical parameters necessary for obtaining a representation of the internal surfaces had been defined, a simulation of a virtual otoscopy was conducted by moving the virtual endoscope from the external auditory canal through the annulus to the tympanic cavity. The simulation can be obtained either by moving the endoscope by hand, using the mouse, or by defining a path along which the software automatically creates an endoscopic 3D reconstruction. The images thus obtained are projected sequentially to give a "movie" effect, i.e. a continuous progression of the endoscope. The average time required to conduct the procedure ranges from 20 to 30 min. A virtual endoscopic visualization of the middle ear was obtained which, in particular, generated images of the tympanic cavity with the ossicular chain. In our experience, virtual otoscopy shows the anatomy of the structures of the tympanic cavity in excellent detail and may be considered complementary to CT, providing useful images enabling better visual representation and understanding of this complex structure. Although clinical applications of the technique remain to be defined it may have a role to play in presurgical diagnostic evaluation of the ossicular chain, epitympanum and retrotympanum.

3D image of the middle ear ossicles: three protocols of post-processing based on multislice computed tomography

“…Especially the Wrst three, widely used in the clinic, have been proved to be valuable, respectively [1][2][3][4][5][6][7][8][9][10][11]. However, there has been a dearth of literature on the comparison of the three protocols for the ossicles.…”

A Downloadable Three-Dimensional Virtual Model of the Visible Ear

“…Computer-based representation of 3-D anatomic data has become a useful tool for the study of the temporal bone and for surgical training as a result of recent developments in processing power of modern computers along with 3-D imaging and computer graphics technology. Several investigators have developed 3-D wireframe [1][2][3] or surface models of the human and animal inner ear using histological [4][5][6][7][8][9] , radiological [10,11] or microscopic images [12,13] . Although quite useful, many of these models contain a limited set of anatomical structures, which can be visualized as 2-D images or 3-D movies, but these models lack the capacity for user interaction.…”

Clinical application of virtual endoscopy as a support system for endoscopic sinus surgery

“…As a result, the production of VEIs became possible and was applied to tubular organs first [9Á11]. After that, it was also applied to the nasal cavity, paranasal sinuses [12Á15], and middle ear [7,16]. Moreover, the applicability of VEIs in determining surgical entrance points for simple mucoceles was demonstrated by a group of radiologists [17].…”