Middle Ear Imaging Using Virtual Endoscopy and Its Application in Patients with Ossicular Chain Anomaly

Abstract

Virtual endoscopy (VE) is a recently developed technique to provide a realistic surface rendering of various organs, which can be applied to the use of three-dimensional (3D) studies of several lesions. However, its advantages in otological disease have not been well investigated. In this study, we evaluated the application of VE in patients with ossicular chain anomalies. Virtual middle ear endoscopy was a time-saving method, however, we needed the appropriate technical procedures of algorithm and reconstruction spacing to generate accurate 3D images of ossicles. We obtained virtual surgical views of middle ear structures and related anomalies, and confirmed by intraoperative findings that these images were mostly compatible with the actual lesions of ossicles. VE allowed an identification of the anatomy of the ossicles and adjacent structures simultaneously. The elements of the stapedial crura were clearly visualized with VE images in 93.3% of normal ears. Pathological ossicular chain findings such as malleus or incus fixation, dislocation and disruption, except footplate fixation were investigated successfully. One possible procedure, using alterable CT value in the obtained VE images on the monitor, is proposed for further detection of fine lesions of the ossicles. These observations suggest that virtual middle ear simulations accurately represent major intraoperative findings. This technique may have an important role in preoperative planning, surgical training, and/or postoperative evaluation in otology.

Evaluation of genial tubercle anatomy using cone beam computed tomography

“…), it is still difficult to analyze complex anatomy on the basis of CT imaging alone (28,29). CT has been of great value for evaluation of anatomical structures, but despite the fact it can yield very thin adjacent slices, it is not yet a perfect technique.…”

Is there a role for virtual otoscopy in the preoperative assessment of the ossicular chain in chronic suppurative otitis media? Comparison of HRCT and virtual otoscopy with surgical findings

“…Rodt et al attempted to standardize the post processing technique for virtual endoscopy of the middle ear by applying fixed threshold of −500 and −250 HU for each ear [4]. While studying normal aerated ears, Himi et al realized that though the visualization of most of the ossicular chain was excellent on the virtual otoscopy; in 6.7% cases the delineation of the stapedial crura and the intercrural space was not possible [6]. In later studies, many limitations of the virtual otoscopy with regards to the assessment of the ossicular chain were found [7][8][9][10][11].…”

“…In comparison with most of the previous studies [1,2,4,6,[14][15][16] where virtual otoscopy was done in well-aerated ears with high inherent contrast between the density of the air and the ossicles, we attempted this imaging technique in cases of CSOM where the ossicular chain is buried in the mass of cholesteatoma. The technique was quite difficult and it was based only on the subtle difference between the density of the ossicles and that of the surrounding cholesteatoma.…”

Malformations of the Temporal Bone. Diagnosis and Classification

“…Für die Analyse der Ossikel sind neben den primären Schnittbildern auch sekundäre dreidimensionale Rekonstruktionen wie z.B. in Form der virtuellen Endoskopie hilfreich [18,27,45]. Aus der Computertomographie kann jedoch keine sichere Aussage zur Funktion der Kette getroffen werden.…”