The Application Of Spiral CT With Post Processing Techniques In Diagnosing Of Middle Ear Diseases

Objective: To explore the effect of spiral CT in displaying the normal structure and various pathological changes of middle ear, which giving objective proof in instituting the operative program and evaluating the curative effect after operation. Methods: Techniques of high resolution CT scan in the health and the patient group were performed, including overlapping reconstruction with small field of view, multi-planar reformation (MPR), curved reformation and volume reconstruction. Findings of 22 normal ears, 31 ears of chronic otitis media, 30 ears with congenital malformations of the external and middle ear, 4 ears with otospongiosis, 6 ears with trauma in temporal bone and 22 ears after operation on the middle ear were analyzed.Results: The chain of ossicles, facial canal, paries tympanicus, aditus ad antrum, eminentia papillaris, oval window and round window of normal ear were volumetric displayed in multi-angle and multi-plan view with spiral CT.Eardrum discontinuation was seen in 3 ears of merely chronic otitis media. The chain of ossicles were only partial destruction in 4 ears of caries type of chronic otitis media, while the shadow of soft tissue and destruction of ossicles were displayed in 11 ears of the same type. In 13 ears of cholesteatoma type of chronic otitis, tympanum enlargemen and the hardened border of destruction were discovered with partly or bulk erosion of ossicular chain.The structure of middle ear was normal in 4 ears of membrane imperforation in external auditory canal. The abnormality of stirrup and blockage of window in oval window and/or round window were more seen in 6 ears of purely middle ear deformity, while the anormaly of mallear and tympanum were more found in 20 ears of malformation of the external and middle ear. The absence of ossicular chain and the course abnormality of the canal for facial nerve were more in sclerotic mastoid while the mutation of canal for facial nerve was rarity in purely middle ear deformity.In 4 ears of otospongiosis, 3 ears were window type, 2 of which could seen the footplate thickening while another one ears without abnormality could been found. One ear was mixed type, blockage of round window and oval window and sponge kind change in cochlea could been manifested.