Objective To investigate the value of CT as preoperative and postoperative imaging technique for cochlear implant candidates.Methods Axial high-resolution temporal bone CT and three-dimensional reconstruction of inner ear were performed in 44 patients with sensorineural hearing loss. Cochlear view radiography was performed routinely in postoperation cases. CT scanning was performed in 3 postoperation cases.Results There were 1 case (2 ears) with Mondini malformation type Ⅰ, 2 case (4 ears)with Mondini malformation type Ⅱ in 32 patients with prespeech deafness. There were 2 case (4 ears) with chronic suppurative otitis meadia, 1 case (2 ears) with inner ear ossification,3 cases (6 ears)with large vestibular aqueduct syndrome,1 case (2 ear)with cochlear sclerosis in 12 patients with postspeech deafness. 1 case with intracochlear electrode knot and otitis meadia was found by CT.Conclusion CT plays an important role in selecting patients, observing implanted electrode and finding postoperative complication.

BACKGROUND:Artificial electronic cochlear (AEC) is a high-tech product used as a therapeutic substitute for pathological cochlear, and the implantative state of AEC can be assessed with the aid of imaging techniques.OBJECTIVE: To investigate the significance of CT and X-ray examination in the evaluation of preoperative selection and postoperative therapeutic result of patients with AEC implantation.DESIGN: Self-control observaton.SETTING:Auditory Rebuilding Ward of Otolaryngology Department, Zhujiang Hospital, Southern Medical University.PARTICIPANTS:Forty-four patients prepared for AEC implantation because of severe sensorineural hearing loss or extremely severer sensorineural hearing loss were recruited from the Otolaryngological Department, Zhujiang Hospital, Southern Medical University from January 1999 to June 2003.Thirty-two patients were with prespeech hearing loss, aged 2.5-12 and 12patients with postspeech hearing loss, aged 10-42.METHODS: Axial high-resolution temporal bone CT and three-dimensional reconstruction of inner ear were performed on 44 patients. They lay in supine position and received bilateral symmetric scanning with view of 9.6 cm. The baseline was set at the level of upper limit of auditory frame, and temporal bone was axially scanned. The scanning parameters were:thickness of 1 mm,spiral distance of 1.0 and interval of 0.5 mm; inserting rebuilding was performed after scanning with thickness of 1mm and interval of 0.1 mm. The improved routine cochlear axial stenves-X-ray image was performed after operation, and three patients underwent spiral CT temporal volume scanning due to suspicious postoperative complications.Postoperative inner ear and the arrangement and depth of implanted AEC.RESULTS: Totally 44 patients were remained in the result analysis perstructure: Of the 32 patients with prespeech deafness, 1 case (2 ears) was diagnosed as type Ⅰ Mondini malformation and 2 cases (4 ears) as type ⅡMondini malformation. Of the 12 patients with postspeech deafness, chronic suppurative otitis meadia was observed in 2 cases (4 ears ) , inner ear ossification in 1case (2 ears ), large vestibular aqueduct syndrome in 3 cases(6the arrangement and depth of implanted AEC :image of X-ray indicated that the electrode was implanted right in cochlea,displaying planar spiral shape and located at the bottom of inner-ear channel. Postoperative CT scanning was performed on 3 cases and revealed that electron was implanted into the bottom surroundings through round window and the electrode got twisted and infected in one cases.three-dimensional reconstruction of inner ear can be adopted before AEC implantation for screening out acute and chronic suppurative and severe ray image can afford clues to know the position and depth of implanted AEC and find out the twist and olithy of electrode, if any CT and cochlea image are supplemented for preoperative case selection and postoperative therapeutic evaluation, helping AEC to exert auditory function to the maximual degree.