人工耳蜗植入术后植入电极的影像学检查

目的 探讨建立螺旋CT扫描及三维重建技术观察人工耳蜗植入电极方法，并比较X线摄片方法与螺旋CT扫描三维重建方法的耳蜗内电极的影像学特征及其临床应用价值。方法 18例人工耳蜗植入患者全部作术后X线摄片检查。其中9例用经眼眶前后位摄片，9例采用侧斜位60。摄片。3例患者施行术后螺旋CT扫描及内耳三维重建方法。结果 2种投射头位的X线摄片均可显示电极形态及单个电极对，可间接判断电极在耳蜗内的植入深度。螺旋CT扫描三维重建图可直观地显示耳蜗形态、电极形态及其在耳蜗内植入的深度，可清晰识别单个电极对。结论 螺旋CT扫描三维重建方法可直观观察植入电极的形态及位置，可准确判断电极在耳蜗内植入的深度，有其独特的临床应用价值。

Image examination of postoperative evaluation for the cochlear implanted electrode]

OBJECTIVE: To evaluate the image feature of the X-ray plain film, the spiral computed tomography (CT) scans and three dimension reconstruction of inner ear with implanted electrode. METHODS: Eighteen patients of cochlear implant (MEDEL Combi 40+) recipients were involved in this study. The implanted electrode of all patients were examined on the fifth to seventh postoperative day, by the use of X-ray plain film with either anteroposterior transorbital projection (nine cases) or lateral position with coronal 60 degrees away from the examine table (nine cases). Three of the cochlear implant recipients were examined by the way of spiral CT scans with axial 1 mm image slices. The data of the CT scans was transferred to workstation for three-dimensioned reconstruction (direct volume rendering) of the inner ear. RESULTS: The X-ray plain film from both of anteroposterior projection and lateral with coronal 60 degrees projection provide satisfactory image of implanted electrode including the shape and the position in the temporal bone. The insertion depth of the electrode can be evaluated indirectly. In contrast, the images from CT scans with 3D reconstruction of the inner ear demonstrate more accurately the shape, the position, and the insertion depth of the electrode. Moreover, each of the electrode pairs can be identified clearly. CONCLUSIONS: X-ray plain film can meet the routine needs of postoperative evaluation of the implanted electrode with several kinds of head position of projection. But CT scans with 3D reconstruction of inner ear provide more accurate image of the spacial relationship of the electrode in the cochlear canal with direct demonstration of electrode insertion depth in the cochlea.