多层螺旋CT在颌骨牙齿显示中的临床价值初步探讨

目的：探讨多层螺旋CT（16层）三维（3D）重建技术在显示颌骨牙齿中的临床应用价值。方法：23例患者行多层螺旋CT轴位扫描，层厚2．5mm。采用最大密度投影法（MIP），表面遮盖显示（SSD）和多平面重建法（加艰）3种方式重建图像。将横轴位图像与不同方法重建的图像进行对比。结果：17例不易定位的埋伏阻生牙及多生牙在上颌骨中的位置、数目、牙轴的方向、牙体形态等，均被清晰、准确地显示出来。23例中17例见牙体长轴排列不整齐，倾斜、旋转、重叠，牙齿长轴间距离不等，其中15例共有23颗埋伏牙。横轴位图像能包括全部信息。SSD可以显示牙齿与颌骨的外部轮廓、整体形态以及牙齿排列与颌骨之间的关系。MIP能清楚显示牙齿全貌、牙齿纵向排列关系；MPR则对根尖骨质、根尖与牙槽骨的局部关系显示更清晰。结论：多层螺旋Cr3D重建技术是一种能展示牙齿立体形态影像的新技术。轴位图像、MIP、SSD及MPR联合应用能明确病变性质，立体、直观、多方位提供信息。3D重建技术对埋伏阻生牙及多生牙的定位精确，能清晰显示其形态、唇颊侧或舌侧位置、萌出方向及邻牙关系，3D重建技术可作为颌面外科处理和正畸治疗前的重要检查手段。

Preliminary study of clinical value in displaying the tooth of jaw bone by multi-slices spiral CT

Objective:To evaluate the clinical value in displaying the tooth of jaw bone by multi-slices spiral CT(MSCT 16F)'s three-dimensional reconstruction technique.Methods:There are 23 cases which were examed by helical scanning of multi-slices spiral CT with 2.5mm slice thickness.The images were reconstructed by maximum intensity projection( MIP), surface shaded display (SSD) and multiplanar reconstructions (MPR),and compared with which obtained by scanning in axial orientation.Results:The position number direction of tooth axial shape of tooth body of 21 cases buried teeth which were difficult to locate can be displayed clearly and acurately.The axial images included all of the information.SSD, and they were morphologically delineated on MIP through various angles.Conclusion:The 3D reconstruction technique of MSCT is a new technique to display the stereoscopic configuration of teeth.The combinaton of MIP,SSD, MPR and the axial images provides valuable anatomic and diagnostic information helpful for the surgeons to structure and determine the treatment protocol for the dental orthopaedics.3D reconstruction technique can be regarded as an important examing mean before surgical treatment.