二维和三维CT对面中部骨折诊断的对比研究

目的 评价二维CT和三维CT对面中部骨折诊断的价值。方法 对50例面部创伤患者行横断二维CT扫描（层厚3mm）,并进行三维重建（表面阴影遮盖显示法,SSD）。扫描范围包括上颌牙列至眼眶上缘。21例患者尚行冠状面CT扫描,以作对照。结果 和三维CT相比,横断二维CT较三维CT更好地显示上颌内壁（5／0侧）,上颌外后壁（49／44侧）,上颌牙槽（14／12侧）,眼眶外壁（34／31侧）和蝶骨翼突区（19／9侧）的骨折。三维CT在显示上颌前壁骨折（60／57侧）和骨折形态方面优于二维CT。横断二维CT和三维CT对鼻骨（20侧）和颧骨颧弓骨折（24侧）的显示呈一致性。由于部分容效应,SSD三维CT通常不能区别正常或异常的眼眶内壁。结论 二维CT是诊断面部骨折的基础,三维CT能对二维CT作有益补充。

Comparison of 2D-CT and 3D-CT in diagnosing mid-facial fractures

Objective The aim of this study is to measure the value of 2D-CT and 3D-CT in diagnosing mid-facial fractures Methods 50 patients who suffered from faci al trauma were scanned with both conventional axial-CT (3 mm thickness) and 3D reconstruction (surface shaded display, SSD) The scanning region was ranged fr o m the upper teeth to superior edge of the orbit Coronal-CT imaging was perfor me d in 21 patients in order to compare with that of axial and 3D CT images Results Axial 2D-CT can be better to identify facial fractures than 3D reconstruction in such sites that are medial wall of the maxilla (5/0 sides) , lateroposterior wall of the maxilla (49/44 sides), upper alveoli (14/12 si des), lateral wall of the orbit (34/31 sides), and pterygoid process of the sphenoid bone (19/9 sides ) Three-dimensional reconstruction was superior to 2D-CT in demonstrating fr act ure of anterior wall of the maxilla (60/57 sides) and shapes of the facial fract ure 2D-CT is similar to 3D-CT in diagnosing fractures of nasal bone (20 side s), zygomatic bone and arch (24 sides) Owing to the partial volume effect, the me d ial wall of normal or abnormal orbit could not be correctly evaluated on 3D refo rmation images Conclusion It is concluded that 2D-CT should be regarded as the foundations of diagnosing facial fractures, and 3D- reconstruction as a useful complementary tool