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

The aim of this study is to measure the value of 2D-CT and 3D-CT in diagnosing mid-facial fractures.

50 patients who suffered from facial trauma were scanned with both conventional axial-CT (3 mm thickness) and 3D reconstruction (surface shaded display, SSD). The scanning region was ranged from the upper teeth to superior edge of the orbit. Coronal-CT imaging was performed in 21 patients in order to compare with that of axial and 3D CT images.

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 sides), 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 fracture of anterior wall of the maxilla (60/57 sides) and shapes of the facial fracture. 2D-CT is similar to 3D-CT in diagnosing fractures of nasal bone (20 sides), zygomatic bone and arch (24 sides). Owing to the partial volume effect, the medial wall of normal or abnormal orbit could not be correctly evaluated on 3D reformation images.

It is concluded that 2D-CT should be regarded as the foundations of diagnosing facial fractures, and 3D-reconstruction as a useful complementary tool.