Digital volume tomography in the diagnosis of nasal bone fractures

Digital volume tomography (DVT) is a kind of cone beam computed tomography and enables high quality 3D images of osseous structures. It is a well-established diagnostic tool in dentistry. High detail resolution is reached with a reduced exposition of radiation dose in comparison to conventional computed tomography. The data volume can be analysed in three orthogonal plains, which can be changed in angle arbitrarily. The aim of the study was to evaluate, if and in which performance DVT is able to detect discrete nasal bone fractures that cannot be seen in conventional radiography occasionally. DVT was performed in sixty-five patients with suspected nasal bone fracture. Five of these patients underwent lateral radiographs of the nasal bones in other departments which failed to show any radiologic signs of a nasal bone fracture, whereas DVT showed clear fracture lines. DVT-findings were also used to classify fractures according to their dimensions. Additionally DVT enabled the reconstruction of three-dimensional volume images. With this technique it is possible to get an image of the extent of the nasal bone fracture and the dislocation of the fragments. Because of these facts as well as its high resolution and low radiation dose, DVT can be recommended as the routine radiological examination in suspected nasal bone fractures.