1. Role of routine nonenhanced head computed tomography scan in excluding orbital, maxillary, or zygomatic fractures secondary to blunt head trauma 9100047 劉芳君

2. The purpose,determine the necessity of a dedicated facial bone/orb(CT),fracture surveillance,blunt head trauma routine nonenhanced head CT scan is negative.

3. A positive head CT scan :an air–fluid level paranasal sinuses,maxillary, orbital, zygomatic osseous structures. Intracranial/parenchymal pathology was not evaluated in this way.

4. Method these 65 patients, none subsequently had a positive facial bone or orbit CT scan. The sensitivity are100%.

5. a negative nonenhanced head CT scan precludes the need for dedicated facial bone,orbital CT scan unnecessary radiation exposure, health care costs, and time

6. The ‘‘clear sinus sign’’ the paranasal sinus walls results in hemorrhage. not associated with paranasal sinus fluid.

7. saves patient unneeded time in the Emergency Department, saves them from potentially harmful radiation saves healthcare dollars.

8. Materials and methods The avera patient age was 44.5 years, and 59% of the patients were male.

9. Nasal bone fractures were noted incidentally study. No evaluation was made regarding intracranial/parenchymal pathology.

10. Fig. 1 Scout image from routine noncontrast head CT scan demonstrating image acquisition protocol

11. Table 1 Correlation of imaging results Head CT+ Head CT+ Totals Facial bone/orbit CT + 42 0 42 Facial bone/orbit CT - 8 65 73 Totals 50 65 115

12. Eight patients with a positive nonenhanced head CT scan subsequently had a negative facial bone/orbit CT. These patients were found to have free fluid within a paranasal sinus on the head CT scan. Etiologically this fluid was determined to be secondary to an isolated nasal bone fracture (in five cases) or an inflammatory process.

13. Discussion scan was defined as showing either an air–fluid level in a paranasal A positive head CT sinus or evidence for a maxillary, orbit, or zygomatic fracture. The free fluid within the sinus results from injury to the lining of the paranasal sinuses. This mucoperiosteu contains a very rich vascular

14. Axial scans through the zygoma are quite sensitive for a displaced fracture Nasal bone fractures are often clinically evident and can be confirmed with plain film radiography

15. Fig. 3 Direct coronal image verifies fractures of the inferior right orbit and lateral wall of the right maxillary sinus

16. Fig. 4 Axial CT image reveals minimally displaced fracture of the left zygomatic process

17. Fig. 5 Plain film image demonstrates a nasal bone fracture