Objective: To characterize the temporal chest radiographic findings of fat embolism syndrome.
Material and Method: Twenty-nine patients with clinically diagnosed fat embolism syndrome between 1988-1999 were retrospectively identified from the Trauma Registry of Haborview Medical Center, University of Washington. In twenty-two patients, complete medical records and serial chest radiographs were available. All images were reviewed by a dedicated thoracic radiologist.
Results: Two of 22 patients had normal radiographs throughout hospitalization, while 20/22 developed abnormal chest radiographs. The radiographic findings were consistent with non-specific diffuse pulmonary edema in all abnormal cases. The time to appearance of evident radiographic lung injury was < 24 hours of initial trauma in 10/20 (50%), between 24-48 hours in 4/20 (20%), between 48-72 hours in 5/20 (25%), and 1 patient (1/20, 5%) developed an abnormal chest radiograph after 72 hours. Ten of 20 patients (50%) with abnormal radiographs had complete resolution of the edema pattern within 1 week of development of opacities, 3/20 (15%) cases showed complete radiographic resolution between 1-2 weeks, 2/20(10%) cases showed complete radiographic resolution between 2-3 weeks, 1/20 (5%) showed complete radiographic resolution between 3-4 weeks, and 4/20 (20%) died without resolution of the radiographic finding.
Conclusion: The chest radiographic appearance of fat embolism syndrome is non-specific. Normal radiographs can also be seen. Most patients presenting with a normal initial radiograph develop radiographic evident abnormalities within 72 hours of injury and most cases showed radiographic resolution within 2 weeks of hospitalization. Although chest imaging play a little role in the clinical management of fat embolism syndrome, understanding of temporal presentation and evolution of the otherwise non-specific pulmonary opacities may help to avoid unnecessary evaluation in selected patients.

Keywords: Fat embolism syndrome, Chest radiograph, Pulmonary edema