Enhanced Uptake of FDG in PET/CT After the Use of Bone Wax During Sternotomy.

OBJECTIVE

Physiologic healing processes and foreign body reactions can mimic infective conditions in 18F-FDG-PET/CT for the detection of deep sternal wound infections. To date, nothing is known about the metabolic presentation of surgically applied bone wax to the sternum for hemostasis during sternotomy in 18F-FDG-PET/CT imaging. Therefore, this study aims to assess the sternal FDG uptake after the application of bone wax during sternotomy.

METHODS

A total of 25 patients with a history of cardiac surgery (1.3-5.5 years ago) were examined by 18F-FDG-PET/CT with dual time point imaging. The sternal FDG uptake was assessed visually (as positive or negative) and metrically using the maximum standardized uptake values (SUVmax) calculated automatically. The SUVmax was compared between the patients with and without the use of bone wax and among patients with and without positive sternal findings in the visual analysis. A correlation analysis was performed between the time since surgery and the sternal SUVmax.

RESULTS

In all eight patients (32%) had received bone wax. In those patients, the mean sternal SUVmax was higher compared to the group without bone wax, both in the early (4.74 ± 1.28 vs. 3.70 ± 1.44; p = 0.0969) and in the late images (6.62 ± 2.67 vs. 4.36 ± 1.44; p = 0.0289). Moreover, the use of bone wax was strongly associated with positive sternal findings in the visual analysis (OR = 10; 95%CI = 0.995-100.462; p = 0.0421). The correlation analysis revealed a slightly decreasing trend without significance (Spearman's ρ = -0.139; p = 0.505).

CONCLUSION

The use of bone wax during sternotomy could be associated with increased sternal uptake of FDG on 18F-FDG-PET/CT, even several years after surgery. This finding should be considered in the evaluation of potential deep sternal wound infections.