Diagnostic utility of F-FDG PET/CT in fever of unknown origin among patients with end-stage renal disease treated with renal replacement therapy.

OBJECTIVE

To evaluate the role of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) in identifying the cause of fever of unknown origin (FUO) in patients on renal replacement therapy (RRT) for end-stage renal disease (ESRD).

SUBJECTS AND METHODS

We retrospectively reviewed the F-FDG PET/CT scans of 46 patients with a mean age of 39.28±12.50 years on RRT for ESRD. All patients with abnormal scans had histopathologic examination and microbial cultures of tissue samples from areas with increased standardized uptake value maximum (SUVmax) suggesting the cause of FUO in the F-FDG PET/CT scan. Fluorine-18-FDG PET/CT was considered helpful if it led to the diagnosis of the cause of FUO after histopathologic and microbiologic examinations.

RESULTS

Fluorine-18-FDG PET/CT was helpful in identifying the cause of FUO in 22/46 patients (47.83%). Infection was the cause of fever in all these 22 patients. C-reactive protein (CRP) (P=0.003) and procalcitonin levels (P=0.021) were higher in patients with helpful F-FDG PET/CT. No significant difference was found in blood sugar levels and leucocytes counts between patients with helpful F-FDG PET/CT outcome and those without. By multiple regression analysis, the odds of a helpful F-FDG PET/CT increased with every unit increase in CRP level (OR: 1.009; 95% CI: 1.003-1.016; P=0.005).

CONCLUSION

About half of the F-FDG-PET/CT scans (22/46) identified the cause of FUO in patients on RRT for ESRD. The clinical utility of F-FDG PET/CT in this group of patients is comparable to its average performance in the unselected patients' population evaluated for FUO. A higher CRP level was predictive of a positive F-FDG PET/CT outcome.