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Purpose
The aim of this study was to quantify the contribution of FDG PET to the diagnostic assessment of fever of unknown origin (FUO), taking into account the diagnostic limitations resulting from the composite nature of this entity.
Methods
The PubMed/MEDLINE database was searched from 2000 to September 2015. Original articles fulfilling the following criteria were included: (1) FUO as the initial diagnosis, (2) no immunosuppressed or nosocomial condition, (3) final diagnosis not based on PET, (4) a follow-up period specified, (5) adult population, and (6) availability of adapted data for calculation of odds ratios (ORs). ORs were computed for each study and then pooled using a random effects model. Stratification-based sensitivity analyses were finally performed using the following prespecified criteria: (a) study design, (b) PET device, (c) geographic area, and (d) follow-up period.
Results
A meta-analysis of the 14 included studies showed that normal PET findings led to an increase in the absolute final diagnostic rate of 36 % abnormal PET findings to an increase of 83 %, corresponding to a pooled OR of 8.94 (95 % CI 4.18-19.12, Z=5.65; p<0.00001). The design of the studies influenced the results (OR 2.92, 95 % CI 1.00-8.53 for prospective studies; OR 18,57, 95 % CI 7.57-45.59 for retrospective studies; p=0.01), whereas devices (dedicated or hybrid), geographic area and follow-up period did not.
Conclusion
Abnormal PET findings are associated with a substantially increased final diagnostic rate in FUO. Consequently, FDG PET could be considered for inclusion in the first-line diagnostic work-up of FUO. Further randomized prospective studies with standardized FDG PET procedures are warranted to confirm this first-line position.