Background: The noninvasive diagnosis of chronic
musculoskeletal infections remains a challenge. Recent studies have
indicated that fluorine-18 fluorodeoxyglucose-positron emission
tomography is a highly accurate imaging technique and is significantly more
accurate than the combination of a bone scan and a white blood-cell
scan for the diagnosis of chronic infection in the central skeleton
(p < 0.05). However, patients who had had surgery within
the previous two years were excluded from study. It was our aim
to evaluate the technique in an unselected, clinically representative
Methods: Sixty patients with a suspected chronic
musculoskeletal infection involving the central skeleton (thirty-three
patients) or the peripheral skeleton (twenty-seven patients) were
studied with fluorine-18 fluorodeoxyglucose-positron emission tomography.
Thirty-five patients had had surgery within the previous two years.
The fluorine-18 fluorodeoxyglucose-positron emission tomography
studies were read in a blinded, independent manner by two experienced
readers. The final diagnosis was based on histopathological studies
or microbiological culture (eighteen patients) or on clinical findings
after at least six months of follow-up (forty-two patients).
Results: On the final composite assessment, twenty-five patients
had infection and thirty-five did not. All twenty-five infections
were correctly identified by both readers. There were four false-positive
findings; in two of these cases, surgery had been performed less
than six months prior to the study. The sensitivity, specificity,
and accuracy were 100%, 88%, and 93% for
the whole group; 100%, 90%, and 94% for
the subgroup of patients with a suspected infection of the central
skeleton; and 100%, 86%, and 93% for
the subgroup of patients with a suspected infection of the peripheral
skeleton. Interobserver agreement was excellent (kappa = 0.97).
Conclusions: Fluorine-18 fluorodeoxyglucose-positron
emission tomography is highly accurate as a single technique for
the evaluation of chronic musculoskeletal infections. It is especially
valuable in the evaluation of the central skeleton, where white
blood-cell scans are less useful. Because of its simplicity and
high degree of accuracy, it has the potential to become a standard
technique for the diagnosis of chronic musculoskeletal infections.
Further studies are needed to assess its ability to identify infections
at the sites of total joint replacements and to distinguish infection
from aseptic loosening of these prostheses.