The Diagnostic Value of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for the Detection of Surgical Site Infection after Spine Surgery.

STUDY DESIGN Retrospective case series. OBJECTIVE The purpose of this study was to assess the diagnostic yield of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) for surgical site infection (SSI) after spine surgery. SUMMARY OF BACKGROUND DATA Diagnosis of SSI in the spine based on F-18 FDG PET/CT requires experienced nuclear medical physicians for a detailed analysis of F-18 FDG distribution pattern. It has also been reported that increases in the maximal standardized uptake values of F-18 FDG (SUVmax) closely correlated with SSI, suggesting potential of more objective and quantitative diagnosis. METHODS We assessed the diagnostic yield of F-18 FDG PET/CT (pattern-based diagnosis by nuclear medical physicians and SUVmax-based diagnosis) for SSI in 52 subjects who underwent spine surgery. The 52 subjects included 11 non-implant and 41 implant cases. F-18 FDG PET/CT was performed in 33 and 19 cases in early (≤12 weeks after the surgery) and late (>12 weeks) phases, respectively. The final diagnosis of SSI was based on the results of pathogen identification, plain radiography, and CT and/or MRI or response to antibiotics and/or reoperation. RESULTS SUVmax-based diagnosis was performed with a cut off value of 5.0 as determined by receiver operating characteristic analysis. Both pattern-based and SUVmax-based diagnoses demonstrated excellent diagnostic yields with high sensitivity (97% and 90%), specificity (100% and 100%), and accuracy (98% and 94%). High diagnostic yields (accuracy of ≥90%) were consistently observed irrespective of presence or absence of implantation or interval between surgery and F-18 FDG PET/CT. CONCLUSION F-18 FDG PET/CT can be the procedure of choice for investigation of SSI in the spine when other imaging fails to provide a definitive diagnosis. LEVEL OF EVIDENCE 4.