Utility of 18F-FDG PET/CT for Suspected Infection in the Inpatient Setting: a Single Centre Retrospective Cohort Study

• Did PET contribute to diagnostic yield?:

• 1 = Yes: PET led to a finding either definitive e.g. confirmed by gold standard (microbiology, histopathology, intraoperative findings etc) or contributory, which guided diagnosis or management even without gold standard confirmation. Examples of contributory: PET showing vascular graft uptake, not explanted due to risk but presumptively treated Vertebral discitis suggested by PET, biopsied without culture, but presumptively treated and clinically improved PET negative - antibiotics ceased, patient remained well
• 0 = No: PET provided no new information, was misleading (i.e. PET result contradicted by later results), or no action was taken based on PET

• Clinical change in management: was clinical care altered compared to the documented plan prior to PET? 0 = no, 1 = yes

• Yes: antimicrobial therapy, procedures/interventions (PET-guided site biopsy, or surgery/drainage), diagnostics e.g. further focussed imaging, or disposition e.g. palliative care transition
• No: there was no change to the management plan, or the plan was already determined by other data

Examples:

• PET confirmed a suspected diagnosis but the treatment plan was unchanged
• PET provided supporting evidence but no explicit management adjustment was documented
• PET was negative and no further management steps were taken because there was a pre-existing plan

•Change in antimicrobial duration/spectrum/therapeutic procedure: this change occurred as a result of PET

• Final diagnosis: infection = 1, non-infectious = 2, malignancy = 3, unresolved = 4