Diagnostic Yield of 18F-FDG PET After Lung Transplantation: A Single-center, Retrospective Cohort Study

BACKGROUND: To investigate the diagnostic yield of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in lung transplant recipients. METHODS: A single-center, retrospective cohort study including 234 18F-FDG PET examinations in 199 lung transplant recipients. Indication for PET referral, 18F-FDG PET diagnosis/findings and final clinical diagnosis were classified into 3 groups: malignancy, infection/inflammation not otherwise specified, and chronic lung allograft dysfunction with restrictive allograft syndrome phenotype. Sensitivity/specificity analysis was performed to determine accuracy of 18F-FDG PET in each group. RESULTS: Sensitivity of 18F-FDG PET for malignancy was 91.4% (95% confidence interval, 82.5%-96.0%) and specificity was 82.3% (95% confidence interval, 74.5%-88.1%). Infection/inflammation not otherwise specified and restrictive allograft syndrome as indication for 18F-FDG PET comprised relatively small groups (14 and 31 cases, respectively). In addition, 18F-FDG PET revealed clinically relevant incidental findings in 15% of cases. CONCLUSIONS: Referral for 18F-FDG PET after lung transplantation mainly occurred to confirm or rule out malignancy. In this specific setting, 18F-FDG PET has a high diagnostic yield. Accuracy of 18F-FDG PET for other indications is less clear, given small sample sizes. Clinically relevant diagnoses, unrelated to the primary indication for 18F-FDG PET, are found relatively often in this immunocompromised cohort.