Imaging of secondary pulmonary changes in central bronchial carcinomas by F-18-FDG-PET

Aim: The presented study was performed in order to evaluate the potential i nterference of secondary pulmonary changes (dystelectasis, retention pneumo nia) with bronchial carcinomas in F-18-FDG-PET. Method: A retrospective ana lysis of F-18-FDG-findings in 33 patients with bronchial carcinoma (staging ) was performed. Seven out of fourteen patients with central tumor localisa tion had secondary pulmonary changes (thorax-x-ray, CT), which were classif ied as dyslelectasis or atelectasis in five cases and as retention pneumoni a in two cases. Results: Whereas dystelectasis and atelectasis without clin ical signs of infection showed only mild to moderate FDG-accumulation (SUV 1.0-2.5; mean: 1.74), an intense FDG-uptake in the two cases with retention pneumonia (SUV 8.4 and 5.5) was observed. Despite of the typical wedge-lik e shape of pneumonia, differentiation between bronchial carcinoma and pneum onia can be a problem. Conclusion: We suggest, that an antibiotic treatment in patients with known retention pneumonia should be performed prior to th e PET-scan in order to reduce the interference of inflammatory changes.