The role of FDG PET-CT in differential diagnosis of pleural pathologies

Abstract

ObjectiveThis study has aimed to evaluate the impact of F18 Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (FDG PET-CT) in the differential diagnosis of malignant and benign pleural lesions in patients with suspected malignant pleural mesothelioma (MPM). Material and methodsFifty patients (32 females, 18 males; age range 24–79 years) with pleural thickening, fluid, plaques or calcification on previous CT scan were examined with FDG PET-CT. PET-CT imaging was obtained 1h after FDG injection. In 12 patients, delayed imaging from the thoracic region was performed 2h after injection. FDG uptake was evaluated visually and semiquantitively using standardized uptake value (SUV). FDG PET-CT findings were compared with histopathologic diagnosis. ResultsThirty-nine patients had increased FDG uptake in pleural lesions but PET-CT results were negative in 11 patients. When compared with histopathological results in FDG positive group, 34 patients had MPM, 5 had benign pathology; in FDG negative group 8 patients had benign pathology, 3 had MPM. Of patients with delayed imaging, 9 showed increased SUV but 3 had a decreased SUV on delayed images. Increased SUV group had 4 MPM, 5 benign pathology (3 chronic granulomatous inflammation, 2 benign asbestotic plaque). Decreased SUV group all had benign pathology (fibrosis, chronic inflammation, myofibrosis). DiscussionFDG PET-CT is a useful imaging modality in differential diagnosis of malignant and benign pleural lesions. Delayed imaging seems to be useful if there is a decrease in SUV suggesting a benign pathology but does not seem to contribute to the differential diagnosis if the SUV is increased.