Dual time point FDG PET for evaluation of malignant pleural mesothelioma

To evaluate whether 2-deoxy-2-18F-fluoro-D-glucose (FDG) positron emission tomography (PET) is more useful in differentiating malignant from benign pleural lesions, and whether delayed FDG PET imaging can improve the diagnostic performance in patients with suspicion of malignant pleural mesothelioma (MPM).

Thirty-three patients who were suspected of having MPM were examined with FDG PET. PET imaging (whole body) was performed at 60 min (early) post-FDG injection and repeated at 120 min (delayed) after injection only in the thoracic region. We evaluated the FDG uptake visually and semiquantitatively. The semiquantitative analysis using the standardized uptake value (SUV) was determined for both early and delayed images (SUVearly and SUVdelayed, respectively).

The final diagnosis was MPM in 17 patients and benign pleural disease in 16 patients. The sensitivity, specificity, and accuracy to detect MPM on both early and delayed PET were all 88%. The mean value of SUVdelayed in MPM was significantly higher than that of SUVearly (P < 0.001). The mean values of SUVearly and SUVdelayed in MPM were significantly higher than the corresponding values in benign pleural disease (P < 0.01, respectively).

FDG PET seems to be a useful imaging modality for differential diagnosis of MPM. In addition, the diagnostic performance on delayed PET was the same as that on early PET, although SUVdelayed was significantly higher than SUVearly in patients with MPM.