Differentiating solitary pulmonary metastases in patients with extrapulmonary neoplasmas using FDG-PET

The purpose of this preliminary study is to evaluate the characteristics of solitary pulmonary lesions in patients using extrapulmonary neoplasmas with 18F-fluoro-2-deoxyglucose positron emission tomography (FDG-PET). Thirty-two patients with extrapulmonary neoplasmas who had solitary pulmonary lesions and were suspected for pulmonary metastasis underwent an oncological survey with FDG-PET. Standard uptake value (SUV) and the ratio of lesion-to-background (L/B ratio) were used as parameters to differentiate and characterize the solitary pulmonary lesions. Using SUV > 2.5 or L/B ratio > 3 as the cutoff to diagnose malignancy, FDG-PET correctly identified 29 true-positive cases. However, FDG-PET failed to interpret two false-positive and one false-negative cases. The accuracy of FDG-PET was 91%. We concluded that FDG-PET is an accurate modality to differentiate solitary pulmonary lesions in patients with extrapulmonary neoplasmas.