Differentiating benign and malignant pulmonary lesions with FDG-PET.

The purpose of this retrospective study was to evaluate the efficacy of positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (FDG) to differentiate benign from malignant pulmonary lesions. Fifty-five patients, suspected of having primary pulmonary neoplasm based on chest radiographic findings, underwent FDG-PET scanning. Pathological diagnoses were obtained in 41 patients with a total of 43 pulmonary lesions. The other 14 patients (14 lesions) were followed-up clinically for at least four months. The standard uptake value (SUV) was determined in each patient. The SUV of the 15 benign and 40 malignant pulmonary lesions were 1.60+/-0.42 and 6.14+/-2.67, respectively. If SUV was > 2.50, the pulmonary lesion was considered as a malignant pulmonary lesion. FDG-PET could correctly detect 34 true-positive and 15 true-negative pulmonary lesions. However, 6 false-positive and one-false negative pulmonary lesions were misdiagnosed by FDG-PET. The sensitivity, specificity and accuracy of FDG-PET to differentiate between benign and malignant pulmonary lesions were 94%, 71% and 86%, respectively. FDG-PET can accurately detect malignant pulmonary lesions with a high sensitivity. However, false-positive FDG-PET findings caused by some inflammatory processes may decrease its specificity.