When to Consider FDG-PET Imaging in Solitary Pulmonary Nodules

The primary goal in the evaluation and management of solitary pulmonary nodules is prompt resection of all malignant nodules and the avoidance or minimization of thoracotomy in benign nodules. Despite the use of thin-section CT scans of the chest, a substantial proportion of nodules remain radiographically indeterminate. It is estimated that 15,000 to 25,000 thoracotomies are likely to be performed annually for benign lung nodules.Positron emission tomography (PET) using fluorine 18-fluoro-2-deoxy-D-glucose (FDG) is a new, noninvasive imaging test that can detect increased FDG uptake in metabolically active malignant cells. Data in the literature suggest that FDG-PET imaging has a high degree of accuracy in differentiating benign from malignant solitary pulmonary nodules and has no associated morbidity. The diagnostic sensitivity is 97% (range 88% to 100%) and the specificity is 86% (range 79% to 100%), with an overall accuracy of 93% (range 90% to 100%). The use of FDG-PET imaging in the evaluation of solitary pulmonary nodules may reduce invasive procedures such as transthoracic needle lung aspiration biopsy and thoracotomy, thus avoiding the morbidity and mortality of these procedures and having the potential for significant cost savings.Suitable subjects for initial FDG-PET imaging would include patients with noncalcified solitary pulmonary nodules less than 3 cm in diameter and who are good surgical candidates for thoracotomy. A patient with a positive PET scan can be referred directly for thoracotomy, whereas a patient with a negative PET scan can be considered for close follow-up and observation.