PET scanning and the solitary pulmonary nodule

The finding of a solitary pulmonary nodule on a chest radiograph is a common problem in pulmonary medicine and is seen in about 1 in 500 chest radiographs. Of the benign lesions, 80% are infectious granulomas, 10% are hamartomas, and the remaining 10% are caused by a variety of rarer disorders including noninfectious granulomas and other benign tumors. The prevalence of malignancy ranges from 10% to 68% in the literature. Because of the high prevalence of malignancy and the poor survival for lung cancer, early detection, characterization, and directed treatment are important. Positron emission tomography with 18-Fluorodeoxyglucose (FDG-PET) can play an important role in the evaluation and management of solitary pulmonary nodules. This includes improved characterization of solitary pulmonary nodules with very high negative predictive value and improved staging information when performed in association with CT, especially for nodal staging and identification of unsuspected stage IV disease. PET also provides additional information for management of solitary pulmonary nodules by estimating the probability of malignancy.