Imaging evaluation of the solitary pulmonary nodule

Solitary pulmonary nodules (SPNs) are common incidental findings in patients undergoing thoracic imaging studies. An SPN is a rounded opacity, circumscribed or poorly defined, measuring up to 3 cm in diameter. The radiologic characteristics, medical history, and physical examination results are helpful for distinguishing between benign and malignant SPNs. An estimated 150,000 SPNs are identified at chest radiography each year, making it important for physicians to understand how to characterize them and evaluate patients for potential malignancy. A number of features visible at thoracic computed tomography (CT) are useful for determining whether an SPN is benign or malignant. 2-F-fluoro-2-deoxy-D-glucose positron emission tomography-CT (PET/CT) plays an important role in the diagnosis and management of lung cancer and is an increasingly valuable tool for the characterization and management of SPNs. Unlike CT and magnetic resonance imaging, PET provides information regarding the metabolic activity of a nodule. The information provided by PET/CT imaging allows for both morphologic and anatomic characteristics and physiological data in the form of metabolism within the nodule itself. The information gained from PET is extremely useful for directing patient management and may obviate the need for invasive diagnostic procedures.