Despite numerous technical improvements, modern diagnosis of lung nodules can still be divided into three partially overlapping stages: (1) detection, (2) characterization, and (3) follow-up and management. With respect to these steps, this article reviews the diagnostic significance of different modalities. New and not definitively evaluated techniques are considered. Furthermore, methods that are not routinely applied but have been published and are thought to have some value in the characterization of pulmonary lung nodules are discussed. Statistical data are included to assist the classification of the results of imaging. Remarks on biopsy of lung nodules to obtain histopathologic correlation complete this overview. The authors are convinced that the established methods (radiography for detection, spiral CT for characterization), after thorough evaluation, will soon be replaced by magnetic resonance imaging (MRI). Recent experience with MRI points to its potential for detection and characterization of pulmonary nodules while avoiding ionizing radiation. The development of indications for MRI of the lung (e.g. paediatric radiology) will be fascinating to observe.