Lines and stripes: where did they go?--From conventional radiography to CT

Frontal and lateral radiography has traditionally been used to evaluate the chest, although computed tomography (CT) and high-resolution CT are increasingly being used as an adjunct to conventional radiography for the evaluation of parenchymal and mediastinal disease. Nevertheless, radiography remains a very important modality in this context, and use of chest radiography alone can provide a vast amount of useful information. This information is derived from the configurations and interrelationships of the anatomic structures in the lung, mediastinum, and pleura and forms the basis of the "lines and stripes" concept, which plays a valuable role in establishing a diagnosis before proceeding to CT. The inability to recognize that a chest radiograph is abnormal owing to displacement of one of these lines or stripes may lead to failure to request a potentially valuable CT examination. Radiologists must be familiar with the anatomic basis of these mediastinal lines and stripes and be able to recognize their normal and abnormal appearances. In this way, they can develop an appropriate differential diagnosis prior to obtaining additional information with chest CT.