[Role and limitations of plain radiography in chest radiology].

Despite the recent development of diagnostic modalities such as CT and MRI, plain radiography continues to play an important role in chest radiology. Chest radiography remains the imaging modality of choice for initial examinations because it offers simplicity, low cost, and a large amount of information. It is important for radiologists to understand normal anatomy and variants simulating disease to avoid false-positive interpretations of chest radiographs and unnecessary CT examinations. It should be noted that many cases can be diagnosed correctly by chest radiographs alone. Only after careful evaluation of an abnormality on chest radiograph should CT examination be performed. We should also be aware that some serious chest diseases, including miliary tuberculosis, can present normal chest radiographs in the early stage. In such patients with respiratory symptoms, even when the chest radiograph is negative, CT examination should be performed promptly to avoid disease progression.