INTRATHORACIC CALCIFICATIONS - RADIOGRAPHIC FEATURES AND DIFFERENTIALDIAGNOSES

Intrathoracic calcifications occur in a wide variety of disorders. Alt hough they are usually harmless sequelae of remote processes, calcific ations provide important information for establishing the diagnosis or for evaluating the progression of known disease. They may arise in th e pulmonary parenchyma, mediastinum, hilar and mediastinal lymph nodes , pleura, chest wall, or any combination of these structures. The caus e of the calcifications may be determined by means of the location and pattern of the calcifications within the lung parenchyma and knowledg e of the associated clinical features. Calcifications in the thorax ar e frequently manifestations of previous infectious processes. Less oft en, they may be due to neoplasms, metabolic disorders, occupational ex posure, or previous medical therapy. Large intrathoracic calcification s are usually identified on conventional chest radiographs; detection of smaller calcifications may require use of other imaging modalities, such as dual-energy digital radiography, fluoroscopy, radionuclide sc anning, computed tomography (CT), and high-resolution CT.