びまん性粒状影―じん肺とその鑑別疾患について

Diffuse fine nodules：pneumoconiosis and its differential diagnosis

じん肺は，粉じんを吸入することによって肺に生じた線維増殖性変化を主体とする疾病と定義される（じん肺法）。じん肺の多くは職業性の無機粉じん曝露が原因であり，原因物質として，石炭（炭鉱夫じん肺），遊離珪酸（珪肺），珪酸化合物（石綿肺など），ベリリウム（ベリリウム肺）などが知られている。本邦におけるじん肺の発生率は，作業環境の改善や予防知識の普及により減少傾向にあるが，年間に届け出される要療養認定患者数は後を絶たず，依然として重要な職業性肺疾患である。

The chest radiography has been an essential examination for detection and characterization of occupational lung diseases for many years. However, it is clear that CT is a more sensitive diagnostic tool to demonstrate the lung parenchymal changes of pneumoconiosis. Furthermore, CT is useful to differentiate pneumoconiosis and other diffuse lung diseases that will show diffuse fine nodules that is similar to silicosis on chest radiography, such as sarcoidosis, pulmonary tuberculsosis, and pulmonary langerhans cell histiocytosis. Although CT screening for pneumoconiosis will need more consideration about benefits, harms and economic efficiency, recent advance of CT technology will allow us for CT screening of pneumoconiosis.