· Salts of salicic acid
· 90% of asbestos in the USA is white asbestos (chrysotile) occurs in automotive workers, shipfitters, construction workers
· Asbestos particles invoke a hemorrhagic response in the lung
o Fibers are then coated with a ferritin-like material resulting in ferruginous bodies
o Produces its damage in respiratory bronchioles and alveoli
· Affects lower lobes first
· The presence of pulmonary parenchymal changes differentiates asbestosis from asbestos-related pleural disease
o Opacities are small and irregularly shaped
o Cardiac silhouette may become shaggy
· Imaging findings
o All patients with asbestos-related pleural disease have, by definition, some pleural involvement
§ Pleural involvement without parenchymal disease is common
§ Pleural plaque
· Parietal pleural plaques in the mid lung are the most common asbestos-related disorder and are usually bilateral
· They occur most often in the 6th-9th interspaces usually sparing the apices and lung bases and involve the parietal pleura
§ Diffuse pleural thickening
· Less common than pleural plaques
· Diffuse pleural thickening involves diaphragmatic pleura, blunting of costophrenic sulci and lateral pleural thickening