Diffuse pleural thickening in an asbestos-exposed population: prevalence and causes

AJR Am J Roentgenol. 1985 Jan;144(1):9-18. doi: 10.2214/ajr.144.1.9.


Two types of pleural reaction have been described in association with asbestos exposure: pleural plaques and diffuse pleural thickening. This study was undertaken to determine the prevalence and causes of diffuse thickening in asbestos-exposed persons. Serial chest radiographs in 1373 exposed individuals and 717 controls were interpreted according to the ILO scheme by two B readers. Diffuse pleural thickening was defined as a smooth, noninterrupted pleural density extending over at least one-fourth of the chest wall, with or without costophrenic angle obliteration. Among the exposed group, plaques and diffuse thickening occurred with almost equal frequency, 16.5% and 13.5%, respectively. Of the 185 cases with diffuse thickening, the radiographic appearance was most often due to the residual of a benign asbestos effusion (31.3%) or confluent plaques (25.4%). The most commonly held explanation of diffuse thickening, an extension of pulmonary fibrosis to the visceral and parietal pleura, was actually infrequent (10.2%). Among the group with diffuse thickening without asbestosis, the forced vital capacity and single-breath diffusing capacity were significantly lower than those of comparable normal persons and those with confluent plaques.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Asbestosis / diagnostic imaging*
  • Asbestosis / pathology
  • Humans
  • Male
  • Middle Aged
  • Pleura / pathology
  • Pleural Diseases / diagnostic imaging*
  • Pleural Diseases / pathology
  • Radiography