The Radiological Diagnosis of Asbestosis

The recognition of different pneumoconioses is usually based on a history of exposure to a given dust together with the presence of characteristic changes in the chest radiograph. This implies that the radiological appearances are reasonably specific. Moreover, if they are to be used not only for clinical diagnosis but also for compensation purposes, and for the study of the disease in relation to factors such as environmental conditions or the changes in lung function, then the radiographic appearances need to be recognized and graded with little variation between different observers. In asbestosis the changes described as being characteristic are a ground-glass mottling of the lung fields, especially in the lower parts, together with pleural thickening and a shaggy border to the heart (Fig. 1). Unfortunately no satisfactory classification of these changes has been produced and the international classification applicable to other pneumoconioses is not easily applied to asbestosis (International Labour Organization, 1959). During an investigation into the significance of lung function changes in asbestosis (Williams and Hugh-Jones, 1960) it became necessary to try and relate the results of lung function tests to an independent assessment of the degree of change in the patient's radiograph. The study described in this paper was therefore made in order to determine not only the specificity of the radiological changes in asbestosis but to see to what extent their diagnosis and grading were affected by observer variability.