Asbestos-related pleural abnormalities detected by chest X-ray: Fair agreement with detection by computed tomography

The International Labour Office (ILO) 1980 International Classification of Radiograph for Pneumoconioses (ILO 1980) is used widely round the world for the evaluation of dust-exposed workers, whereas computed tomography (CT) has been introduced for more accurate diagnosis of pneumoconioses. This study is aimed to assess whether the chest X-ray can detect pleural abnormalities as accurately as CT in patients with asbestos-related lung diseases in the early stages. Eighty subjects with positive finding in 10 cm x 10 cm CXR were selected from 1178 ex-workers with asbestos exposure for the study. They underwent CXR and CT to be assessed by two ILO 1980 experts for CXR and a chest physician and a radiologist for CT films according to ILO 1980 and the CT criteria, respectively, which we developed. The CT and CXR readings were obtained independently. Scores of the extent of pleural abnormalities agreed on by two readers were compared in CT and CXR. Sensitivity and specificity of CXR for detecting pleural abnormalities by CT result as a gold standard were also calculated. Among the 80 subjects, there were 66 patients (83%) who had pleural abnormalities detected by CXR. Of these 66 persons, CT confirmed 61 subjects to have pleural plaque. The reading results of CXR and CT showed fair agreement with Cohen's weighted kappa of 0.53. Sensitivity and specificity of CXR and CT were 0.94 and 0.73, respectively. Fair agreement was seen between CXR and CT in detecting pleural plaque in terms of extent in dust-exposed workers. Such a standardised system as ILO 1980, CXR is still useful for the screening for pleural abnormalities in dust-exposed individuals.