This study was carried out to improve the medical surveillance program of workers exposed to asbestos by examining the usefulness of High Resolution Computed Tomography (HRCT) in the diagnosis of asbestos-related lung disease.

The study subjects comprised 162 workers in a ship-repairing yard, 68 of whom had been directly exposed to asbestos and 94 indirectly exposed. The ‘Occupational Safety & Health Administration (OSHA) asbestos standard, medical surveillance program’ and HRCT were conducted to analyze the aspects of the asbestos-related lung disease. The OSHA asbestos standard, medical surveillance program consists of simple chest x-ray, spirometry and medical questionnaire.

Seventeen (10.5%) of the 162 subjects, 10 (14.7%) directly exposed and 7 (7.4%) indirectly exposed, revealed asbestos-related lung disease on HRCT. The sensitivity and specificity of simple chest x-ray for asbestos-related lung disease were 70.6% and 98.6%, and the positive and negative predictive values were 85.7% and 96.6% respectively, as compared with HRCT. HRCT was an effective diagnostic tool especially to detect early asbestos-related lung disease. The study results indicated a relative significant association between the results of spirometry and HRCT. The variables significantly associated with asbestos-related lung disease on HRCT were work duration, smoking history (pack-years), past history of respiratory disease, cough and dyspnea.

In the diagnosis of asbestos-related lung disease, HRCT should be considered not only for workers with positive findings on simple chest x-ray, but also workers with specific findings on spirometry, occupational history, smoking history, and past history of respiratory disease, or with respiratory symptoms such as cough and dyspnea.