[High-resolution computed tomography compared with the thoracic radiogram and respiratory function tests in assessing workers exposed to silica].

To compare the usefulness of high-resolution computed tomography (HRCT) and chest radiography in the functional evaluation of silica-exposed workers, 27 workers were submitted to posteroanterior and lateral chest radiographs, apex to base HRCT scans and pulmonary function tests. Two experienced readers studied plain films independently to assess small opacities profusion (ILO-UC, Geneva 1980): from 0/- to 3/+. HRCT grading and extent of silicotic nodules and associated emphysema were scored on a four-point scale. Inter-reader analysis showed better agreement for HRCT (K = 0.49) than chest radiography (K = 0.29). Poor agreement was observed between chest radiography and HRCT classes, particularly in the early stages of silicosis. No correlation was observed between chest radiography score and pulmonary function tests, while a significant correlation was observed between HRCT classes (grade and extent of the nodules) and FEV1, MEF50, MEF75, RV and FRC. In conclusion, HRCT exhibited better reproducibility and higher accuracy than chest radiography in identifying the absence of silicotic nodules and in depicting functionally important lesions. To this purpose, HRCT can be considered a useful support to conventional chest radiography.