Classification of pneumoconiosis by high speed, high resolution computed tomography (HSRCT)

Improvement in CT technology now makes possible imaging of the lung with excellent anatomic details, demonstrating patterns of pulmonary abnormalities induced by dust inhalation. By circumventing the summation of lung structures in complex regions such as apices, paratracheal, pericardiac, margin of chest walls, diaphragmatic regions and pulmonary vessels, HSRCT can confirm the presence of interstitial fibrosis associated with areas of lung destruction and disorganization of lung architecture. A comparative study of chest radiographs and computed tomograms was made in 93 cases of pneumoconiosis, including silicosis, asbestosis, welder's lung, foundry worker's lung and activated carbon pneumoconiosis, the profusion of which was classified as 0/1 to 3/3 following ILO 1980 International Classification of Radiographs of Pneumoconioses. The codification and scoring of chest CT of pneumoconiosis is based on ILO 1980 and JAPAN 1978 Classification. The purpose of these is to codify chest CT findings in a simple and reproducible manner. Detectability of small rounded or irregular opacities in CT images is higher than in chest radiographs in low profusion and is far better for visualization of emphysematous changes (89% in 87 cases exclude 0/1), abnormalities of pulmonary vessels and pleura. There is less relation between profusion and emphysematous changes in scoring method. However, it is difficult to differentiate small rounded opacities and pulmonary vessels in thin slice CT images. (author)