Grading of Fibrosis and Cell Infiltration of the Lung
The degree of lung fibrosis was evaluated utilizing CT scans. The scans were performed on scanners (GE 9800 or GE 8800) at 1- or 1.5-cm and interval using 10-mm coUination from the apex of the lungs to the base of the diaphragm during breath holding after deep inspiration in all patients. Slices below the level of the carina were selected and each slice was evaluated for the presence of irregular linear or reticular opacities that were considered as fibrosis. The results were classified into three grades. If the fibrotic changes were present in more than one third of the slices, we categorized the case as grade 2; if present in less than one third, grade 1; and if absent, grade 0. These assessments were done independently by more than three pulmonologists who were blinded to clinical information in our group and the consensus results were obtained. Cellular infiltration was evaluated by the same methods. Small nodular opacities or ground-glass opacities were considered to be indicative of cellular inflammation.
Pulmonary Function Tests
Spirometry was performed on an automated pulmonary analyzer utilizing a constant resistance ratio hot wire anemometer. Pulmonary diffusing capacity was measured by the single-breath carbon monoxide method. Predicted values for spirometry are from Baldwin and associates and Needham et al,e and for pulmonary diffusing capacity from Miyazawa and coworkers.
Data are expressed as mean±SD and analyzed by unpaired Students t test; p<0.05 was considered a significant difference.