Drug-induced pneumonitis: thin-section CT findings in 60 patients.

PURPOSE: To describe thin-section computed tomographic (CT) findings in patients with drug-induced pneumonitis, to compare these CT findings, and to correlate them with arterial oxygen tension level.

MATERIALS AND METHODS: Thin-section CT scans obtained in 60 patients with drug-induced pneumonitis were evaluated retrospectively. The patients had 31 cases of antineoplastic agent-induced pneumonitis and 29 cases of nonneoplastic agent-induced pneumonitis (antibiotic agent, 20 cases; herbal medicine [sho-saiko-to], four cases; antirheumatic agent, three cases; phenytoin, one case; disodium cromoglycate, one case). CT scans were reviewed by two chest radiologists in consensus. Correlation between arterial oxygen tension level and the extent of disease at CT was available in 21 patients. These two factors were compared by using the Spearman rank correlation coefficient.

RESULTS: The predominant findings in antineoplastic agent-induced pneumonitis were diffuse or multifocal ground-glass opacities with intralobular interstitial thickening. The predominant CT findings in antibiotic agent-induced pneumonitis were patchy ground-glass opacities with centrilobular opacities and interlobular septal lines. The predominant CT findings in herbal medicine-induced pneumonitis were diffuse ground-glass opacities with patchy consolidation. Interlobular septal lines and centrilobular opacities were observed more frequently in antibiotic agent-induced pneumonitis, and intralobular interstitial thickening was observed more frequently in antineoplastic agent-induced pneumonitis. A significant correlation was established between arterial oxygen tension level and extent of disease at CT (r = -0.84, P <.05).

CONCLUSION: In addition to ground-glass opacities and interlobular septal lines, the most common thin-section CT findings were intralobular interstitial thickening, observed in antineoplastic agent-induced pneumonitis, and centrilobular opacities, observed in antibiotic-induced pneumonitis.