Pulmonary involvement in polymyositis and dermatomyositis: sequential evaluation with CT.

OBJECTIVE: The characteristic findings of pulmonary involvement in polymyositis (PM) or dermatomyositis (DM) and the change in findings before and after treatment were evaluated with sequential high-resolution CT studies.

MATERIALS AND METHODS: CT images of pulmonary involvement in 19 patients with PM or DM were reviewed. During a period of 2-61 months, 17 of these patients underwent sequential CT before and after treatment with corticosteroids, immunosuppressants, or both.

RESULTS: Findings of the initial CT studies included pleural irregularities and prominent interlobular septa (n = 19), ground-glass attenuation (n = 19), patchy consolidation (n = 19), parenchymal bands (n = 15), irregular peribronchovascular thickening (n = 15), and subpleural lines (n = 7). Honeycombing was not detected on any CT images. These findings were more remarkable in the lower portion and the subpleural area of the lungs. In 16 of the 17 patients who underwent sequential CT conditions such as patchy consolidation, parenchymal bands, and irregular peribronchovascular thickening improved, becoming pleural irregularities and prominent interlobular septa, ground-glass attenuation, and subpleural lines on follow-up CT scans.

CONCLUSION: Consolidation with patchy and subpleural distribution, parenchymal bands, and irregular peribronchovascular thickening were characteristic and reversible CT findings in patients with PM or DM.