Pulmonary sarcoidosis: changes on follow-up CT examination

Abstract

Objective: To determine serial changes in the pattern, distribution, and extent of disease over time, and to determine if any specific findings could be used to predict prognosis in patients with pulmonary sarcoidosis, we reviewed the CT scans of 18 patients with pulmonary sarcoidosis.

Materials and methods: The study included 18 patients with biopsy-proved sarcoidosis and pulmonary abnormalities who had two serial high-resolution CT examinations (1.5-mm collimation, high-spatial-frequency reconstruction algorithm) 4-49 months apart. Initial and follow-up CT scans were evaluated independently and then directly compared with each other by two observers. Scans were assessed for the presence, extent, and severity of ground-glass, nodular, and irregular linear opacities; interlobular septal thickening; cystic air spaces; and architectural distortion. If a finding was predominant, it was noted.

Results: Reversible findings included ground-glass, nodular, and irregular linear opacities and septal thickening. Irreversible findings included cystic air spaces and architectural distortion. Follow-up CT showed overall improvement in 12 of 18 patients, progression in five, and no change in one. A predominant pattern of disease could be determined for each patient. Fourteen patients had predominant nodular opacities; of these, 11 had improved by follow-up. Four had predominant irregular linear opacities; of these, three showed progression of disease on follow-up. The presence of any other specific abnormalities, including ground-glass opacities, was not helpful in predicting improvement or worsening of disease on the follow-up examination.

Conclusion: In pulmonary sarcoidosis, ground-glass, nodular, and irregular linear opacities and interlobular septal thickening represent potentially reversible disease, while cystic air spaces and architectural distortion are irreversible findings. Follow-up CT usually shows improvement in patients with predominant nodular opacities, while disease tends to progress in patients with predominant irregular opacities.