Fibrotic changes in high-resolution computed tomography in patients with sarcoidosis.

The aim of the study is presenting the typical findings of fibrotic changes in high-resolution computed tomography in patients with sarcoidosis. Material comprises a group of 18 patients with sarcoidosis, in whom HRCT examination was performed. The scanning was performed from lung apices to the level of diaphragm, at full inspiration with patients in supine position. The presence and character of HRCT findings were noted and analyzed. Additional expiratory scans were performed to diagnose air-trapping, and in case of subpleural densities in posterior, dependent lung areas additional scans were obtaining in prone patients positions. Fibrotic changes were found in the area of confluent nodular lesions in five patients. In these fibrotic areas the bronchiectasis, as well as parenchymal bands and fibrotic masses were seen. In six patients the reticular pattern was the predominant pathology. Thickened lobular septa did not resolve during the remission of the diseases, suggesting the presence of irreversible, reticular fibrotic changes. Intensive fibrosis led towards destruction of the lung parenchyma, with honeycombing involving large lung areas. In the areas of active disease fibrotic changes with traction bronchiectasis were accompanied by the confluent nodular changes and presence of consolidation. After resolving of active reversible changes the intensive fibrosis with large bronchiectasis forming the honeycombing pattern with reticular changes were seen in five patients. In three cases the most intensive changes both fibrotic and productive (granuloma) changes were localized in the lower lobe, mimicking the idiopathic pulmonary fibrosis. The classical HRCT findings in sarcoidosis are well known. But most of them, nodules, ground glass opacities, peribronchovascular thickening or hilar adenopathy are reversible. The irreversible fibrotic changes develop in about 25% of patients. In the early stage they are subtle and invisible on plain radiographs or even on normal CT sections. So the HRCT is necessary to reveal fibrotic changes in patients with sarcoidosis and to monitor the progression of the diseases. Therefore, the good knowledge of HRCT signs of fibrosis is essential.