Serial high-resolution computed tomography imaging in patients with wegener granulomatosis: differentiation between active inflammatory and chronic fibrotic lesions

Purpose: To evaluate pulmonary pathologies in Wegener granulomatosis with sequential computed tomography (CT) in order to differentiate active inflammatory lesions from chronic fibrotic lesions. Material and Methods: Serial CT findings in 38 patients with Wegener granulomatosis were retrospectively analyzed (mean follow-up period, 21 months). The presence, extension, and distribution of the following findings were evaluated with CT: parenchymal nodules, masses, ground-glass attenuation, airspace consolidation, bronchial wall-thickening, bronchiectasis, linear areas of attenuation, pleural irregularities, pleural effusions, hilar and mediastinal lymphadenopathy. Results: Observed in 92% of patients, nodules were the most common CT pathology. Areas of ground-glass attenuation, consolidation, masses of linear attenuation, and tracheal/bronchial wall-thickening were detected in 24%, 26%, 32%, 39%, and 68% of patients. At follow-up, the clearance of lesions was most consistent for areas of ground-glass attenuation (89%), masses (87%), and cavitated nodules (85%). In the follow-up scan, 58% of all nodules, 47% of pulmonary consolidations, and 66% of bronchial wall-thickening were completely resolved. Areas of bronchiectasis and septal/non-septal lines remained stable in 70% and 71% of patients. Conclusion: The majority of the lesions decreased or resolved completely with or without areas of linear attenuation. Ground-glass attenuation, cavitated nodules and masses appear to represent active inflammatory lesions. In most probability, areas of bronchiectasis and septal/non-septal lines more often represent chronic fibrotic changes rather than active inflammatory changes. In combination with clinical evaluation and bronchoscopy, CT assists in the assessment of disease activity.